Orthopedics

ABSTRACT

Antegrade reamed intramedullary nailing has the advantages of high fracture union and early weight-bearing, making it the gold standard for fixation of diaphyseal femur fractures. However, knowledge of distal femoral anatomy may mitigate the risk of secondary complications.

We present a previously unrecognized complication of antegrade femoral nailing in which a 23-year-old man sustained iatrogenic rupture of the medial patellofemoral ligament (MPFL) caused by the distal interlocking screw of the femoral nail. The patient had a history of antegrade intramedullary nailing that was revised for rotational malalignment, after which he began experiencing recurrent episodes of atraumatic bloody joint effusion and swelling of the right knee with associated patellar instability. Plain radiographs and magnetic resonance imaging revealed a large effusion with a prominent intra-articular distal interlocking screw disrupting the MPFL. The patient underwent a right knee arthroscopic-assisted MPFL reconstruction and removal of the distal interlocking screw. Following surgery, the patient experienced resolution of his effusions, no recurrent patellar instability, and was able to return to his activities.

This case demonstrates that iatrogenic MPFL injury is a potential complication of antegrade femoral nailing and a previously unrecognized cause of patellar instability. Surgeons should be aware of this potential complication and strive to avoid the MPFL origin when placing their distal interlocking screw.

Continue to: Reamed intramedullary nails...

Reamed intramedullary nails are the gold standard for fixation of femoral diaphyseal fractures.¹ Antegrade or retrograde nails are effective options, with the choice of technique based on factors including surgeon preference, patient factors, and concomitant injuries.² Interlocking screws are generally placed to allow control of both rotation and length.¹ Advantages of intramedullary treatment of femoral diaphyseal fractures compared with plate fixation include low rates of infection, lower nonunion rate, and faster patient mobilization and weight-bearing.³

Complications of antegrade intramedullary fixation of femoral shaft fractures include infection, nonunion, malunion, anterior cortical perforation, heterotopic ossification, abductor weakness, and soft tissue irritation from interlocking screws.^2-4 Femoral intramedullary nails are not routinely removed because the hardware is rarely symptomatic and removing the nail involves additional surgical morbidity with the potential for complications.⁵ Interlocking screws are removed in select cases due to soft tissue irritation, generally after fracture union. Although hardware removal may help in select cases, removal of intramedullary nails is associated with low rates of symptom resolution.^6-8

We present a case of iatrogenic medial patellofemoral ligament (MPFL) disruption by the distal interlocking screw leading to patellar instability, a previously unrecognized complication of antegrade femoral nailing for femoral diaphyseal fractures. The patient provided written informed consent for print and electronic publication of this case report.

CASE REPORT

We present a case of a 23-year-old man whose status was 2 years post antegrade reamed femoral intramedullary nailing at an outside institution for a right diaphyseal femur fracture. This issue was revised for external rotational malalignment, and he presented with right anterior knee pain, recurrent patellar subluxation, and recurrent effusions. The extent of external rotational malalignment and subsequent rotational correction were not evident from the available outside institution records. These symptoms began after his femoral nail revision for malalignment, and he had no subsequent trauma. The femoral fracture healed uneventfully. The patient denied any history of knee pain, swelling, or patellar instability before his femoral nail revision for malalignment. These episodes of effusion, instability, and pain occurred several times per year, generally with activities of daily living (ADL). On one occasion, he presented to a local emergency room where knee aspiration revealed no evidence of crystals or infection. The patient was referred to the senior author (Dr. Nho) for consultation.

Physical examination revealed right knee full extension with flexion to 80°. A moderate right knee effusion was present. The patient was tender over the medial femoral epicondyle and the superomedial aspect of the patella without joint line tenderness. Lateral patellar instability was present with 2 quadrants of translation (compared with 1 on the contralateral side) and patellar apprehension. The patient’s knee was ligamentously stable, and meniscal signs were absent. His lower extremity rotational profile was symmetric to the contralateral uninjured side.

Right femur and knee X-rays showed an antegrade intramedullary nail with a well-healed diaphyseal fracture and a single distal interlocking screw oriented from posterolateral to anteromedial (Figures 1A-1G). The screw tip was prominent on sunrise X-ray view anterior to the medial femoral epicondyle (Figure 1C). Magnetic resonance imaging demonstrated a large effusion and lateral patellar subluxation with a prominent intra-articular distal interlocking screw disrupting the MPFL near the femoral attachment (Figure 2). Patellar height, trochlear morphology, and tibial tubercle-trochlear groove distance were assessed and found to be normal.

Continue to: The patient elected...

The patient elected to have a right knee arthroscopic-assisted MPFL reconstruction and removal of the distal interlocking screw. Diagnostic arthroscopy revealed the distal interlocking screw to be intra-articular medially, prominent by 3 mm causing attritional disruption of the mid-substance MPFL (Figure 3A). The patella was noted to be subluxated and tracking laterally (Figure 3B). Both the anterior cruciate ligament and posterior cruciate ligament were intact, and menisci and articular cartilage were normal. The distal interlocking screw was removed under fluoroscopic guidance through a small lateral incision (Figure 3C).

Due to the nature of the longstanding attritional disruption of the MPFL in this case with associated patellar instability over a 2-year period, the decision was made to proceed with formal MPFL reconstruction as opposed to repair. A 2-cm incision was made at the medial aspect of the patella. The proximal half of the patella was decorticated. Guide pins were placed within the proximal half of the patella, ensuring at least a 1-cm bone bridge between them, and two 4.75-mm SwiveLock suture anchors (Arthrex) were inserted. A semitendinosus graft was used for MPFL reconstruction with the 2 ends of the graft secured to 2 suture anchors with a whipstitch. Lateral fluoroscopy was used to identify Schöttle’s point, denoting the femoral origin of the MPFL⁹ (Figure 3D). A 2-cm incision was made at this location. A guide pin was then placed at Schöttle’s point under fluoroscopic guidance, aimed proximally, and the knee was brought through a range of motion (ROM), to verify graft isometry. Once verified, the guide pin was over-reamed to 8 mm. The layer between the retinaculum and the capsule was carefully dissected, and the graft was passed extra-articularly in the plane between the retinaculum and the capsule, out through the medial incision, and docked into the bone tunnel. An 8-mm BioComposite interference screw (Arthrex) was then placed with the knee flexed to 30°. The knee was then passed through a ROM and an arthroscopic evaluation confirmed that the patella was no longer subluxated laterally. There was normal tracking of the patellofemoral joint on arthroscopic evaluation.

Postoperatively, the patient was maintained in a hinged knee brace for 6 weeks. He was weight-bearing as tolerated when locked in full extension beginning immediately postoperatively, and allowed to unlock the brace to start non-weight-bearing active flexion and extension with therapy on postoperative day 1. Radiographs confirmed removal of the distal interlocking screw (Figures 4A, 4B). Following surgery, the patient experienced resolution of his effusions, no recurrent patellar instability at 1-year postoperative, and was able to return to his ADL and recreational sporting activities (Knee Injury and Osteoarthritis Outcome Score [KOOS] ADL, 100; KOOS sporting and recreational activities, 95; quality of life, 100; Marx Activity Rating Scale, 12).

DISCUSSION

The MPFL connects the superomedial edge of the patella to the medial femur and is injured in nearly 100% of patellar dislocations.⁶ The femoral origin lies between the adductor tubercle and the medial epicondyle.⁷ The MPFL prevents lateral subluxation of the patella and acts as the major restraint during the first 20° of knee flexion. Although radiographic parameters for identifying the MPFL femoral origin have been defined by both Schöttle and colleagues⁹ and Stephen and colleagues¹⁰, it is important to check the isometry intraoperatively through a ROM when performing MPFL reconstruction. In this case, the patient’s history and physical examination showed patellar instability, which was determined to be iatrogenically related to the distal interlocking screw rupture of the MPFL. Following screw removal and MPFL reconstruction, the patient had no further symptoms of pain, effusion, or patellar instability and returned to his normal activities.

Femoral malrotation following intramedullary nailing of femoral shaft fractures is a common complication,⁴ with a 22% incidence of malrotation of at least 15° in 1 series from an academic trauma center.¹¹ There are mixed data as to whether malrotation is more common in complex fracture patterns, in cases performed during night hours, and in cases performed by non-trauma fellowship-trained surgeons.^11-13 The natural history of malrotation is not well elucidated, but there is some suggestion that it alters load bearing in the distal joints of the involved leg including the patellofemoral joint. Patients also may not tolerate malrotation due to the abnormal foot progression angle, particularly with malrotation >15°.⁴ In this case, the patient’s initial femoral nail was placed in an externally rotated position, requiring revision. The result of this was an unusual trajectory of the distal interlocking screw from posterolateral to anteromedial. Combined with the prominent screw tip, the trajectory of this distal interlocking screw likely contributed to the injury to the MPFL observed in this case. This trajectory would also pose potential risk to the common peroneal nerve, which is usually situated posterior to the insertion point for distal femoral interlocking screws. The prominent distal interlock screw is a well-recognized problem with femoral intramedullary nails. This issue results from the tapering of the width of the distal femur from being larger posteriorly to being smaller anteriorly. To avoid placement of a prominent distal interlocking screw, surgeons often will obtain an intraoperative anterior-posterior radiograph with the lower extremity in 30° of internal rotation to account for the angle of the medial aspect of the distal femur.

This practice represents, to our knowledge, a previously unreported cause of patellar instability as well as an unreported complication of antegrade femoral intramedullary nailing. Surgeons treating these conditions should consider this potential complication and pursue advanced imaging if patients present with these complaints after femoral intramedullary nail placement. Knowledge of both MPFL origin and insertional anatomy and avoidance of prominent distal interlocking screws in the region of the MPFL, if possible, would likely prevent this complication.

Limitations of this study include the case report design, which makes it impossible to comment on the incidence of this complication or to make comparisons regarding treatment options. There is, of course, the possibility that the patient had a concurrent MPFL injury from the injury in which he sustained the femur fracture. Nevertheless, the clinical history, examination, imaging, and arthroscopic findings all strongly suggest that the prominent distal interlocking screw was the cause of his MPFL injury and patellar instability. Finally, the point widely defined by Schöttle and colleagues¹² was used for MPFL reconstruction in this case based on an intraoperative true lateral radiograph of the distal femur. It should be noted that recent literature has debated the accuracy of this method for determining the femoral origin, the anatomy of the MPFL in relation to the quadriceps, and type of fixation for MPFL reconstruction with some advocating soft tissue only fixation.^14-17 For purposes of this case report, we focused on a different cause of MPFL disruption in this patient and our technique for MPFL reconstruction.

CONCLUSION

This case demonstrates that iatrogenic MPFL injury is a potential complication of antegrade femoral nailing and a previously unrecognized cause of patellar instability. Surgeons should be aware of this potential complication and strive to avoid the MPFL origin when placing their distal interlocking screw.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Antegrade reamed intramedullary nailing has the advantages of high fracture union and early weight-bearing, making it the gold standard for fixation of diaphyseal femur fractures. However, knowledge of distal femoral anatomy may mitigate the risk of secondary complications.

We present a previously unrecognized complication of antegrade femoral nailing in which a 23-year-old man sustained iatrogenic rupture of the medial patellofemoral ligament (MPFL) caused by the distal interlocking screw of the femoral nail. The patient had a history of antegrade intramedullary nailing that was revised for rotational malalignment, after which he began experiencing recurrent episodes of atraumatic bloody joint effusion and swelling of the right knee with associated patellar instability. Plain radiographs and magnetic resonance imaging revealed a large effusion with a prominent intra-articular distal interlocking screw disrupting the MPFL. The patient underwent a right knee arthroscopic-assisted MPFL reconstruction and removal of the distal interlocking screw. Following surgery, the patient experienced resolution of his effusions, no recurrent patellar instability, and was able to return to his activities.

This case demonstrates that iatrogenic MPFL injury is a potential complication of antegrade femoral nailing and a previously unrecognized cause of patellar instability. Surgeons should be aware of this potential complication and strive to avoid the MPFL origin when placing their distal interlocking screw.

Continue to: Reamed intramedullary nails...

Reamed intramedullary nails are the gold standard for fixation of femoral diaphyseal fractures.¹ Antegrade or retrograde nails are effective options, with the choice of technique based on factors including surgeon preference, patient factors, and concomitant injuries.² Interlocking screws are generally placed to allow control of both rotation and length.¹ Advantages of intramedullary treatment of femoral diaphyseal fractures compared with plate fixation include low rates of infection, lower nonunion rate, and faster patient mobilization and weight-bearing.³

Complications of antegrade intramedullary fixation of femoral shaft fractures include infection, nonunion, malunion, anterior cortical perforation, heterotopic ossification, abductor weakness, and soft tissue irritation from interlocking screws.^2-4 Femoral intramedullary nails are not routinely removed because the hardware is rarely symptomatic and removing the nail involves additional surgical morbidity with the potential for complications.⁵ Interlocking screws are removed in select cases due to soft tissue irritation, generally after fracture union. Although hardware removal may help in select cases, removal of intramedullary nails is associated with low rates of symptom resolution.^6-8

We present a case of iatrogenic medial patellofemoral ligament (MPFL) disruption by the distal interlocking screw leading to patellar instability, a previously unrecognized complication of antegrade femoral nailing for femoral diaphyseal fractures. The patient provided written informed consent for print and electronic publication of this case report.

CASE REPORT

We present a case of a 23-year-old man whose status was 2 years post antegrade reamed femoral intramedullary nailing at an outside institution for a right diaphyseal femur fracture. This issue was revised for external rotational malalignment, and he presented with right anterior knee pain, recurrent patellar subluxation, and recurrent effusions. The extent of external rotational malalignment and subsequent rotational correction were not evident from the available outside institution records. These symptoms began after his femoral nail revision for malalignment, and he had no subsequent trauma. The femoral fracture healed uneventfully. The patient denied any history of knee pain, swelling, or patellar instability before his femoral nail revision for malalignment. These episodes of effusion, instability, and pain occurred several times per year, generally with activities of daily living (ADL). On one occasion, he presented to a local emergency room where knee aspiration revealed no evidence of crystals or infection. The patient was referred to the senior author (Dr. Nho) for consultation.

Physical examination revealed right knee full extension with flexion to 80°. A moderate right knee effusion was present. The patient was tender over the medial femoral epicondyle and the superomedial aspect of the patella without joint line tenderness. Lateral patellar instability was present with 2 quadrants of translation (compared with 1 on the contralateral side) and patellar apprehension. The patient’s knee was ligamentously stable, and meniscal signs were absent. His lower extremity rotational profile was symmetric to the contralateral uninjured side.

Right femur and knee X-rays showed an antegrade intramedullary nail with a well-healed diaphyseal fracture and a single distal interlocking screw oriented from posterolateral to anteromedial (Figures 1A-1G). The screw tip was prominent on sunrise X-ray view anterior to the medial femoral epicondyle (Figure 1C). Magnetic resonance imaging demonstrated a large effusion and lateral patellar subluxation with a prominent intra-articular distal interlocking screw disrupting the MPFL near the femoral attachment (Figure 2). Patellar height, trochlear morphology, and tibial tubercle-trochlear groove distance were assessed and found to be normal.

Continue to: The patient elected...

The patient elected to have a right knee arthroscopic-assisted MPFL reconstruction and removal of the distal interlocking screw. Diagnostic arthroscopy revealed the distal interlocking screw to be intra-articular medially, prominent by 3 mm causing attritional disruption of the mid-substance MPFL (Figure 3A). The patella was noted to be subluxated and tracking laterally (Figure 3B). Both the anterior cruciate ligament and posterior cruciate ligament were intact, and menisci and articular cartilage were normal. The distal interlocking screw was removed under fluoroscopic guidance through a small lateral incision (Figure 3C).

Due to the nature of the longstanding attritional disruption of the MPFL in this case with associated patellar instability over a 2-year period, the decision was made to proceed with formal MPFL reconstruction as opposed to repair. A 2-cm incision was made at the medial aspect of the patella. The proximal half of the patella was decorticated. Guide pins were placed within the proximal half of the patella, ensuring at least a 1-cm bone bridge between them, and two 4.75-mm SwiveLock suture anchors (Arthrex) were inserted. A semitendinosus graft was used for MPFL reconstruction with the 2 ends of the graft secured to 2 suture anchors with a whipstitch. Lateral fluoroscopy was used to identify Schöttle’s point, denoting the femoral origin of the MPFL⁹ (Figure 3D). A 2-cm incision was made at this location. A guide pin was then placed at Schöttle’s point under fluoroscopic guidance, aimed proximally, and the knee was brought through a range of motion (ROM), to verify graft isometry. Once verified, the guide pin was over-reamed to 8 mm. The layer between the retinaculum and the capsule was carefully dissected, and the graft was passed extra-articularly in the plane between the retinaculum and the capsule, out through the medial incision, and docked into the bone tunnel. An 8-mm BioComposite interference screw (Arthrex) was then placed with the knee flexed to 30°. The knee was then passed through a ROM and an arthroscopic evaluation confirmed that the patella was no longer subluxated laterally. There was normal tracking of the patellofemoral joint on arthroscopic evaluation.

Postoperatively, the patient was maintained in a hinged knee brace for 6 weeks. He was weight-bearing as tolerated when locked in full extension beginning immediately postoperatively, and allowed to unlock the brace to start non-weight-bearing active flexion and extension with therapy on postoperative day 1. Radiographs confirmed removal of the distal interlocking screw (Figures 4A, 4B). Following surgery, the patient experienced resolution of his effusions, no recurrent patellar instability at 1-year postoperative, and was able to return to his ADL and recreational sporting activities (Knee Injury and Osteoarthritis Outcome Score [KOOS] ADL, 100; KOOS sporting and recreational activities, 95; quality of life, 100; Marx Activity Rating Scale, 12).

DISCUSSION

The MPFL connects the superomedial edge of the patella to the medial femur and is injured in nearly 100% of patellar dislocations.⁶ The femoral origin lies between the adductor tubercle and the medial epicondyle.⁷ The MPFL prevents lateral subluxation of the patella and acts as the major restraint during the first 20° of knee flexion. Although radiographic parameters for identifying the MPFL femoral origin have been defined by both Schöttle and colleagues⁹ and Stephen and colleagues¹⁰, it is important to check the isometry intraoperatively through a ROM when performing MPFL reconstruction. In this case, the patient’s history and physical examination showed patellar instability, which was determined to be iatrogenically related to the distal interlocking screw rupture of the MPFL. Following screw removal and MPFL reconstruction, the patient had no further symptoms of pain, effusion, or patellar instability and returned to his normal activities.

Femoral malrotation following intramedullary nailing of femoral shaft fractures is a common complication,⁴ with a 22% incidence of malrotation of at least 15° in 1 series from an academic trauma center.¹¹ There are mixed data as to whether malrotation is more common in complex fracture patterns, in cases performed during night hours, and in cases performed by non-trauma fellowship-trained surgeons.^11-13 The natural history of malrotation is not well elucidated, but there is some suggestion that it alters load bearing in the distal joints of the involved leg including the patellofemoral joint. Patients also may not tolerate malrotation due to the abnormal foot progression angle, particularly with malrotation >15°.⁴ In this case, the patient’s initial femoral nail was placed in an externally rotated position, requiring revision. The result of this was an unusual trajectory of the distal interlocking screw from posterolateral to anteromedial. Combined with the prominent screw tip, the trajectory of this distal interlocking screw likely contributed to the injury to the MPFL observed in this case. This trajectory would also pose potential risk to the common peroneal nerve, which is usually situated posterior to the insertion point for distal femoral interlocking screws. The prominent distal interlock screw is a well-recognized problem with femoral intramedullary nails. This issue results from the tapering of the width of the distal femur from being larger posteriorly to being smaller anteriorly. To avoid placement of a prominent distal interlocking screw, surgeons often will obtain an intraoperative anterior-posterior radiograph with the lower extremity in 30° of internal rotation to account for the angle of the medial aspect of the distal femur.

This practice represents, to our knowledge, a previously unreported cause of patellar instability as well as an unreported complication of antegrade femoral intramedullary nailing. Surgeons treating these conditions should consider this potential complication and pursue advanced imaging if patients present with these complaints after femoral intramedullary nail placement. Knowledge of both MPFL origin and insertional anatomy and avoidance of prominent distal interlocking screws in the region of the MPFL, if possible, would likely prevent this complication.

Limitations of this study include the case report design, which makes it impossible to comment on the incidence of this complication or to make comparisons regarding treatment options. There is, of course, the possibility that the patient had a concurrent MPFL injury from the injury in which he sustained the femur fracture. Nevertheless, the clinical history, examination, imaging, and arthroscopic findings all strongly suggest that the prominent distal interlocking screw was the cause of his MPFL injury and patellar instability. Finally, the point widely defined by Schöttle and colleagues¹² was used for MPFL reconstruction in this case based on an intraoperative true lateral radiograph of the distal femur. It should be noted that recent literature has debated the accuracy of this method for determining the femoral origin, the anatomy of the MPFL in relation to the quadriceps, and type of fixation for MPFL reconstruction with some advocating soft tissue only fixation.^14-17 For purposes of this case report, we focused on a different cause of MPFL disruption in this patient and our technique for MPFL reconstruction.

CONCLUSION

This case demonstrates that iatrogenic MPFL injury is a potential complication of antegrade femoral nailing and a previously unrecognized cause of patellar instability. Surgeons should be aware of this potential complication and strive to avoid the MPFL origin when placing their distal interlocking screw.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Antegrade reamed intramedullary nailing has the advantages of high fracture union and early weight-bearing, making it the gold standard for fixation of diaphyseal femur fractures. However, knowledge of distal femoral anatomy may mitigate the risk of secondary complications.

We present a previously unrecognized complication of antegrade femoral nailing in which a 23-year-old man sustained iatrogenic rupture of the medial patellofemoral ligament (MPFL) caused by the distal interlocking screw of the femoral nail. The patient had a history of antegrade intramedullary nailing that was revised for rotational malalignment, after which he began experiencing recurrent episodes of atraumatic bloody joint effusion and swelling of the right knee with associated patellar instability. Plain radiographs and magnetic resonance imaging revealed a large effusion with a prominent intra-articular distal interlocking screw disrupting the MPFL. The patient underwent a right knee arthroscopic-assisted MPFL reconstruction and removal of the distal interlocking screw. Following surgery, the patient experienced resolution of his effusions, no recurrent patellar instability, and was able to return to his activities.

This case demonstrates that iatrogenic MPFL injury is a potential complication of antegrade femoral nailing and a previously unrecognized cause of patellar instability. Surgeons should be aware of this potential complication and strive to avoid the MPFL origin when placing their distal interlocking screw.

Continue to: Reamed intramedullary nails...

Reamed intramedullary nails are the gold standard for fixation of femoral diaphyseal fractures.¹ Antegrade or retrograde nails are effective options, with the choice of technique based on factors including surgeon preference, patient factors, and concomitant injuries.² Interlocking screws are generally placed to allow control of both rotation and length.¹ Advantages of intramedullary treatment of femoral diaphyseal fractures compared with plate fixation include low rates of infection, lower nonunion rate, and faster patient mobilization and weight-bearing.³

Complications of antegrade intramedullary fixation of femoral shaft fractures include infection, nonunion, malunion, anterior cortical perforation, heterotopic ossification, abductor weakness, and soft tissue irritation from interlocking screws.^2-4 Femoral intramedullary nails are not routinely removed because the hardware is rarely symptomatic and removing the nail involves additional surgical morbidity with the potential for complications.⁵ Interlocking screws are removed in select cases due to soft tissue irritation, generally after fracture union. Although hardware removal may help in select cases, removal of intramedullary nails is associated with low rates of symptom resolution.^6-8

We present a case of iatrogenic medial patellofemoral ligament (MPFL) disruption by the distal interlocking screw leading to patellar instability, a previously unrecognized complication of antegrade femoral nailing for femoral diaphyseal fractures. The patient provided written informed consent for print and electronic publication of this case report.

CASE REPORT

We present a case of a 23-year-old man whose status was 2 years post antegrade reamed femoral intramedullary nailing at an outside institution for a right diaphyseal femur fracture. This issue was revised for external rotational malalignment, and he presented with right anterior knee pain, recurrent patellar subluxation, and recurrent effusions. The extent of external rotational malalignment and subsequent rotational correction were not evident from the available outside institution records. These symptoms began after his femoral nail revision for malalignment, and he had no subsequent trauma. The femoral fracture healed uneventfully. The patient denied any history of knee pain, swelling, or patellar instability before his femoral nail revision for malalignment. These episodes of effusion, instability, and pain occurred several times per year, generally with activities of daily living (ADL). On one occasion, he presented to a local emergency room where knee aspiration revealed no evidence of crystals or infection. The patient was referred to the senior author (Dr. Nho) for consultation.

Physical examination revealed right knee full extension with flexion to 80°. A moderate right knee effusion was present. The patient was tender over the medial femoral epicondyle and the superomedial aspect of the patella without joint line tenderness. Lateral patellar instability was present with 2 quadrants of translation (compared with 1 on the contralateral side) and patellar apprehension. The patient’s knee was ligamentously stable, and meniscal signs were absent. His lower extremity rotational profile was symmetric to the contralateral uninjured side.

Right femur and knee X-rays showed an antegrade intramedullary nail with a well-healed diaphyseal fracture and a single distal interlocking screw oriented from posterolateral to anteromedial (Figures 1A-1G). The screw tip was prominent on sunrise X-ray view anterior to the medial femoral epicondyle (Figure 1C). Magnetic resonance imaging demonstrated a large effusion and lateral patellar subluxation with a prominent intra-articular distal interlocking screw disrupting the MPFL near the femoral attachment (Figure 2). Patellar height, trochlear morphology, and tibial tubercle-trochlear groove distance were assessed and found to be normal.

Continue to: The patient elected...

The patient elected to have a right knee arthroscopic-assisted MPFL reconstruction and removal of the distal interlocking screw. Diagnostic arthroscopy revealed the distal interlocking screw to be intra-articular medially, prominent by 3 mm causing attritional disruption of the mid-substance MPFL (Figure 3A). The patella was noted to be subluxated and tracking laterally (Figure 3B). Both the anterior cruciate ligament and posterior cruciate ligament were intact, and menisci and articular cartilage were normal. The distal interlocking screw was removed under fluoroscopic guidance through a small lateral incision (Figure 3C).

Due to the nature of the longstanding attritional disruption of the MPFL in this case with associated patellar instability over a 2-year period, the decision was made to proceed with formal MPFL reconstruction as opposed to repair. A 2-cm incision was made at the medial aspect of the patella. The proximal half of the patella was decorticated. Guide pins were placed within the proximal half of the patella, ensuring at least a 1-cm bone bridge between them, and two 4.75-mm SwiveLock suture anchors (Arthrex) were inserted. A semitendinosus graft was used for MPFL reconstruction with the 2 ends of the graft secured to 2 suture anchors with a whipstitch. Lateral fluoroscopy was used to identify Schöttle’s point, denoting the femoral origin of the MPFL⁹ (Figure 3D). A 2-cm incision was made at this location. A guide pin was then placed at Schöttle’s point under fluoroscopic guidance, aimed proximally, and the knee was brought through a range of motion (ROM), to verify graft isometry. Once verified, the guide pin was over-reamed to 8 mm. The layer between the retinaculum and the capsule was carefully dissected, and the graft was passed extra-articularly in the plane between the retinaculum and the capsule, out through the medial incision, and docked into the bone tunnel. An 8-mm BioComposite interference screw (Arthrex) was then placed with the knee flexed to 30°. The knee was then passed through a ROM and an arthroscopic evaluation confirmed that the patella was no longer subluxated laterally. There was normal tracking of the patellofemoral joint on arthroscopic evaluation.

Postoperatively, the patient was maintained in a hinged knee brace for 6 weeks. He was weight-bearing as tolerated when locked in full extension beginning immediately postoperatively, and allowed to unlock the brace to start non-weight-bearing active flexion and extension with therapy on postoperative day 1. Radiographs confirmed removal of the distal interlocking screw (Figures 4A, 4B). Following surgery, the patient experienced resolution of his effusions, no recurrent patellar instability at 1-year postoperative, and was able to return to his ADL and recreational sporting activities (Knee Injury and Osteoarthritis Outcome Score [KOOS] ADL, 100; KOOS sporting and recreational activities, 95; quality of life, 100; Marx Activity Rating Scale, 12).

DISCUSSION

The MPFL connects the superomedial edge of the patella to the medial femur and is injured in nearly 100% of patellar dislocations.⁶ The femoral origin lies between the adductor tubercle and the medial epicondyle.⁷ The MPFL prevents lateral subluxation of the patella and acts as the major restraint during the first 20° of knee flexion. Although radiographic parameters for identifying the MPFL femoral origin have been defined by both Schöttle and colleagues⁹ and Stephen and colleagues¹⁰, it is important to check the isometry intraoperatively through a ROM when performing MPFL reconstruction. In this case, the patient’s history and physical examination showed patellar instability, which was determined to be iatrogenically related to the distal interlocking screw rupture of the MPFL. Following screw removal and MPFL reconstruction, the patient had no further symptoms of pain, effusion, or patellar instability and returned to his normal activities.

Femoral malrotation following intramedullary nailing of femoral shaft fractures is a common complication,⁴ with a 22% incidence of malrotation of at least 15° in 1 series from an academic trauma center.¹¹ There are mixed data as to whether malrotation is more common in complex fracture patterns, in cases performed during night hours, and in cases performed by non-trauma fellowship-trained surgeons.^11-13 The natural history of malrotation is not well elucidated, but there is some suggestion that it alters load bearing in the distal joints of the involved leg including the patellofemoral joint. Patients also may not tolerate malrotation due to the abnormal foot progression angle, particularly with malrotation >15°.⁴ In this case, the patient’s initial femoral nail was placed in an externally rotated position, requiring revision. The result of this was an unusual trajectory of the distal interlocking screw from posterolateral to anteromedial. Combined with the prominent screw tip, the trajectory of this distal interlocking screw likely contributed to the injury to the MPFL observed in this case. This trajectory would also pose potential risk to the common peroneal nerve, which is usually situated posterior to the insertion point for distal femoral interlocking screws. The prominent distal interlock screw is a well-recognized problem with femoral intramedullary nails. This issue results from the tapering of the width of the distal femur from being larger posteriorly to being smaller anteriorly. To avoid placement of a prominent distal interlocking screw, surgeons often will obtain an intraoperative anterior-posterior radiograph with the lower extremity in 30° of internal rotation to account for the angle of the medial aspect of the distal femur.

This practice represents, to our knowledge, a previously unreported cause of patellar instability as well as an unreported complication of antegrade femoral intramedullary nailing. Surgeons treating these conditions should consider this potential complication and pursue advanced imaging if patients present with these complaints after femoral intramedullary nail placement. Knowledge of both MPFL origin and insertional anatomy and avoidance of prominent distal interlocking screws in the region of the MPFL, if possible, would likely prevent this complication.

Limitations of this study include the case report design, which makes it impossible to comment on the incidence of this complication or to make comparisons regarding treatment options. There is, of course, the possibility that the patient had a concurrent MPFL injury from the injury in which he sustained the femur fracture. Nevertheless, the clinical history, examination, imaging, and arthroscopic findings all strongly suggest that the prominent distal interlocking screw was the cause of his MPFL injury and patellar instability. Finally, the point widely defined by Schöttle and colleagues¹² was used for MPFL reconstruction in this case based on an intraoperative true lateral radiograph of the distal femur. It should be noted that recent literature has debated the accuracy of this method for determining the femoral origin, the anatomy of the MPFL in relation to the quadriceps, and type of fixation for MPFL reconstruction with some advocating soft tissue only fixation.^14-17 For purposes of this case report, we focused on a different cause of MPFL disruption in this patient and our technique for MPFL reconstruction.

CONCLUSION

This case demonstrates that iatrogenic MPFL injury is a potential complication of antegrade femoral nailing and a previously unrecognized cause of patellar instability. Surgeons should be aware of this potential complication and strive to avoid the MPFL origin when placing their distal interlocking screw.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Despite advancements in surgical technique and understanding of throwing mechanics, controversy persists regarding the treatment of grade III acromioclavicular (AC) joint separations, particularly in throwing athletes. Twenty-eight major league baseball (MLB) orthopedic team physicians were surveyed to determine their definitive management of a grade III AC separation in the dominant arm of a professional baseball pitcher and their experience treating AC joint separations in starting pitchers and position players. Return-to-play outcomes were also evaluated. Twenty (71.4%) team physicians recommended nonoperative intervention compared to 8 (28.6%) who would have operated acutely. Eighteen (64.3%) team physicians had treated at least 1 professional pitcher with a grade III AC separation; 51 (77.3%) pitchers had been treated nonoperatively compared to 15 (22.7%) operatively. No difference was observed in the proportion of pitchers who returned to the same level of play (P = .54), had full, unrestricted range of motion (P = .23), or had full pain relief (P = .19) between the operatively and nonoperatively treated MLB pitchers. The majority (53.6%) of physicians would not include an injection if the injury was treated nonoperatively. Open coracoclavicular reconstruction (65.2%) was preferred for operative cases; 66.7% of surgeons would also include distal clavicle excision as an adjunct procedure. About 90% of physicians would return pitchers to throwing >12 weeks after surgery compared to after 4 to 6 weeks in nonoperatively treated cases. In conclusion, MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in professional pitchers. If operative intervention is required, ligament reconstruction with adjunct distal clavicle excision were the most commonly performed procedures.

Continue to: Despite advancements in surgucal technique...

Despite advancements in surgical technique and improved understanding of the physiology of throwing mechanics, controversy persists regarding the preferred treatment for grade III acromioclavicular (AC) joint separations.^1-6 Nonsurgical management has demonstrated return to prior function with fewer complications.⁷ However, there is a growing body of evidence demonstrating that surgical intervention is associated with more favorable outcomes⁸ and should be considered in patients who place high functional demands on their shoulders.⁹

The reported results on professional athletes in the literature remain ambivalent. Multiple small case reports/series have reported successful nonoperative treatment of elite athletes.^10-12 Not surprisingly, McFarland and colleagues¹³ reported in 1997 that 69% of major league baseball (MLB) team physicians preferred nonoperative treatment for a theoretical starting pitcher sustaining a grade III AC separation 1 week prior to the start of the season. In contrast, reports of an inability to throw at a pre-injury level are equally commonplace.^14,15 Nevertheless, all of these studies were limited to small cohorts, as the incidence of grade III AC separations in elite throwing athletes is relatively uncommon.^13,16

In this study, we re-evaluated the study performed by McFarland and colleagues¹³ in 1997 by surveying all active MLB team orthopedic surgeons. We asked them how they would treat a grade III AC separation in a starting professional baseball pitcher. The physicians were also asked about their personal experience evaluating outcomes in these elite athletes. Given our improved understanding of the anatomy, pathophysiology, and surgical techniques for treating grade III AC separations, we hypothesize that more MLB team physicians would favor operative intervention treatment in professional baseball pitchers, as their vocation places higher demands on their shoulders.

MATERIALS AND METHODS

A questionnaire (Appendix A) was distributed to the team physicians of all 30 MLB teams. In addition to surgeon demographics, including age, years in practice, and years of taking care of an MLB team, the initial section of the questionnaire asked orthopedic surgeons how they would treat a theoretical starting pitcher who sustained a grade III AC joint separation of the dominant throwing arm 1 week prior to the start of the season. Physicians who preferred nonoperative treatment were asked whether they would use an injection (and what type), as well as when they would allow the pitcher to start a progressive interval throwing program. Physicians who preferred operative treatment were asked to rank their indications for operating, what procedure they would use (eg, open vs arthroscopic or coracoclavicular ligament repair vs reconstruction), and whether the surgical intervention would include distal clavicle excision. Both groups of physicians were also asked if their preferred treatment would change if the injury were to occur at the end of the season.

The second portion of the questionnaire asked surgeons about their experience treating AC joint separations in both starting pitchers and position players, as well as to describe the long-term outcomes of their preferred treatment, including time to return to full clearance for pitching, whether their patients returned to their prior level of play, and whether these patients had full pain relief. Finally, physicians were asked if any of the nonoperatively treated players ultimately crossed over and required operative intervention.

Continue to: Statistics...

STATISTICS

Descriptive statistics were used for continuous variables, and frequencies were used for categorical variables. Linear regression was performed to determine the correlation between the physician’s training or experience in treating AC joint separations and their recommended treatment. Fischer’s exact test/chi-square analysis was used to compare categorical variables. All tests were conducted using 2-sided hypothesis testing with statistical significance set at P < .05. All statistical analyses were conducted with SPSS 21.0 software (IBM Corporation).

RESULTS

A total of 28 MLB team physicians completed the questionnaires from 18 of the 30 MLB teams. The average age of the responders was 50.5 years (range, 34-60 years), with an average of 18.2 years in practice (range, 2-30 years) and 10.8 years (range, 1-24 years) taking care of their current professional baseball team. About 82% of the team physicians completed a sports medicine fellowship. On average, physicians saw 16.6 (range, 5-50) grade III or higher AC joint separations per year, and operated on 4.6 (range, 0-10) per year.

Nonoperative treatment was the preferred treatment for a grade III AC joint separation in a starting professional baseball pitcher for the majority of team physicians (20/28). No correlation was observed between the physician’s age (P = .881), years in practice (P = .915), years taking care of their professional team (P = .989), percentage of practice focused on shoulders (P = .986), number of AC joint injuries seen (P = .325), or number of surgeries performed per year (P = .807) with the team physician’s preferred treatment. Compared to the proportion reported originally by McFarland and colleagues¹³ in 1997 (69%), there was no difference in the proportion of team physicians that recommended nonoperative treatment (P = 1).

If treating this injury nonoperatively, 46.4% of physicians would also use an injection, with orthobiologics (eg, platelet-rich plasma) as the most popular choice (Table 1). No consensus was provided on the timeframe to return pitchers back to a progressive interval throwing program; however, 46.67% of physicians would return pitchers 4 to 6 weeks after a nonoperatively treated injury, while 35.7% would return pitchers 7 to 12 weeks after the initial injury.

Table 1. Treatment Preferences of Grade III AC Separation by MLB Team Physicians

^aRespondents were allowed to choose more than 1 treatment in each category. ^bChosen as an adjunct treatment.

Abbreviations: AC, acromioclavicular; MLB, major league baseball.

Most physicians (64.3%) cited functional limitations as the most important reason for indicating operative treatment, followed by pain (21.4%), and a deformity (14.3%). About 65% preferred open coracoclavicular ligament reconstruction. No physician recommended the Weaver-Dunn procedure or use of hardware (eg, hook plate). Of those who preferred an operative intervention, 66.7% would also include a distal clavicle excision, which is significantly higher than the proportion reported by McFarland and colleagues¹³ (23%, P = .0170). About 90% of physicians would return pitchers to play >12 weeks after operative treatment.

Continue to: If the injury occurred at the end ...

If the injury occurred at the end of the season, 7 of the 20 orthopedists (35%) who recommended nonoperative treatment said they would change to an operative intervention. Eighteen of 28 responders would have the same algorithm for MLB position players. Team physicians were less likely to recommend operative intervention in position players due to less demand on the arm and increased ability to accommodate the injury by altering their throwing mechanics.

Eighteen (64%) of the team physicians had treated at least 1 professional pitcher with a grade III AC separation in his dominant arm, and 11 (39.3%) had treated >1. Collectively, team physicians had treated 15 professional pitchers operatively, and 51 nonoperatively; only 3 patients converted to operative intervention after a failed nonoperative treatment.

Of the pitchers treated operatively, 93.3% (14) of pitchers returned to their prior level of pitching. The 1 patient who failed to return to the same level of pitching retired instead of returning to play. About 80% (12) of the pitchers had full pain relief, and 93.3% (14) had full range of motion (ROM). The pitcher who failed to regain full ROM also had a concomitant rotator cuff repair. The only complication reported from an operative intervention was a pitcher who sustained a coracoid fracture 10 months postoperatively while throwing 100 mph. Of the pitchers treated nonoperatively, 96% returned to their prior level of pitching, 92.2% (47) had full complete pain relief when throwing, and 100% had full ROM. No differences were observed between the proportion of pitchers who returned to their prior level of pitching, regained full ROM, or had full pain relief in the operative and nonoperative groups (Table 2).

Table 2. Outcomes of Treatment of Grade III AC Separation in 58 Professional Baseball Players

Abbreviations: AC, acromioclavicular; ROM, range of motion.

DISCUSSION 

Controversy persists regarding the optimal management of acute grade III AC separations, with the current available evidence potentially suggesting better cosmetic and radiological results but no definite differences in clinical results.^1-6,17,18 In the absence of formal clinical practice guidelines, surgeons rely on their own experience or defer to the anecdotal experience of experts in the field. Our initial hypothesis was false in this survey of MLB team physicians taking care of overhead throwing athletes at the highest level. Our results demonstrate that despite improved techniques and an increased understanding of the pathophysiology of AC joint separations, conservative management is still the preferred treatment for acute grade III AC joint separations in professional baseball pitchers. The proportion of team physicians recommending nonoperative treatment in our series was essentially equivalent to the results reported by McFarland and colleagues¹³ in 1997, suggesting that the pendulum continues to favor conservative management initially. This status quo likely reflects both the dearth of literature suggesting a substantial benefit of acute operative repair, as well as the ability to accommodate with conservative measures after most grade III AC injuries, even at the highest level of athletic competition.

These results are also consistent with trends from the last few decades. In the 1970s, the overwhelming preference for treating an acute complete AC joint separation was surgical repair, with Powers and Bach¹⁰ reporting in a 1974 survey of 163 chairmen of orthopedic programs around the country that 91.5% advocated surgical treatment. However, surgical preference had reversed by the 1990s. Of the 187 chairmen and 59 team physicians surveyed by Cox¹⁹ in 1992, 72% and 86% respectively preferred nonoperative treatment in a theoretical 21-year-old athlete with a grade III AC separation. Nissen and Chatterjee²⁰ reported in 2007 on a survey of all American Orthopaedic Society for Sports Medicine surgeons (N = 577) and Accreditation Council for Graduate Medical Education orthopedic program residency directors (N = 87) that >80% of responders preferred conservative measures for this acute injury. The reversal of trends has also been corroborated by recent multicenter trials demonstrating no difference in clinical outcomes between operative and nonoperative treatment of high grade AC joint dislocations, albeit these patients were not all high level overhead throwing athletes.^17,18

Continue to: The trends in surgical interventions are notable...

The trends in surgical interventions are notable within the smaller subset of patients who are indicated for operative repair. Use of hardware and primary ligament repair, while popular in the surveys conducted in the 1970s¹⁰ and 1990s¹³ and even present in Nissen and Chatterjee’s²⁰ 2007 survey, were noticeably absent from our survey results, with the majority of respondents preferring open coracoclavicular ligament reconstruction. The role of distal clavicle excision has also expanded, from 23% of team physicians recommending it in 1997¹³ to 57% to 59% in Nissen and Chatterjee’s²⁰ 2007 survey, to 66.7% in our series. This trend is not surprising as several recent cadaveric biomechanical studies have demonstrated that not only do peak graft forces not increase significantly,²¹ the anterior-posterior and superior-inferior motion at the AC joint following ligament reconstruction is maintained despite resection of the lateral clavicle.²² Additionally, primary distal clavicle excision may prevent the development of post-traumatic arthritis at the AC joint and osteolysis of the distal clavicle as a possible pain generator in the future.²³ However, some respondents cautioned against performing a concomitant distal clavicle excision, as some biomechanical data demonstrate that resecting the distal clavicle may lead to increased horizontal translation at the AC joint despite intact superior and posterior AC capsules.²⁴ Professional baseball pitchers may also be more lax and thus prone to more instability. Primary repair or reconstruction may not always lead to complete pre-injury stability in these individuals. This subtle unrecognized instability is hard to diagnosis and may be a persistent source of pain; thus, adding a distal clavicle excision may actually exacerbate the instability.

The nuanced indications for operative intervention, such as the presence of associated lesions were not captured by our survey.²⁵ While most team physicians cited functional limitations as their most common reason for offering surgery, several MLB orthopedic surgeons also commented on evaluating the stability of the AC joint after a grade III injury, akin to the consensus statement from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee²⁶ in 2014 that diversified the Rockwood Grade III AC joint separation into its IIIA and IIIB classifications. The ISAKOS recommendations include initial conservative management and a second evaluation (both clinical and radiographic) for grade III lesions 3 to 6 weeks after the injury. However, as professional baseball is an incredibly profitable sport with an annual revenue approaching $9.5 billion²⁷ and pitching salaries up to $32.5 million in 2015, serious financial considerations must be given to players who wish to avoid undergoing delayed surgery.

This study has shortcomings typical of expert opinion papers. The retrospective nature of this study places the data at risk of recall bias. Objective data (eg, terminal ROM, pain relief, and return to play) were obtained from a retrospective chart review; however, no standard documentation or collection method was used given the number of surgeons involved and, thus, conclusions based on treatment outcomes are imperfect. Another major weakness of this survey is the relatively small number of patients and respondents. An a priori power analysis was not available, as this was a retrospective review. A comparative trial will be necessary to definitively support one treatment over another. Assuming a 95% return to play in the nonoperatively treated group, approximately 300 patients would be needed in a prospective 2-armed study with 80% power to detect a 10% reduction in the incidence of return to play using an alpha level of 0.05 and assuming no loss to follow-up. This sample size would be difficult to achieve in this patient population.

However, compared to past series,¹³ the number of professional baseball players treated by the collective experience of these MLB team physicians is the largest reported to date. As suggested above, the rarity of this condition in elite athletes precludes the ability to have matched controls to definitively determine the optimal treatment, which may explain the lack of difference in the return to play, ROM, and pain relief outcomes. Instead, we can only extrapolate based on the collective anecdotal experience of the MLB team physicians.

CONCLUSION

Despite advances in surgical technique and understanding of throwing mechanics, the majority of MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in a professional baseball pitcher. Open coracoclavicular ligament reconstruction was preferred for those who preferred operative intervention. An increasing number of orthopedic surgeons now consider a distal clavicle excision as an adjunct procedure.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Despite advancements in surgical technique and understanding of throwing mechanics, controversy persists regarding the treatment of grade III acromioclavicular (AC) joint separations, particularly in throwing athletes. Twenty-eight major league baseball (MLB) orthopedic team physicians were surveyed to determine their definitive management of a grade III AC separation in the dominant arm of a professional baseball pitcher and their experience treating AC joint separations in starting pitchers and position players. Return-to-play outcomes were also evaluated. Twenty (71.4%) team physicians recommended nonoperative intervention compared to 8 (28.6%) who would have operated acutely. Eighteen (64.3%) team physicians had treated at least 1 professional pitcher with a grade III AC separation; 51 (77.3%) pitchers had been treated nonoperatively compared to 15 (22.7%) operatively. No difference was observed in the proportion of pitchers who returned to the same level of play (P = .54), had full, unrestricted range of motion (P = .23), or had full pain relief (P = .19) between the operatively and nonoperatively treated MLB pitchers. The majority (53.6%) of physicians would not include an injection if the injury was treated nonoperatively. Open coracoclavicular reconstruction (65.2%) was preferred for operative cases; 66.7% of surgeons would also include distal clavicle excision as an adjunct procedure. About 90% of physicians would return pitchers to throwing >12 weeks after surgery compared to after 4 to 6 weeks in nonoperatively treated cases. In conclusion, MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in professional pitchers. If operative intervention is required, ligament reconstruction with adjunct distal clavicle excision were the most commonly performed procedures.

Continue to: Despite advancements in surgucal technique...

Despite advancements in surgical technique and improved understanding of the physiology of throwing mechanics, controversy persists regarding the preferred treatment for grade III acromioclavicular (AC) joint separations.^1-6 Nonsurgical management has demonstrated return to prior function with fewer complications.⁷ However, there is a growing body of evidence demonstrating that surgical intervention is associated with more favorable outcomes⁸ and should be considered in patients who place high functional demands on their shoulders.⁹

The reported results on professional athletes in the literature remain ambivalent. Multiple small case reports/series have reported successful nonoperative treatment of elite athletes.^10-12 Not surprisingly, McFarland and colleagues¹³ reported in 1997 that 69% of major league baseball (MLB) team physicians preferred nonoperative treatment for a theoretical starting pitcher sustaining a grade III AC separation 1 week prior to the start of the season. In contrast, reports of an inability to throw at a pre-injury level are equally commonplace.^14,15 Nevertheless, all of these studies were limited to small cohorts, as the incidence of grade III AC separations in elite throwing athletes is relatively uncommon.^13,16

In this study, we re-evaluated the study performed by McFarland and colleagues¹³ in 1997 by surveying all active MLB team orthopedic surgeons. We asked them how they would treat a grade III AC separation in a starting professional baseball pitcher. The physicians were also asked about their personal experience evaluating outcomes in these elite athletes. Given our improved understanding of the anatomy, pathophysiology, and surgical techniques for treating grade III AC separations, we hypothesize that more MLB team physicians would favor operative intervention treatment in professional baseball pitchers, as their vocation places higher demands on their shoulders.

MATERIALS AND METHODS

A questionnaire (Appendix A) was distributed to the team physicians of all 30 MLB teams. In addition to surgeon demographics, including age, years in practice, and years of taking care of an MLB team, the initial section of the questionnaire asked orthopedic surgeons how they would treat a theoretical starting pitcher who sustained a grade III AC joint separation of the dominant throwing arm 1 week prior to the start of the season. Physicians who preferred nonoperative treatment were asked whether they would use an injection (and what type), as well as when they would allow the pitcher to start a progressive interval throwing program. Physicians who preferred operative treatment were asked to rank their indications for operating, what procedure they would use (eg, open vs arthroscopic or coracoclavicular ligament repair vs reconstruction), and whether the surgical intervention would include distal clavicle excision. Both groups of physicians were also asked if their preferred treatment would change if the injury were to occur at the end of the season.

The second portion of the questionnaire asked surgeons about their experience treating AC joint separations in both starting pitchers and position players, as well as to describe the long-term outcomes of their preferred treatment, including time to return to full clearance for pitching, whether their patients returned to their prior level of play, and whether these patients had full pain relief. Finally, physicians were asked if any of the nonoperatively treated players ultimately crossed over and required operative intervention.

Continue to: Statistics...

STATISTICS

Descriptive statistics were used for continuous variables, and frequencies were used for categorical variables. Linear regression was performed to determine the correlation between the physician’s training or experience in treating AC joint separations and their recommended treatment. Fischer’s exact test/chi-square analysis was used to compare categorical variables. All tests were conducted using 2-sided hypothesis testing with statistical significance set at P < .05. All statistical analyses were conducted with SPSS 21.0 software (IBM Corporation).

RESULTS

A total of 28 MLB team physicians completed the questionnaires from 18 of the 30 MLB teams. The average age of the responders was 50.5 years (range, 34-60 years), with an average of 18.2 years in practice (range, 2-30 years) and 10.8 years (range, 1-24 years) taking care of their current professional baseball team. About 82% of the team physicians completed a sports medicine fellowship. On average, physicians saw 16.6 (range, 5-50) grade III or higher AC joint separations per year, and operated on 4.6 (range, 0-10) per year.

Nonoperative treatment was the preferred treatment for a grade III AC joint separation in a starting professional baseball pitcher for the majority of team physicians (20/28). No correlation was observed between the physician’s age (P = .881), years in practice (P = .915), years taking care of their professional team (P = .989), percentage of practice focused on shoulders (P = .986), number of AC joint injuries seen (P = .325), or number of surgeries performed per year (P = .807) with the team physician’s preferred treatment. Compared to the proportion reported originally by McFarland and colleagues¹³ in 1997 (69%), there was no difference in the proportion of team physicians that recommended nonoperative treatment (P = 1).

If treating this injury nonoperatively, 46.4% of physicians would also use an injection, with orthobiologics (eg, platelet-rich plasma) as the most popular choice (Table 1). No consensus was provided on the timeframe to return pitchers back to a progressive interval throwing program; however, 46.67% of physicians would return pitchers 4 to 6 weeks after a nonoperatively treated injury, while 35.7% would return pitchers 7 to 12 weeks after the initial injury.

Table 1. Treatment Preferences of Grade III AC Separation by MLB Team Physicians

^aRespondents were allowed to choose more than 1 treatment in each category. ^bChosen as an adjunct treatment.

Abbreviations: AC, acromioclavicular; MLB, major league baseball.

Most physicians (64.3%) cited functional limitations as the most important reason for indicating operative treatment, followed by pain (21.4%), and a deformity (14.3%). About 65% preferred open coracoclavicular ligament reconstruction. No physician recommended the Weaver-Dunn procedure or use of hardware (eg, hook plate). Of those who preferred an operative intervention, 66.7% would also include a distal clavicle excision, which is significantly higher than the proportion reported by McFarland and colleagues¹³ (23%, P = .0170). About 90% of physicians would return pitchers to play >12 weeks after operative treatment.

Continue to: If the injury occurred at the end ...

If the injury occurred at the end of the season, 7 of the 20 orthopedists (35%) who recommended nonoperative treatment said they would change to an operative intervention. Eighteen of 28 responders would have the same algorithm for MLB position players. Team physicians were less likely to recommend operative intervention in position players due to less demand on the arm and increased ability to accommodate the injury by altering their throwing mechanics.

Eighteen (64%) of the team physicians had treated at least 1 professional pitcher with a grade III AC separation in his dominant arm, and 11 (39.3%) had treated >1. Collectively, team physicians had treated 15 professional pitchers operatively, and 51 nonoperatively; only 3 patients converted to operative intervention after a failed nonoperative treatment.

Of the pitchers treated operatively, 93.3% (14) of pitchers returned to their prior level of pitching. The 1 patient who failed to return to the same level of pitching retired instead of returning to play. About 80% (12) of the pitchers had full pain relief, and 93.3% (14) had full range of motion (ROM). The pitcher who failed to regain full ROM also had a concomitant rotator cuff repair. The only complication reported from an operative intervention was a pitcher who sustained a coracoid fracture 10 months postoperatively while throwing 100 mph. Of the pitchers treated nonoperatively, 96% returned to their prior level of pitching, 92.2% (47) had full complete pain relief when throwing, and 100% had full ROM. No differences were observed between the proportion of pitchers who returned to their prior level of pitching, regained full ROM, or had full pain relief in the operative and nonoperative groups (Table 2).

Table 2. Outcomes of Treatment of Grade III AC Separation in 58 Professional Baseball Players

Abbreviations: AC, acromioclavicular; ROM, range of motion.

DISCUSSION 

Controversy persists regarding the optimal management of acute grade III AC separations, with the current available evidence potentially suggesting better cosmetic and radiological results but no definite differences in clinical results.^1-6,17,18 In the absence of formal clinical practice guidelines, surgeons rely on their own experience or defer to the anecdotal experience of experts in the field. Our initial hypothesis was false in this survey of MLB team physicians taking care of overhead throwing athletes at the highest level. Our results demonstrate that despite improved techniques and an increased understanding of the pathophysiology of AC joint separations, conservative management is still the preferred treatment for acute grade III AC joint separations in professional baseball pitchers. The proportion of team physicians recommending nonoperative treatment in our series was essentially equivalent to the results reported by McFarland and colleagues¹³ in 1997, suggesting that the pendulum continues to favor conservative management initially. This status quo likely reflects both the dearth of literature suggesting a substantial benefit of acute operative repair, as well as the ability to accommodate with conservative measures after most grade III AC injuries, even at the highest level of athletic competition.

These results are also consistent with trends from the last few decades. In the 1970s, the overwhelming preference for treating an acute complete AC joint separation was surgical repair, with Powers and Bach¹⁰ reporting in a 1974 survey of 163 chairmen of orthopedic programs around the country that 91.5% advocated surgical treatment. However, surgical preference had reversed by the 1990s. Of the 187 chairmen and 59 team physicians surveyed by Cox¹⁹ in 1992, 72% and 86% respectively preferred nonoperative treatment in a theoretical 21-year-old athlete with a grade III AC separation. Nissen and Chatterjee²⁰ reported in 2007 on a survey of all American Orthopaedic Society for Sports Medicine surgeons (N = 577) and Accreditation Council for Graduate Medical Education orthopedic program residency directors (N = 87) that >80% of responders preferred conservative measures for this acute injury. The reversal of trends has also been corroborated by recent multicenter trials demonstrating no difference in clinical outcomes between operative and nonoperative treatment of high grade AC joint dislocations, albeit these patients were not all high level overhead throwing athletes.^17,18

Continue to: The trends in surgical interventions are notable...

The trends in surgical interventions are notable within the smaller subset of patients who are indicated for operative repair. Use of hardware and primary ligament repair, while popular in the surveys conducted in the 1970s¹⁰ and 1990s¹³ and even present in Nissen and Chatterjee’s²⁰ 2007 survey, were noticeably absent from our survey results, with the majority of respondents preferring open coracoclavicular ligament reconstruction. The role of distal clavicle excision has also expanded, from 23% of team physicians recommending it in 1997¹³ to 57% to 59% in Nissen and Chatterjee’s²⁰ 2007 survey, to 66.7% in our series. This trend is not surprising as several recent cadaveric biomechanical studies have demonstrated that not only do peak graft forces not increase significantly,²¹ the anterior-posterior and superior-inferior motion at the AC joint following ligament reconstruction is maintained despite resection of the lateral clavicle.²² Additionally, primary distal clavicle excision may prevent the development of post-traumatic arthritis at the AC joint and osteolysis of the distal clavicle as a possible pain generator in the future.²³ However, some respondents cautioned against performing a concomitant distal clavicle excision, as some biomechanical data demonstrate that resecting the distal clavicle may lead to increased horizontal translation at the AC joint despite intact superior and posterior AC capsules.²⁴ Professional baseball pitchers may also be more lax and thus prone to more instability. Primary repair or reconstruction may not always lead to complete pre-injury stability in these individuals. This subtle unrecognized instability is hard to diagnosis and may be a persistent source of pain; thus, adding a distal clavicle excision may actually exacerbate the instability.

The nuanced indications for operative intervention, such as the presence of associated lesions were not captured by our survey.²⁵ While most team physicians cited functional limitations as their most common reason for offering surgery, several MLB orthopedic surgeons also commented on evaluating the stability of the AC joint after a grade III injury, akin to the consensus statement from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee²⁶ in 2014 that diversified the Rockwood Grade III AC joint separation into its IIIA and IIIB classifications. The ISAKOS recommendations include initial conservative management and a second evaluation (both clinical and radiographic) for grade III lesions 3 to 6 weeks after the injury. However, as professional baseball is an incredibly profitable sport with an annual revenue approaching $9.5 billion²⁷ and pitching salaries up to $32.5 million in 2015, serious financial considerations must be given to players who wish to avoid undergoing delayed surgery.

This study has shortcomings typical of expert opinion papers. The retrospective nature of this study places the data at risk of recall bias. Objective data (eg, terminal ROM, pain relief, and return to play) were obtained from a retrospective chart review; however, no standard documentation or collection method was used given the number of surgeons involved and, thus, conclusions based on treatment outcomes are imperfect. Another major weakness of this survey is the relatively small number of patients and respondents. An a priori power analysis was not available, as this was a retrospective review. A comparative trial will be necessary to definitively support one treatment over another. Assuming a 95% return to play in the nonoperatively treated group, approximately 300 patients would be needed in a prospective 2-armed study with 80% power to detect a 10% reduction in the incidence of return to play using an alpha level of 0.05 and assuming no loss to follow-up. This sample size would be difficult to achieve in this patient population.

However, compared to past series,¹³ the number of professional baseball players treated by the collective experience of these MLB team physicians is the largest reported to date. As suggested above, the rarity of this condition in elite athletes precludes the ability to have matched controls to definitively determine the optimal treatment, which may explain the lack of difference in the return to play, ROM, and pain relief outcomes. Instead, we can only extrapolate based on the collective anecdotal experience of the MLB team physicians.

CONCLUSION

Despite advances in surgical technique and understanding of throwing mechanics, the majority of MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in a professional baseball pitcher. Open coracoclavicular ligament reconstruction was preferred for those who preferred operative intervention. An increasing number of orthopedic surgeons now consider a distal clavicle excision as an adjunct procedure.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

Despite advancements in surgical technique and understanding of throwing mechanics, controversy persists regarding the treatment of grade III acromioclavicular (AC) joint separations, particularly in throwing athletes. Twenty-eight major league baseball (MLB) orthopedic team physicians were surveyed to determine their definitive management of a grade III AC separation in the dominant arm of a professional baseball pitcher and their experience treating AC joint separations in starting pitchers and position players. Return-to-play outcomes were also evaluated. Twenty (71.4%) team physicians recommended nonoperative intervention compared to 8 (28.6%) who would have operated acutely. Eighteen (64.3%) team physicians had treated at least 1 professional pitcher with a grade III AC separation; 51 (77.3%) pitchers had been treated nonoperatively compared to 15 (22.7%) operatively. No difference was observed in the proportion of pitchers who returned to the same level of play (P = .54), had full, unrestricted range of motion (P = .23), or had full pain relief (P = .19) between the operatively and nonoperatively treated MLB pitchers. The majority (53.6%) of physicians would not include an injection if the injury was treated nonoperatively. Open coracoclavicular reconstruction (65.2%) was preferred for operative cases; 66.7% of surgeons would also include distal clavicle excision as an adjunct procedure. About 90% of physicians would return pitchers to throwing >12 weeks after surgery compared to after 4 to 6 weeks in nonoperatively treated cases. In conclusion, MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in professional pitchers. If operative intervention is required, ligament reconstruction with adjunct distal clavicle excision were the most commonly performed procedures.

Continue to: Despite advancements in surgucal technique...

Despite advancements in surgical technique and improved understanding of the physiology of throwing mechanics, controversy persists regarding the preferred treatment for grade III acromioclavicular (AC) joint separations.^1-6 Nonsurgical management has demonstrated return to prior function with fewer complications.⁷ However, there is a growing body of evidence demonstrating that surgical intervention is associated with more favorable outcomes⁸ and should be considered in patients who place high functional demands on their shoulders.⁹

The reported results on professional athletes in the literature remain ambivalent. Multiple small case reports/series have reported successful nonoperative treatment of elite athletes.^10-12 Not surprisingly, McFarland and colleagues¹³ reported in 1997 that 69% of major league baseball (MLB) team physicians preferred nonoperative treatment for a theoretical starting pitcher sustaining a grade III AC separation 1 week prior to the start of the season. In contrast, reports of an inability to throw at a pre-injury level are equally commonplace.^14,15 Nevertheless, all of these studies were limited to small cohorts, as the incidence of grade III AC separations in elite throwing athletes is relatively uncommon.^13,16

In this study, we re-evaluated the study performed by McFarland and colleagues¹³ in 1997 by surveying all active MLB team orthopedic surgeons. We asked them how they would treat a grade III AC separation in a starting professional baseball pitcher. The physicians were also asked about their personal experience evaluating outcomes in these elite athletes. Given our improved understanding of the anatomy, pathophysiology, and surgical techniques for treating grade III AC separations, we hypothesize that more MLB team physicians would favor operative intervention treatment in professional baseball pitchers, as their vocation places higher demands on their shoulders.

MATERIALS AND METHODS

A questionnaire (Appendix A) was distributed to the team physicians of all 30 MLB teams. In addition to surgeon demographics, including age, years in practice, and years of taking care of an MLB team, the initial section of the questionnaire asked orthopedic surgeons how they would treat a theoretical starting pitcher who sustained a grade III AC joint separation of the dominant throwing arm 1 week prior to the start of the season. Physicians who preferred nonoperative treatment were asked whether they would use an injection (and what type), as well as when they would allow the pitcher to start a progressive interval throwing program. Physicians who preferred operative treatment were asked to rank their indications for operating, what procedure they would use (eg, open vs arthroscopic or coracoclavicular ligament repair vs reconstruction), and whether the surgical intervention would include distal clavicle excision. Both groups of physicians were also asked if their preferred treatment would change if the injury were to occur at the end of the season.

The second portion of the questionnaire asked surgeons about their experience treating AC joint separations in both starting pitchers and position players, as well as to describe the long-term outcomes of their preferred treatment, including time to return to full clearance for pitching, whether their patients returned to their prior level of play, and whether these patients had full pain relief. Finally, physicians were asked if any of the nonoperatively treated players ultimately crossed over and required operative intervention.

Continue to: Statistics...

STATISTICS

Descriptive statistics were used for continuous variables, and frequencies were used for categorical variables. Linear regression was performed to determine the correlation between the physician’s training or experience in treating AC joint separations and their recommended treatment. Fischer’s exact test/chi-square analysis was used to compare categorical variables. All tests were conducted using 2-sided hypothesis testing with statistical significance set at P < .05. All statistical analyses were conducted with SPSS 21.0 software (IBM Corporation).

RESULTS

A total of 28 MLB team physicians completed the questionnaires from 18 of the 30 MLB teams. The average age of the responders was 50.5 years (range, 34-60 years), with an average of 18.2 years in practice (range, 2-30 years) and 10.8 years (range, 1-24 years) taking care of their current professional baseball team. About 82% of the team physicians completed a sports medicine fellowship. On average, physicians saw 16.6 (range, 5-50) grade III or higher AC joint separations per year, and operated on 4.6 (range, 0-10) per year.

Nonoperative treatment was the preferred treatment for a grade III AC joint separation in a starting professional baseball pitcher for the majority of team physicians (20/28). No correlation was observed between the physician’s age (P = .881), years in practice (P = .915), years taking care of their professional team (P = .989), percentage of practice focused on shoulders (P = .986), number of AC joint injuries seen (P = .325), or number of surgeries performed per year (P = .807) with the team physician’s preferred treatment. Compared to the proportion reported originally by McFarland and colleagues¹³ in 1997 (69%), there was no difference in the proportion of team physicians that recommended nonoperative treatment (P = 1).

If treating this injury nonoperatively, 46.4% of physicians would also use an injection, with orthobiologics (eg, platelet-rich plasma) as the most popular choice (Table 1). No consensus was provided on the timeframe to return pitchers back to a progressive interval throwing program; however, 46.67% of physicians would return pitchers 4 to 6 weeks after a nonoperatively treated injury, while 35.7% would return pitchers 7 to 12 weeks after the initial injury.

Table 1. Treatment Preferences of Grade III AC Separation by MLB Team Physicians

^aRespondents were allowed to choose more than 1 treatment in each category. ^bChosen as an adjunct treatment.

Abbreviations: AC, acromioclavicular; MLB, major league baseball.

Most physicians (64.3%) cited functional limitations as the most important reason for indicating operative treatment, followed by pain (21.4%), and a deformity (14.3%). About 65% preferred open coracoclavicular ligament reconstruction. No physician recommended the Weaver-Dunn procedure or use of hardware (eg, hook plate). Of those who preferred an operative intervention, 66.7% would also include a distal clavicle excision, which is significantly higher than the proportion reported by McFarland and colleagues¹³ (23%, P = .0170). About 90% of physicians would return pitchers to play >12 weeks after operative treatment.

Continue to: If the injury occurred at the end ...

If the injury occurred at the end of the season, 7 of the 20 orthopedists (35%) who recommended nonoperative treatment said they would change to an operative intervention. Eighteen of 28 responders would have the same algorithm for MLB position players. Team physicians were less likely to recommend operative intervention in position players due to less demand on the arm and increased ability to accommodate the injury by altering their throwing mechanics.

Eighteen (64%) of the team physicians had treated at least 1 professional pitcher with a grade III AC separation in his dominant arm, and 11 (39.3%) had treated >1. Collectively, team physicians had treated 15 professional pitchers operatively, and 51 nonoperatively; only 3 patients converted to operative intervention after a failed nonoperative treatment.

Of the pitchers treated operatively, 93.3% (14) of pitchers returned to their prior level of pitching. The 1 patient who failed to return to the same level of pitching retired instead of returning to play. About 80% (12) of the pitchers had full pain relief, and 93.3% (14) had full range of motion (ROM). The pitcher who failed to regain full ROM also had a concomitant rotator cuff repair. The only complication reported from an operative intervention was a pitcher who sustained a coracoid fracture 10 months postoperatively while throwing 100 mph. Of the pitchers treated nonoperatively, 96% returned to their prior level of pitching, 92.2% (47) had full complete pain relief when throwing, and 100% had full ROM. No differences were observed between the proportion of pitchers who returned to their prior level of pitching, regained full ROM, or had full pain relief in the operative and nonoperative groups (Table 2).

Table 2. Outcomes of Treatment of Grade III AC Separation in 58 Professional Baseball Players

Abbreviations: AC, acromioclavicular; ROM, range of motion.

DISCUSSION 

Controversy persists regarding the optimal management of acute grade III AC separations, with the current available evidence potentially suggesting better cosmetic and radiological results but no definite differences in clinical results.^1-6,17,18 In the absence of formal clinical practice guidelines, surgeons rely on their own experience or defer to the anecdotal experience of experts in the field. Our initial hypothesis was false in this survey of MLB team physicians taking care of overhead throwing athletes at the highest level. Our results demonstrate that despite improved techniques and an increased understanding of the pathophysiology of AC joint separations, conservative management is still the preferred treatment for acute grade III AC joint separations in professional baseball pitchers. The proportion of team physicians recommending nonoperative treatment in our series was essentially equivalent to the results reported by McFarland and colleagues¹³ in 1997, suggesting that the pendulum continues to favor conservative management initially. This status quo likely reflects both the dearth of literature suggesting a substantial benefit of acute operative repair, as well as the ability to accommodate with conservative measures after most grade III AC injuries, even at the highest level of athletic competition.

These results are also consistent with trends from the last few decades. In the 1970s, the overwhelming preference for treating an acute complete AC joint separation was surgical repair, with Powers and Bach¹⁰ reporting in a 1974 survey of 163 chairmen of orthopedic programs around the country that 91.5% advocated surgical treatment. However, surgical preference had reversed by the 1990s. Of the 187 chairmen and 59 team physicians surveyed by Cox¹⁹ in 1992, 72% and 86% respectively preferred nonoperative treatment in a theoretical 21-year-old athlete with a grade III AC separation. Nissen and Chatterjee²⁰ reported in 2007 on a survey of all American Orthopaedic Society for Sports Medicine surgeons (N = 577) and Accreditation Council for Graduate Medical Education orthopedic program residency directors (N = 87) that >80% of responders preferred conservative measures for this acute injury. The reversal of trends has also been corroborated by recent multicenter trials demonstrating no difference in clinical outcomes between operative and nonoperative treatment of high grade AC joint dislocations, albeit these patients were not all high level overhead throwing athletes.^17,18

Continue to: The trends in surgical interventions are notable...

The trends in surgical interventions are notable within the smaller subset of patients who are indicated for operative repair. Use of hardware and primary ligament repair, while popular in the surveys conducted in the 1970s¹⁰ and 1990s¹³ and even present in Nissen and Chatterjee’s²⁰ 2007 survey, were noticeably absent from our survey results, with the majority of respondents preferring open coracoclavicular ligament reconstruction. The role of distal clavicle excision has also expanded, from 23% of team physicians recommending it in 1997¹³ to 57% to 59% in Nissen and Chatterjee’s²⁰ 2007 survey, to 66.7% in our series. This trend is not surprising as several recent cadaveric biomechanical studies have demonstrated that not only do peak graft forces not increase significantly,²¹ the anterior-posterior and superior-inferior motion at the AC joint following ligament reconstruction is maintained despite resection of the lateral clavicle.²² Additionally, primary distal clavicle excision may prevent the development of post-traumatic arthritis at the AC joint and osteolysis of the distal clavicle as a possible pain generator in the future.²³ However, some respondents cautioned against performing a concomitant distal clavicle excision, as some biomechanical data demonstrate that resecting the distal clavicle may lead to increased horizontal translation at the AC joint despite intact superior and posterior AC capsules.²⁴ Professional baseball pitchers may also be more lax and thus prone to more instability. Primary repair or reconstruction may not always lead to complete pre-injury stability in these individuals. This subtle unrecognized instability is hard to diagnosis and may be a persistent source of pain; thus, adding a distal clavicle excision may actually exacerbate the instability.

The nuanced indications for operative intervention, such as the presence of associated lesions were not captured by our survey.²⁵ While most team physicians cited functional limitations as their most common reason for offering surgery, several MLB orthopedic surgeons also commented on evaluating the stability of the AC joint after a grade III injury, akin to the consensus statement from the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Upper Extremity Committee²⁶ in 2014 that diversified the Rockwood Grade III AC joint separation into its IIIA and IIIB classifications. The ISAKOS recommendations include initial conservative management and a second evaluation (both clinical and radiographic) for grade III lesions 3 to 6 weeks after the injury. However, as professional baseball is an incredibly profitable sport with an annual revenue approaching $9.5 billion²⁷ and pitching salaries up to $32.5 million in 2015, serious financial considerations must be given to players who wish to avoid undergoing delayed surgery.

This study has shortcomings typical of expert opinion papers. The retrospective nature of this study places the data at risk of recall bias. Objective data (eg, terminal ROM, pain relief, and return to play) were obtained from a retrospective chart review; however, no standard documentation or collection method was used given the number of surgeons involved and, thus, conclusions based on treatment outcomes are imperfect. Another major weakness of this survey is the relatively small number of patients and respondents. An a priori power analysis was not available, as this was a retrospective review. A comparative trial will be necessary to definitively support one treatment over another. Assuming a 95% return to play in the nonoperatively treated group, approximately 300 patients would be needed in a prospective 2-armed study with 80% power to detect a 10% reduction in the incidence of return to play using an alpha level of 0.05 and assuming no loss to follow-up. This sample size would be difficult to achieve in this patient population.

However, compared to past series,¹³ the number of professional baseball players treated by the collective experience of these MLB team physicians is the largest reported to date. As suggested above, the rarity of this condition in elite athletes precludes the ability to have matched controls to definitively determine the optimal treatment, which may explain the lack of difference in the return to play, ROM, and pain relief outcomes. Instead, we can only extrapolate based on the collective anecdotal experience of the MLB team physicians.

CONCLUSION

Despite advances in surgical technique and understanding of throwing mechanics, the majority of MLB team physicians preferred nonoperative management for an acute grade III AC joint separation in a professional baseball pitcher. Open coracoclavicular ligament reconstruction was preferred for those who preferred operative intervention. An increasing number of orthopedic surgeons now consider a distal clavicle excision as an adjunct procedure.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

The traditional technique for patella fracture fixation utilizes prominent hardware. Prominent hardware use, however, results in a high rate of reoperation for symptomatic implant removal. This biomechanical study evaluates the effectiveness of a novel patella fixation technique that minimizes implant prominence.

Patellar transverse osteotomies were created in 13 pairs of cadaveric knees. Paired knees were assigned to either standard fixation (SF) using cannulated partially threaded screws and stainless steel wire tension band, or buried fixation (BF) using headless compression screws with a No. 2 FiberWire tension band and a No. 5 FiberWire cerclage suture. Quadriceps tendons were cyclically loaded to full extension followed by load to failure. The gap across the fracture site, stiffness, and load to failure were measured.

The differences in stiffness and load to failure between the 2 groups were not statistically significant. During cyclic loading, significantly greater gapping was observed across the fracture site in the BF group compared with SF group (P < .05).

Both constructs failed under loads that exceeded typical loads experienced during the postoperative rehabilitation period. Nevertheless, the BF technique demonstrated larger gap formation and a reduced load to failure than the SF technique. Further clinical studies are therefore underway to determine whether the use of constructs with decreased stability but increased patient comfort could improve clinical outcomes and reduce reoperation rates.

Continue to: Patella fractures are common...

Patella fractures are common injuries that can cause considerable disability to the knee extensor apparatus.^1-3 Transverse patella fractures are the most common fracture pattern associated with patella fractures.{Harrell, 2003 #3}² Given that the patella plays a crucial role in knee extensor biomechanics, its proper integrity is vital for physiological knee motion and ambulation.⁴ Traditionally, patella fractures with >2 mm of displacement have been managed with cannulated screws or Kirschner wires (K-wires) and a stainless-steel wire tension band.^5-9 The goal in the treatment of patellar fractures is to reduce fracture fragments accurately and to minimize additional insults to the articular cartilage.¹⁰

Despite advances in surgical protocols and acceptable radiographic outcomes, functional impairment remains common after the treatment of patella fractures. Functional impairment includes knee pain, screw head pain, implant removal, wire breakage, and patella baja.¹ The need for implant removal is one of the most common complications following the open reduction internal fixation of patella fractures.^2,11 The subcutaneous and exposed nature of the patella in conjunction with soft tissue irritation resulting from standard fixation (SF) predisposes the patient toward prominence and discomfort with the retained implant. Although nonunion rates are low, the rate of implant removal can reach as high as 52%.^2,10-12 To overcome some of these complications, we designed a novel buried fixation (BF) method for the treatment of transverse fractures. Our method minimizes the amount of exposed implant to improve patient comfort and potentially reduce the need for future implant removal. These effects are achieved by using headless compression screws and nonabsorbable sutures to attenuate the soft tissue irritation associated with traditional fixation.¹³ While our novel technique has demonstrated improved clinical results, it has not been tested biomechanically against a traditional fixation technique. Therefore, this study aims to evaluate and compare the structural integrity of our novel BF technique with that of the standard technique that uses cannulated screws and wire tension band. We hypothesized that the stability provided by our technique would be similar to that provided by SF for transverse patella fractures.

MATERIALS AND METHODS

SPECIMEN PREPARATION

Thirteen matched pairs of fresh-frozen human cadaveric knees were obtained from a Cedars-Sinai approved tissue bank. Specimens were cut midfemur and were intact to the foot. Legs with major structural bony or ligamentous abnormalities, extensor mechanism disruption, or septic knees were excluded from testing. To assess the bone quality of each specimen prior to testing, dual-energy X-ray absorptiometry was performed using a GE Lunar iDXA scanner (GE Healthcare). Specimens were stored at −30°C and thawed at room temperature for 24 hours prior to biomechanical testing.

A midline anterior approach to the patella was performed, and the extensor retinaculum, quadriceps tendon, and patellar tendon were exposed. A digital caliper was used to measure the craniocaudal and mediolateral dimensions of the patella, and a transverse osteotomy (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association [AO/OTA] type 34-C1) was created at the midway point between superior and inferior poles by using an oscillating saw. The retinaculum was then incised to the level of the midaxial line of the femur. One leg from each matched pair was allocated to the SF group, and the other was allocated to the BF group. Left and right legs were alternately assigned to each group to ensure that laterality was balanced between the 2 groups.

SURGICAL TECHNIQUE

The repair of the specimens in the SF group involved the use of 2 parallel 4.0-mm partially threaded cannulated screws (Acumed) and an 18-gauge monofilament steel wire (Ethicon) in a figure-eight tension band (Figure 1A). The repair of the specimens in the BF group involved the use of 2 parallel standard Acutrak headless compression screws (Acumed), a No. 2 FiberWire (Arthrex) in a figure-eight tension band, and a No. 5 FiberWire (Arthrex) was applied as cerclage around the patella (Figure 1B).

Continue to: Mechanical testing...

MECHANICAL TESTING

Mechanical testing was performed on a biaxial 370.02 Bionix Testing System (MTS Systems Corp.). The femur was rigidly and horizontally secured to a custom-built test frame, and the lower leg was left free to move. The quadriceps tendon was secured in a freeze clamp and was attached to the MTS actuator for loading via a pulley system such that raising the actuator was translated into a simulated quadriceps extensor force.

A differential variable reluctance transducer (DVRT) (Lord MicroStrain) was placed across the osteotomy site to measure the distraction, or gap, across the fracture line. The minimum load to full extension for each specimen was then determined under a slow, controlled increase in load until the leg was in a fully extended position. Any distraction across the fracture line during the initial loading phase was determined by using digital calipers. The specimen was then subjected to a preconditioning phase with 10 cycles from 0 N to full extension under the previously determined load, which was applied at the rate of 5 N/s. Meanwhile, displacement across the fracture site was recorded via the DVRT. Following the preconditioning phase, each specimen was then tested to failure in displacement control at the rate of 1.5 mm/s. Failure was defined as implant failure (screw pullout) or DVRT gapping across the osteotomy site >3 mm.^10,14

Outcome measures included stiffness (N/mm), which was calculated as the slope of the linear change in load from full extension to failure vs DVRT displacement during the final loading phase; failure load (N); gapping (mm) across the osteotomy site at each cycle during the preconditioning phase; and failure mode (pullout vs >3.0 mm gap).

STATISTICAL ANALYSIS

An a priori power analysis revealed that 13 knees per group would be required to obtain an α of 0.05 and a power of 0.80. This calculation was based on a 20% difference in fracture displacement calculated by using the standard deviation and mean previously reported for cannulated screws with nonabsorbable sutures.¹⁴

Means and standard deviations for all dependent outcome measures were computed and compared across the independent measure of fixation type (BF vs SF) through repeated measures Analysis of variance (ANOVA-GLM, SAS 9.3, SAS Institute, Inc.) after controlling for bone mineral density (BMD), gender, and age. Multivariate repeated-measures ANOVA with Tukey's studentized range was applied to cyclic gap data. The mode of failure was compared across fixation type (BF vs SF) for matched data using McNemar’s test. Intracorrelations were computed and examined over all data and separately on the basis of screw fixation type (BF vs SF). All tests were considered statistically significant when P < .05.

Continue to: Results...

RESULTS

Specimen donors were 46% (6/13) male with an average age of 78.5 years (±13.77; range, 56-91 years) and 54% (7/13) female with an average age of 76.57 years (±14.37; range, 59-102 years). Average BMD was significantly lower in female (0.71 ± 0.18) than in male specimens (1.15 ± 0.33) (P < .05).

The average load to full extension across all specimens was 272 N (±54; range, 160-360 N) and was well balanced across matched pairs (270 ± 56 N for BF and 273 ± 54 N for SF). Of the 13 BF specimens, 4 experienced distraction across the fracture line during the determination of the minimum load to full extension. This initial pretest gap was measured with digital calipers (average, 1.5 mm; range, 0.90-1.85 mm) and added as an offset to the respective DVRT displacement data recorded during testing.

The total number of specimens included in the displacement data calculations decreased from 13 to 11 per group because DVRT data were not recorded during cyclic loading for 1 specimen and were considered unreliable in another. The maximum displacement measured across the fracture site during cyclic loading was significantly higher in the BF (0.94 ± 1.21) group than in the SF group (0.19 ± 0.26) as shown in the Table. The average slope of the gap per cycle for each specimen was calculated and compared between the BF and SF groups. The BF group demonstrated a significantly greater increase in gap per cycle than the SF group (Figure 2). Stiffness during load to failure was calculated for all but 1 specimen that did not display any measurable displacement during the final loading cycle. The average final stiffness and failure load between the BF and SF groups were not significantly different (Table). An equal number of specimens in both groups failed through gapping (6/13) and pullout (7/13).

Table. Means and Standard Deviations of the Main Outcome Measures

^aIndicates statistical significance (P < .05).

Abbreviation: NS, not significant.

Failure load was significantly positively correlated with BMD (R = 0.62, P < .001) when all specimens were grouped together. When analyzed separately, the SF group was significantly correlated with BMD (P < .01), whereas the BF group had a marginally significant correlation (P = .06) with BMD (Figure 3). In both groups, BMD was positively correlated with stiffness and negatively correlated with gapping. Neither of these trends, however, was significant.

Continue to: Discussion...

DISCUSSION

We proposed a novel BF technique for the treatment of noncomminuted transverse patella fractures. Our technique utilizes headless cannulated compression screws and nonabsorbable suture tension bands. We then biomechanically compared our proposed technique with an established fixation technique that uses partially threaded cannulated screws and stainless steel wire tension bands. We hypothesized that the mechanical response of the BF technique to cyclic and failure loading would be similar to that of the SF technique. Our results demonstrate a significant increase in gap formation across the fracture site among knees and an overall reduced load to failure in the BF group (Figure 2). Whether these inferior results manifest clinically is not yet established. Both constructs could withstand forces that are typically experienced during the postoperative period. Given the high rate of symptomatic implant removal associated with the traditional technique, the low-profile buried technique might be an attractive alternative that provides increased patient comfort but may require an extended period of postoperative protection against bony ingrowths.

Patellar fixation constructs that use a combination of cannulated screws and a wire tension band provide the best resistance to patella fracture displacement when compared with screws or wires alone.^4,15 Although this combination is biomechanically favorable, the steel wire often causes the painful irritation of the surrounding soft tissues and can break or migrate, thus increasing the rates of implant removal surgery to as high as 52%.^4,10,12,15 We developed our novel BF technique, which uses headless compression screws and a No. 2 FiberWire tension band, to address the high rates of reoperation and patient dissatisfaction associated with the SF technique.

Headless compression screws have been successfully used in the reduction and fixation of scaphoid fractures and sesamoid fractures.^16,17 The pull-out strengths of these screws are comparable with those of other commonly used screws, such as Twinfix and Herbert-Whipple screws.¹⁶ Similarly, the strength of a No. 5 FiberWire is comparable with that of an 18-gauge stainless-steel wire.^14,18 Several studies have also obtained good outcomes with nonmetallic constructs that use nonabsorbable sutures alone.^19,20 In this study, we utilized a No. 2 FiberWire as the tension band. The use of the No. 2 FiberWire facilitated threading through headless cannulated screws and created a low-profile knot. However, the use of thin FiberWire, despite a No. 5 FiberWire cerclage, likely contributed to the increase in distraction across the fracture.

The highest patellofemoral joint reaction force during level walking is approximately 35 kg (half body weight), which is equivalent to 350 N.^15,21,22 This force is similar to the average cyclic load used in this experiment (272 ± 54 N). Gapping increased in the BF group but did not reach the defined failure value of 3 mm, and the ultimate load to failure was relatively high across both groups (SF, 1123 N; BF, 973 N). These results suggest that both fixation methods can withstand the typical patellofemoral joint forces that are experienced during the postoperative period.⁴ In addition, in a clinical setting, patients are placed in hinged knee braces for at least 2 weeks to limit their flexion angle and to allow for healing and bony ingrowth. Postoperative knee-brace protection presumably increases the overall strength of the fixation.

The number of specimens (n = 26) evaluated in this study was greater than that used in other biomechanical patella fracture studies.¹⁴ Furthermore, none of our specimens were reused. Our study design was further strengthened given that fellowship-trained trauma surgeons performed all surgical procedures. Finally, the data collection and analysis of numerous clinically relevant factors, such as BMD, age, and cyclical loading, contributed to the comprehensive description of each technique with respect to patient-specific criteria.

Similar to all cadaveric studies, our data only represent the immediate postoperative condition and does not represent any healing that would occur during postoperative rehabilitation. Postoperative knee-brace protection and bone healing across the fracture site would likely strengthen both constructs in a clinical setting. In addition, the average age of our specimens is 77.5 years, and therefore does not best represent the age range (20-50 years) of the typical adult population affected by patella fractures.^3,23,24 Finally, postsurgical reduction was confirmed through visual inspection and not through fluoroscopy as in a clinical setting. Radiographic images were obtained after each experiment only to confirm screw placement post facto (Figures 4A, 4B).

CONCLUSION

This study demonstrates the utility of a novel BF technique. Nevertheless, the proposed technique exhibited increased gapping and a lower load to failure than the current gold standard. The significance of these inferior results in clinical and functional settings has not been established. The proposed BF technique may be an appealing alternative to the SF technique given its low profile and potential to reduce the rates of future implant removal. Further studies on the long-term outcomes of patients treated through the BF technique are currently under way and will ultimately determine the utility of the proposed construct.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

The traditional technique for patella fracture fixation utilizes prominent hardware. Prominent hardware use, however, results in a high rate of reoperation for symptomatic implant removal. This biomechanical study evaluates the effectiveness of a novel patella fixation technique that minimizes implant prominence.

Patellar transverse osteotomies were created in 13 pairs of cadaveric knees. Paired knees were assigned to either standard fixation (SF) using cannulated partially threaded screws and stainless steel wire tension band, or buried fixation (BF) using headless compression screws with a No. 2 FiberWire tension band and a No. 5 FiberWire cerclage suture. Quadriceps tendons were cyclically loaded to full extension followed by load to failure. The gap across the fracture site, stiffness, and load to failure were measured.

The differences in stiffness and load to failure between the 2 groups were not statistically significant. During cyclic loading, significantly greater gapping was observed across the fracture site in the BF group compared with SF group (P < .05).

Both constructs failed under loads that exceeded typical loads experienced during the postoperative rehabilitation period. Nevertheless, the BF technique demonstrated larger gap formation and a reduced load to failure than the SF technique. Further clinical studies are therefore underway to determine whether the use of constructs with decreased stability but increased patient comfort could improve clinical outcomes and reduce reoperation rates.

Continue to: Patella fractures are common...

Patella fractures are common injuries that can cause considerable disability to the knee extensor apparatus.^1-3 Transverse patella fractures are the most common fracture pattern associated with patella fractures.{Harrell, 2003 #3}² Given that the patella plays a crucial role in knee extensor biomechanics, its proper integrity is vital for physiological knee motion and ambulation.⁴ Traditionally, patella fractures with >2 mm of displacement have been managed with cannulated screws or Kirschner wires (K-wires) and a stainless-steel wire tension band.^5-9 The goal in the treatment of patellar fractures is to reduce fracture fragments accurately and to minimize additional insults to the articular cartilage.¹⁰

Despite advances in surgical protocols and acceptable radiographic outcomes, functional impairment remains common after the treatment of patella fractures. Functional impairment includes knee pain, screw head pain, implant removal, wire breakage, and patella baja.¹ The need for implant removal is one of the most common complications following the open reduction internal fixation of patella fractures.^2,11 The subcutaneous and exposed nature of the patella in conjunction with soft tissue irritation resulting from standard fixation (SF) predisposes the patient toward prominence and discomfort with the retained implant. Although nonunion rates are low, the rate of implant removal can reach as high as 52%.^2,10-12 To overcome some of these complications, we designed a novel buried fixation (BF) method for the treatment of transverse fractures. Our method minimizes the amount of exposed implant to improve patient comfort and potentially reduce the need for future implant removal. These effects are achieved by using headless compression screws and nonabsorbable sutures to attenuate the soft tissue irritation associated with traditional fixation.¹³ While our novel technique has demonstrated improved clinical results, it has not been tested biomechanically against a traditional fixation technique. Therefore, this study aims to evaluate and compare the structural integrity of our novel BF technique with that of the standard technique that uses cannulated screws and wire tension band. We hypothesized that the stability provided by our technique would be similar to that provided by SF for transverse patella fractures.

MATERIALS AND METHODS

SPECIMEN PREPARATION

Thirteen matched pairs of fresh-frozen human cadaveric knees were obtained from a Cedars-Sinai approved tissue bank. Specimens were cut midfemur and were intact to the foot. Legs with major structural bony or ligamentous abnormalities, extensor mechanism disruption, or septic knees were excluded from testing. To assess the bone quality of each specimen prior to testing, dual-energy X-ray absorptiometry was performed using a GE Lunar iDXA scanner (GE Healthcare). Specimens were stored at −30°C and thawed at room temperature for 24 hours prior to biomechanical testing.

A midline anterior approach to the patella was performed, and the extensor retinaculum, quadriceps tendon, and patellar tendon were exposed. A digital caliper was used to measure the craniocaudal and mediolateral dimensions of the patella, and a transverse osteotomy (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association [AO/OTA] type 34-C1) was created at the midway point between superior and inferior poles by using an oscillating saw. The retinaculum was then incised to the level of the midaxial line of the femur. One leg from each matched pair was allocated to the SF group, and the other was allocated to the BF group. Left and right legs were alternately assigned to each group to ensure that laterality was balanced between the 2 groups.

SURGICAL TECHNIQUE

The repair of the specimens in the SF group involved the use of 2 parallel 4.0-mm partially threaded cannulated screws (Acumed) and an 18-gauge monofilament steel wire (Ethicon) in a figure-eight tension band (Figure 1A). The repair of the specimens in the BF group involved the use of 2 parallel standard Acutrak headless compression screws (Acumed), a No. 2 FiberWire (Arthrex) in a figure-eight tension band, and a No. 5 FiberWire (Arthrex) was applied as cerclage around the patella (Figure 1B).

Continue to: Mechanical testing...

MECHANICAL TESTING

Mechanical testing was performed on a biaxial 370.02 Bionix Testing System (MTS Systems Corp.). The femur was rigidly and horizontally secured to a custom-built test frame, and the lower leg was left free to move. The quadriceps tendon was secured in a freeze clamp and was attached to the MTS actuator for loading via a pulley system such that raising the actuator was translated into a simulated quadriceps extensor force.

A differential variable reluctance transducer (DVRT) (Lord MicroStrain) was placed across the osteotomy site to measure the distraction, or gap, across the fracture line. The minimum load to full extension for each specimen was then determined under a slow, controlled increase in load until the leg was in a fully extended position. Any distraction across the fracture line during the initial loading phase was determined by using digital calipers. The specimen was then subjected to a preconditioning phase with 10 cycles from 0 N to full extension under the previously determined load, which was applied at the rate of 5 N/s. Meanwhile, displacement across the fracture site was recorded via the DVRT. Following the preconditioning phase, each specimen was then tested to failure in displacement control at the rate of 1.5 mm/s. Failure was defined as implant failure (screw pullout) or DVRT gapping across the osteotomy site >3 mm.^10,14

Outcome measures included stiffness (N/mm), which was calculated as the slope of the linear change in load from full extension to failure vs DVRT displacement during the final loading phase; failure load (N); gapping (mm) across the osteotomy site at each cycle during the preconditioning phase; and failure mode (pullout vs >3.0 mm gap).

STATISTICAL ANALYSIS

An a priori power analysis revealed that 13 knees per group would be required to obtain an α of 0.05 and a power of 0.80. This calculation was based on a 20% difference in fracture displacement calculated by using the standard deviation and mean previously reported for cannulated screws with nonabsorbable sutures.¹⁴

Means and standard deviations for all dependent outcome measures were computed and compared across the independent measure of fixation type (BF vs SF) through repeated measures Analysis of variance (ANOVA-GLM, SAS 9.3, SAS Institute, Inc.) after controlling for bone mineral density (BMD), gender, and age. Multivariate repeated-measures ANOVA with Tukey's studentized range was applied to cyclic gap data. The mode of failure was compared across fixation type (BF vs SF) for matched data using McNemar’s test. Intracorrelations were computed and examined over all data and separately on the basis of screw fixation type (BF vs SF). All tests were considered statistically significant when P < .05.

Continue to: Results...

RESULTS

Specimen donors were 46% (6/13) male with an average age of 78.5 years (±13.77; range, 56-91 years) and 54% (7/13) female with an average age of 76.57 years (±14.37; range, 59-102 years). Average BMD was significantly lower in female (0.71 ± 0.18) than in male specimens (1.15 ± 0.33) (P < .05).

The average load to full extension across all specimens was 272 N (±54; range, 160-360 N) and was well balanced across matched pairs (270 ± 56 N for BF and 273 ± 54 N for SF). Of the 13 BF specimens, 4 experienced distraction across the fracture line during the determination of the minimum load to full extension. This initial pretest gap was measured with digital calipers (average, 1.5 mm; range, 0.90-1.85 mm) and added as an offset to the respective DVRT displacement data recorded during testing.

The total number of specimens included in the displacement data calculations decreased from 13 to 11 per group because DVRT data were not recorded during cyclic loading for 1 specimen and were considered unreliable in another. The maximum displacement measured across the fracture site during cyclic loading was significantly higher in the BF (0.94 ± 1.21) group than in the SF group (0.19 ± 0.26) as shown in the Table. The average slope of the gap per cycle for each specimen was calculated and compared between the BF and SF groups. The BF group demonstrated a significantly greater increase in gap per cycle than the SF group (Figure 2). Stiffness during load to failure was calculated for all but 1 specimen that did not display any measurable displacement during the final loading cycle. The average final stiffness and failure load between the BF and SF groups were not significantly different (Table). An equal number of specimens in both groups failed through gapping (6/13) and pullout (7/13).

Table. Means and Standard Deviations of the Main Outcome Measures

^aIndicates statistical significance (P < .05).

Abbreviation: NS, not significant.

Failure load was significantly positively correlated with BMD (R = 0.62, P < .001) when all specimens were grouped together. When analyzed separately, the SF group was significantly correlated with BMD (P < .01), whereas the BF group had a marginally significant correlation (P = .06) with BMD (Figure 3). In both groups, BMD was positively correlated with stiffness and negatively correlated with gapping. Neither of these trends, however, was significant.

Continue to: Discussion...

DISCUSSION

We proposed a novel BF technique for the treatment of noncomminuted transverse patella fractures. Our technique utilizes headless cannulated compression screws and nonabsorbable suture tension bands. We then biomechanically compared our proposed technique with an established fixation technique that uses partially threaded cannulated screws and stainless steel wire tension bands. We hypothesized that the mechanical response of the BF technique to cyclic and failure loading would be similar to that of the SF technique. Our results demonstrate a significant increase in gap formation across the fracture site among knees and an overall reduced load to failure in the BF group (Figure 2). Whether these inferior results manifest clinically is not yet established. Both constructs could withstand forces that are typically experienced during the postoperative period. Given the high rate of symptomatic implant removal associated with the traditional technique, the low-profile buried technique might be an attractive alternative that provides increased patient comfort but may require an extended period of postoperative protection against bony ingrowths.

Patellar fixation constructs that use a combination of cannulated screws and a wire tension band provide the best resistance to patella fracture displacement when compared with screws or wires alone.^4,15 Although this combination is biomechanically favorable, the steel wire often causes the painful irritation of the surrounding soft tissues and can break or migrate, thus increasing the rates of implant removal surgery to as high as 52%.^4,10,12,15 We developed our novel BF technique, which uses headless compression screws and a No. 2 FiberWire tension band, to address the high rates of reoperation and patient dissatisfaction associated with the SF technique.

Headless compression screws have been successfully used in the reduction and fixation of scaphoid fractures and sesamoid fractures.^16,17 The pull-out strengths of these screws are comparable with those of other commonly used screws, such as Twinfix and Herbert-Whipple screws.¹⁶ Similarly, the strength of a No. 5 FiberWire is comparable with that of an 18-gauge stainless-steel wire.^14,18 Several studies have also obtained good outcomes with nonmetallic constructs that use nonabsorbable sutures alone.^19,20 In this study, we utilized a No. 2 FiberWire as the tension band. The use of the No. 2 FiberWire facilitated threading through headless cannulated screws and created a low-profile knot. However, the use of thin FiberWire, despite a No. 5 FiberWire cerclage, likely contributed to the increase in distraction across the fracture.

The highest patellofemoral joint reaction force during level walking is approximately 35 kg (half body weight), which is equivalent to 350 N.^15,21,22 This force is similar to the average cyclic load used in this experiment (272 ± 54 N). Gapping increased in the BF group but did not reach the defined failure value of 3 mm, and the ultimate load to failure was relatively high across both groups (SF, 1123 N; BF, 973 N). These results suggest that both fixation methods can withstand the typical patellofemoral joint forces that are experienced during the postoperative period.⁴ In addition, in a clinical setting, patients are placed in hinged knee braces for at least 2 weeks to limit their flexion angle and to allow for healing and bony ingrowth. Postoperative knee-brace protection presumably increases the overall strength of the fixation.

The number of specimens (n = 26) evaluated in this study was greater than that used in other biomechanical patella fracture studies.¹⁴ Furthermore, none of our specimens were reused. Our study design was further strengthened given that fellowship-trained trauma surgeons performed all surgical procedures. Finally, the data collection and analysis of numerous clinically relevant factors, such as BMD, age, and cyclical loading, contributed to the comprehensive description of each technique with respect to patient-specific criteria.

Similar to all cadaveric studies, our data only represent the immediate postoperative condition and does not represent any healing that would occur during postoperative rehabilitation. Postoperative knee-brace protection and bone healing across the fracture site would likely strengthen both constructs in a clinical setting. In addition, the average age of our specimens is 77.5 years, and therefore does not best represent the age range (20-50 years) of the typical adult population affected by patella fractures.^3,23,24 Finally, postsurgical reduction was confirmed through visual inspection and not through fluoroscopy as in a clinical setting. Radiographic images were obtained after each experiment only to confirm screw placement post facto (Figures 4A, 4B).

CONCLUSION

This study demonstrates the utility of a novel BF technique. Nevertheless, the proposed technique exhibited increased gapping and a lower load to failure than the current gold standard. The significance of these inferior results in clinical and functional settings has not been established. The proposed BF technique may be an appealing alternative to the SF technique given its low profile and potential to reduce the rates of future implant removal. Further studies on the long-term outcomes of patients treated through the BF technique are currently under way and will ultimately determine the utility of the proposed construct.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

The traditional technique for patella fracture fixation utilizes prominent hardware. Prominent hardware use, however, results in a high rate of reoperation for symptomatic implant removal. This biomechanical study evaluates the effectiveness of a novel patella fixation technique that minimizes implant prominence.

Patellar transverse osteotomies were created in 13 pairs of cadaveric knees. Paired knees were assigned to either standard fixation (SF) using cannulated partially threaded screws and stainless steel wire tension band, or buried fixation (BF) using headless compression screws with a No. 2 FiberWire tension band and a No. 5 FiberWire cerclage suture. Quadriceps tendons were cyclically loaded to full extension followed by load to failure. The gap across the fracture site, stiffness, and load to failure were measured.

The differences in stiffness and load to failure between the 2 groups were not statistically significant. During cyclic loading, significantly greater gapping was observed across the fracture site in the BF group compared with SF group (P < .05).

Both constructs failed under loads that exceeded typical loads experienced during the postoperative rehabilitation period. Nevertheless, the BF technique demonstrated larger gap formation and a reduced load to failure than the SF technique. Further clinical studies are therefore underway to determine whether the use of constructs with decreased stability but increased patient comfort could improve clinical outcomes and reduce reoperation rates.

Continue to: Patella fractures are common...

Patella fractures are common injuries that can cause considerable disability to the knee extensor apparatus.^1-3 Transverse patella fractures are the most common fracture pattern associated with patella fractures.{Harrell, 2003 #3}² Given that the patella plays a crucial role in knee extensor biomechanics, its proper integrity is vital for physiological knee motion and ambulation.⁴ Traditionally, patella fractures with >2 mm of displacement have been managed with cannulated screws or Kirschner wires (K-wires) and a stainless-steel wire tension band.^5-9 The goal in the treatment of patellar fractures is to reduce fracture fragments accurately and to minimize additional insults to the articular cartilage.¹⁰

Despite advances in surgical protocols and acceptable radiographic outcomes, functional impairment remains common after the treatment of patella fractures. Functional impairment includes knee pain, screw head pain, implant removal, wire breakage, and patella baja.¹ The need for implant removal is one of the most common complications following the open reduction internal fixation of patella fractures.^2,11 The subcutaneous and exposed nature of the patella in conjunction with soft tissue irritation resulting from standard fixation (SF) predisposes the patient toward prominence and discomfort with the retained implant. Although nonunion rates are low, the rate of implant removal can reach as high as 52%.^2,10-12 To overcome some of these complications, we designed a novel buried fixation (BF) method for the treatment of transverse fractures. Our method minimizes the amount of exposed implant to improve patient comfort and potentially reduce the need for future implant removal. These effects are achieved by using headless compression screws and nonabsorbable sutures to attenuate the soft tissue irritation associated with traditional fixation.¹³ While our novel technique has demonstrated improved clinical results, it has not been tested biomechanically against a traditional fixation technique. Therefore, this study aims to evaluate and compare the structural integrity of our novel BF technique with that of the standard technique that uses cannulated screws and wire tension band. We hypothesized that the stability provided by our technique would be similar to that provided by SF for transverse patella fractures.

MATERIALS AND METHODS

SPECIMEN PREPARATION

Thirteen matched pairs of fresh-frozen human cadaveric knees were obtained from a Cedars-Sinai approved tissue bank. Specimens were cut midfemur and were intact to the foot. Legs with major structural bony or ligamentous abnormalities, extensor mechanism disruption, or septic knees were excluded from testing. To assess the bone quality of each specimen prior to testing, dual-energy X-ray absorptiometry was performed using a GE Lunar iDXA scanner (GE Healthcare). Specimens were stored at −30°C and thawed at room temperature for 24 hours prior to biomechanical testing.

A midline anterior approach to the patella was performed, and the extensor retinaculum, quadriceps tendon, and patellar tendon were exposed. A digital caliper was used to measure the craniocaudal and mediolateral dimensions of the patella, and a transverse osteotomy (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association [AO/OTA] type 34-C1) was created at the midway point between superior and inferior poles by using an oscillating saw. The retinaculum was then incised to the level of the midaxial line of the femur. One leg from each matched pair was allocated to the SF group, and the other was allocated to the BF group. Left and right legs were alternately assigned to each group to ensure that laterality was balanced between the 2 groups.

SURGICAL TECHNIQUE

The repair of the specimens in the SF group involved the use of 2 parallel 4.0-mm partially threaded cannulated screws (Acumed) and an 18-gauge monofilament steel wire (Ethicon) in a figure-eight tension band (Figure 1A). The repair of the specimens in the BF group involved the use of 2 parallel standard Acutrak headless compression screws (Acumed), a No. 2 FiberWire (Arthrex) in a figure-eight tension band, and a No. 5 FiberWire (Arthrex) was applied as cerclage around the patella (Figure 1B).

Continue to: Mechanical testing...

MECHANICAL TESTING

Mechanical testing was performed on a biaxial 370.02 Bionix Testing System (MTS Systems Corp.). The femur was rigidly and horizontally secured to a custom-built test frame, and the lower leg was left free to move. The quadriceps tendon was secured in a freeze clamp and was attached to the MTS actuator for loading via a pulley system such that raising the actuator was translated into a simulated quadriceps extensor force.

A differential variable reluctance transducer (DVRT) (Lord MicroStrain) was placed across the osteotomy site to measure the distraction, or gap, across the fracture line. The minimum load to full extension for each specimen was then determined under a slow, controlled increase in load until the leg was in a fully extended position. Any distraction across the fracture line during the initial loading phase was determined by using digital calipers. The specimen was then subjected to a preconditioning phase with 10 cycles from 0 N to full extension under the previously determined load, which was applied at the rate of 5 N/s. Meanwhile, displacement across the fracture site was recorded via the DVRT. Following the preconditioning phase, each specimen was then tested to failure in displacement control at the rate of 1.5 mm/s. Failure was defined as implant failure (screw pullout) or DVRT gapping across the osteotomy site >3 mm.^10,14

Outcome measures included stiffness (N/mm), which was calculated as the slope of the linear change in load from full extension to failure vs DVRT displacement during the final loading phase; failure load (N); gapping (mm) across the osteotomy site at each cycle during the preconditioning phase; and failure mode (pullout vs >3.0 mm gap).

STATISTICAL ANALYSIS

An a priori power analysis revealed that 13 knees per group would be required to obtain an α of 0.05 and a power of 0.80. This calculation was based on a 20% difference in fracture displacement calculated by using the standard deviation and mean previously reported for cannulated screws with nonabsorbable sutures.¹⁴

Means and standard deviations for all dependent outcome measures were computed and compared across the independent measure of fixation type (BF vs SF) through repeated measures Analysis of variance (ANOVA-GLM, SAS 9.3, SAS Institute, Inc.) after controlling for bone mineral density (BMD), gender, and age. Multivariate repeated-measures ANOVA with Tukey's studentized range was applied to cyclic gap data. The mode of failure was compared across fixation type (BF vs SF) for matched data using McNemar’s test. Intracorrelations were computed and examined over all data and separately on the basis of screw fixation type (BF vs SF). All tests were considered statistically significant when P < .05.

Continue to: Results...

RESULTS

Specimen donors were 46% (6/13) male with an average age of 78.5 years (±13.77; range, 56-91 years) and 54% (7/13) female with an average age of 76.57 years (±14.37; range, 59-102 years). Average BMD was significantly lower in female (0.71 ± 0.18) than in male specimens (1.15 ± 0.33) (P < .05).

The average load to full extension across all specimens was 272 N (±54; range, 160-360 N) and was well balanced across matched pairs (270 ± 56 N for BF and 273 ± 54 N for SF). Of the 13 BF specimens, 4 experienced distraction across the fracture line during the determination of the minimum load to full extension. This initial pretest gap was measured with digital calipers (average, 1.5 mm; range, 0.90-1.85 mm) and added as an offset to the respective DVRT displacement data recorded during testing.

The total number of specimens included in the displacement data calculations decreased from 13 to 11 per group because DVRT data were not recorded during cyclic loading for 1 specimen and were considered unreliable in another. The maximum displacement measured across the fracture site during cyclic loading was significantly higher in the BF (0.94 ± 1.21) group than in the SF group (0.19 ± 0.26) as shown in the Table. The average slope of the gap per cycle for each specimen was calculated and compared between the BF and SF groups. The BF group demonstrated a significantly greater increase in gap per cycle than the SF group (Figure 2). Stiffness during load to failure was calculated for all but 1 specimen that did not display any measurable displacement during the final loading cycle. The average final stiffness and failure load between the BF and SF groups were not significantly different (Table). An equal number of specimens in both groups failed through gapping (6/13) and pullout (7/13).

Table. Means and Standard Deviations of the Main Outcome Measures

^aIndicates statistical significance (P < .05).

Abbreviation: NS, not significant.

Failure load was significantly positively correlated with BMD (R = 0.62, P < .001) when all specimens were grouped together. When analyzed separately, the SF group was significantly correlated with BMD (P < .01), whereas the BF group had a marginally significant correlation (P = .06) with BMD (Figure 3). In both groups, BMD was positively correlated with stiffness and negatively correlated with gapping. Neither of these trends, however, was significant.

Continue to: Discussion...

DISCUSSION

We proposed a novel BF technique for the treatment of noncomminuted transverse patella fractures. Our technique utilizes headless cannulated compression screws and nonabsorbable suture tension bands. We then biomechanically compared our proposed technique with an established fixation technique that uses partially threaded cannulated screws and stainless steel wire tension bands. We hypothesized that the mechanical response of the BF technique to cyclic and failure loading would be similar to that of the SF technique. Our results demonstrate a significant increase in gap formation across the fracture site among knees and an overall reduced load to failure in the BF group (Figure 2). Whether these inferior results manifest clinically is not yet established. Both constructs could withstand forces that are typically experienced during the postoperative period. Given the high rate of symptomatic implant removal associated with the traditional technique, the low-profile buried technique might be an attractive alternative that provides increased patient comfort but may require an extended period of postoperative protection against bony ingrowths.

Patellar fixation constructs that use a combination of cannulated screws and a wire tension band provide the best resistance to patella fracture displacement when compared with screws or wires alone.^4,15 Although this combination is biomechanically favorable, the steel wire often causes the painful irritation of the surrounding soft tissues and can break or migrate, thus increasing the rates of implant removal surgery to as high as 52%.^4,10,12,15 We developed our novel BF technique, which uses headless compression screws and a No. 2 FiberWire tension band, to address the high rates of reoperation and patient dissatisfaction associated with the SF technique.

Headless compression screws have been successfully used in the reduction and fixation of scaphoid fractures and sesamoid fractures.^16,17 The pull-out strengths of these screws are comparable with those of other commonly used screws, such as Twinfix and Herbert-Whipple screws.¹⁶ Similarly, the strength of a No. 5 FiberWire is comparable with that of an 18-gauge stainless-steel wire.^14,18 Several studies have also obtained good outcomes with nonmetallic constructs that use nonabsorbable sutures alone.^19,20 In this study, we utilized a No. 2 FiberWire as the tension band. The use of the No. 2 FiberWire facilitated threading through headless cannulated screws and created a low-profile knot. However, the use of thin FiberWire, despite a No. 5 FiberWire cerclage, likely contributed to the increase in distraction across the fracture.

The highest patellofemoral joint reaction force during level walking is approximately 35 kg (half body weight), which is equivalent to 350 N.^15,21,22 This force is similar to the average cyclic load used in this experiment (272 ± 54 N). Gapping increased in the BF group but did not reach the defined failure value of 3 mm, and the ultimate load to failure was relatively high across both groups (SF, 1123 N; BF, 973 N). These results suggest that both fixation methods can withstand the typical patellofemoral joint forces that are experienced during the postoperative period.⁴ In addition, in a clinical setting, patients are placed in hinged knee braces for at least 2 weeks to limit their flexion angle and to allow for healing and bony ingrowth. Postoperative knee-brace protection presumably increases the overall strength of the fixation.

The number of specimens (n = 26) evaluated in this study was greater than that used in other biomechanical patella fracture studies.¹⁴ Furthermore, none of our specimens were reused. Our study design was further strengthened given that fellowship-trained trauma surgeons performed all surgical procedures. Finally, the data collection and analysis of numerous clinically relevant factors, such as BMD, age, and cyclical loading, contributed to the comprehensive description of each technique with respect to patient-specific criteria.

Similar to all cadaveric studies, our data only represent the immediate postoperative condition and does not represent any healing that would occur during postoperative rehabilitation. Postoperative knee-brace protection and bone healing across the fracture site would likely strengthen both constructs in a clinical setting. In addition, the average age of our specimens is 77.5 years, and therefore does not best represent the age range (20-50 years) of the typical adult population affected by patella fractures.^3,23,24 Finally, postsurgical reduction was confirmed through visual inspection and not through fluoroscopy as in a clinical setting. Radiographic images were obtained after each experiment only to confirm screw placement post facto (Figures 4A, 4B).

CONCLUSION

This study demonstrates the utility of a novel BF technique. Nevertheless, the proposed technique exhibited increased gapping and a lower load to failure than the current gold standard. The significance of these inferior results in clinical and functional settings has not been established. The proposed BF technique may be an appealing alternative to the SF technique given its low profile and potential to reduce the rates of future implant removal. Further studies on the long-term outcomes of patients treated through the BF technique are currently under way and will ultimately determine the utility of the proposed construct.

This paper will be judged for the Resident Writer’s Award.

ANSWER

The radiograph shows an avulsion fracture of the right iliac crest. While the patient does have a growth plate in this location, there is asymmetry between the right and left sides.

Pelvic avulsion fractures can be easy to overlook and are often misdiagnosed as strains. Providers must remember that the pelvis serves as an insertion site for multiple muscles; in both adolescent and adult patients, certain activities (eg, sprinting, jumping, kicking) can increase tension and result in a bone avulsion. Affected patients typically report a popping sensation, pain with range of motion, and point tenderness over the fracture.

Avulsion fractures can usually be identified on x-ray; CT and MRI are used only when definitive diagnosis is unclear. Treatment consists of conservative management—rest, protected weight bearing, and physical therapy. Surgery is typically reserved for those with > 2 cm displacement of the fracture fragment.

In athletes, a gradual return to sports is advised, with full participation at four to 12 weeks postinjury. Possible complications include recurrent symptoms, prolonged healing time, nonunion, malunion, or hip weakness.

This patient was placed on crutches with non-weight-bearing status for one week. She used OTC pain medication as needed. The patient completed a four-week course of physical therapy and returned to full weight-bearing status. After six weeks, the patient had returned to full activity with pain-free range of motion and full strength.

ANSWER

The radiograph shows an avulsion fracture of the right iliac crest. While the patient does have a growth plate in this location, there is asymmetry between the right and left sides.

Pelvic avulsion fractures can be easy to overlook and are often misdiagnosed as strains. Providers must remember that the pelvis serves as an insertion site for multiple muscles; in both adolescent and adult patients, certain activities (eg, sprinting, jumping, kicking) can increase tension and result in a bone avulsion. Affected patients typically report a popping sensation, pain with range of motion, and point tenderness over the fracture.

Avulsion fractures can usually be identified on x-ray; CT and MRI are used only when definitive diagnosis is unclear. Treatment consists of conservative management—rest, protected weight bearing, and physical therapy. Surgery is typically reserved for those with > 2 cm displacement of the fracture fragment.

In athletes, a gradual return to sports is advised, with full participation at four to 12 weeks postinjury. Possible complications include recurrent symptoms, prolonged healing time, nonunion, malunion, or hip weakness.

This patient was placed on crutches with non-weight-bearing status for one week. She used OTC pain medication as needed. The patient completed a four-week course of physical therapy and returned to full weight-bearing status. After six weeks, the patient had returned to full activity with pain-free range of motion and full strength.

ANSWER

The radiograph shows an avulsion fracture of the right iliac crest. While the patient does have a growth plate in this location, there is asymmetry between the right and left sides.

Pelvic avulsion fractures can be easy to overlook and are often misdiagnosed as strains. Providers must remember that the pelvis serves as an insertion site for multiple muscles; in both adolescent and adult patients, certain activities (eg, sprinting, jumping, kicking) can increase tension and result in a bone avulsion. Affected patients typically report a popping sensation, pain with range of motion, and point tenderness over the fracture.

Avulsion fractures can usually be identified on x-ray; CT and MRI are used only when definitive diagnosis is unclear. Treatment consists of conservative management—rest, protected weight bearing, and physical therapy. Surgery is typically reserved for those with > 2 cm displacement of the fracture fragment.

In athletes, a gradual return to sports is advised, with full participation at four to 12 weeks postinjury. Possible complications include recurrent symptoms, prolonged healing time, nonunion, malunion, or hip weakness.

This patient was placed on crutches with non-weight-bearing status for one week. She used OTC pain medication as needed. The patient completed a four-week course of physical therapy and returned to full weight-bearing status. After six weeks, the patient had returned to full activity with pain-free range of motion and full strength.

ABSTRACT

An increasing interest focuses on the rates and risk factors for hospital readmission. However, little is known regarding the readmission following total shoulder arthroplasty (TSA). This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA. Patients undergoing TSA (anatomic or reverse) as part of the American College of Surgeons National Surgical Quality Improvement Program in 2011 to 2013 were identified. The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. Using multivariate regression, demographic and comorbidity factors were tested for independent association with readmission. Finally, the reasons for readmission were characterized. A total of 3627 patients were identified. Among the admitted patients, 93 (2.56%) were readmitted within 30 days of surgery. The independent risk factors for readmission included old age (for age 60-69 years, relative risk [RR] = 1.6; for age 70-79 years, RR = 2.3; for age ≥80 years, RR = 23.1; P = .042), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission comprised pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%). Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at higher risk for readmission and should be counseled and monitored accordingly.

Continue to: Total shoulder arthroplasty...

Total shoulder arthroplasty (TSA) is performed with increasing frequency in the United States and is considered to be cost-effective.^1-4 Following the procedure, patients generally achieve shoulder function and pain relief.^5-8 Despite the success of the procedure, the growing literature on TSA has also reported rates of complications between 3.6% and 25% of the treated patients.^9-16

In recent years, an increasing interest has focused on the rates and risk factors for unplanned hospital readmissions; these variables may not only reflect the quality of patient care but also result in considerable costs to the healthcare system. For instance, among Medicare patients, readmissions within 30 days of discharge occur in almost 20% of cases, costing $17.4 billion per year.¹⁷ Readmission rates increasingly factor into hospital performance metrics and reimbursement, including the Hospital Readmissions Reduction Program of the Patient Protection and Affordable Care Act that reduces Centers for Medicare and Medicaid Services payments to hospitals with high 30-day readmission rates.¹⁸

To date, only a few studies have evaluated readmission following TSA, with 30- to 90-day readmission rates ranging from 4.5% to 7.3%.^19-23 These studies comprised single institution series^20,22 and analyses of administrative databases.^19,21,23 Most studies have shown that readmission occurs more often for medical than surgical reasons, with surgical reasons most commonly including infection and dislocation.^19-23 However, only limited analyses have been conducted regarding risk factors for readmission.^21,23 To date and to our knowledge, no study has investigated reasons for readmission following TSA using nationwide data.

This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA in the United States using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

METHODS

DATA SOURCE

The NSQIP database was utilized to address the study purpose. NSQIP is a nationwide prospective surgical registry established by the American College of Surgeons and reports data from academic and community hospitals across the United States.²⁴ Patients undertaking surgery at these centers are followed by the surgical clinical reviewers at the participating NSQIP sites prospectively for 30 days following the procedure to record complications including readmission. Preoperative and surgical data, such as demographics, medical comorbid diseases, and operative time, are also included. Previous studies have analyzed the complications of various orthopedic surgeries using the NSQIP data.^14,16,25-30

DATA COLLECTION

We retrospectively identified from NSQIP the patients who underwent primary TSA (anatomic or reverse) in 2013 to 2014. The timeframe 2013 to 2014 was used because NSQIP only began recording reasons for readmission in 2013. The inclusion criteria were as follows: Current Procedural Terminology (CPT) code for TSA (23472); preoperative diagnosis according to the International Classification of Diseases, Ninth Revision (ICD-9) codes 714.0, 715.11, 715.31, 715.91, 715.21, 715.89, 716.xx 718.xx, 719.xx, 726.x, 727.xx, and 733.41 (where x is a wild card digit); and no missing demographic, comorbidity, or outcome data. Anatomic and reverse TSA were analyzed together because they share the same CPT code, and the NSQIP database prevents searching by the ICD-9 procedure code.

The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. The reasons for readmission in this 30-day period were only available in 2013 and were determined using the ICD-9 diagnosis codes. Patient demographics were recorded for use in identifying potential risk factors for readmission; the demographic data included sex, age, smoking status, body mass index (BMI), and comorbidities, including end-stage renal disease, dyspnea on exertion, congestive heart failure, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD).

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.

RESTULTS

A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.

Table 1. Patient Population

Abbreviation: COPD, chronic obstructive pulmonary disease.

In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).

Table 2. Bivariate Analysis of Risk Factors for Readmission

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).

Table 3. Independent Risk Factors for Readmission on Multivariate Analysis

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

Continue to: Table 4...

The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission included pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%) (Table 4).

Table 4. Reasons for Readmission

DISCUSSION

Our analysis of 3042 TSAs from the NSQIP database suggests that unplanned readmission to the hospital occurs following about 1 in 40 cases of TSA. The study also suggests that the most common reasons for readmission encompass pneumonia, dislocation, pulmonary embolism, and surgical site infection. Old age, male sex, anemia, and dependent functional status serve as risk factors for readmission, and patients with such factors should be counseled and monitored accordingly.

In recent years, an increasing emphasis has centered on reducing rates of hospital readmission, with programs such as the Hospital Readmissions Reduction Program of the Affordable Care Act cutting reimbursements for hospitals with high 30-day readmission rates.^17,18 To date, only a few studies have evaluated the reasons for readmission and readmission rates for TSA.^19-23 Initial reports consisted of single-institution TSA registry reviews. For example, Mahoney and colleagues²⁰ retrospectively evaluated shoulder arthroplasty procedures at their institution to document the readmission rates, finding a 5.9% readmission rate at 30 days. Readmission occurred more frequently in the first 30 days following discharge than in the 30- to 90-day period, with the most common reasons for readmission including medical complications, infection, and dislocation. Streubel and colleagues²² evaluated reoperation rates from their institution’s TSA registry, finding a 0.6% reoperation rate for primary TSA at 30 days and 1.5% for revision TSA. Instability and infection were the most common indications for reoperation. Our findings confirm these single-institution results and demonstrate their application to a nationwide sample of TSA, not just to high-volume academic centers. We similarly observed that dislocation, surgical site infection, and medical complications (mostly pneumonia and pulmonary embolism) were common causes of readmission, and that the 30-day readmission rate was about 1 in 40.

Several authors have since used statewide databases to analyze and determine risk factors for readmission following TSA. Lyman and colleagues¹⁹ used the New York State Database to show that higher hospital TSA surgical volume was associated with a lower rate of readmission when age and comorbidities were controlled for in a multivariate model. Old age was also associated with an increased readmission rate in their multivariate analysis, but comorbidities (as measured by the Charlson comorbidity index) presented a nonsignificant associative trend. These authors opted not to determine specific causes of readmission. Schairer and colleagues²¹ used State Inpatient Databases from 7 states, finding a 90-day readmission rate of 7.3%, 82% of which were due to medical complications and 18% of which were due to surgical complications (mostly infection and dislocation). Their multivariate regression revealed that male sex, reverse TSA, Medicaid insurance, patients discharged to inpatient rehabilitation or nursing facilities, medical comorbidities, and low-volume TSA hospitals were associated with readmission. Zhang and colleagues²³ used the same source to show that the 90-day readmission rate reached 14% for surgically treated proximal humerus fractures and higher for patients who underwent open reduction internal fixation, were female, were African American, were discharged to a nursing facility, possessed Medicaid insurance, or experienced medical comorbidities. Most recently, Basques and colleagues³¹ analyzed 1505 TSA cases from 2011 and 2012 in the NSQIP database, finding a 3.3% rate of readmission, with heart disease and hypertension as risk factors for readmission. Although the limitations of the NSQIP database prevented us from analyzing surgeon and hospital TSA volume or reverse vs anatomic TSA, our results confirm that the findings from statewide database studies apply to the United States nationwide NSQIP database. Old patient age, male sex, and medical comorbidities (anemia and dependent functional status) are independent risk factors for TSA readmission. We identified pneumonia, dislocation, pulmonary embolism, and surgical site infection as the most common reasons for readmission.

This study features several limitations that should be considered when interpreting the results. Anatomic and reverse TSA share a CPT code and were not separated using NSQIP data. A number of studies have reported that reverse TSA may place patients at higher risk for readmission;^20,21 however, confounding by other patient factors could play a role in this finding. The 30-day timeframe for readmission is another potential limitation; however, this timeframe is frequently used in other studies and is the relevant timeframe for the reduced reimbursement penalties from the Hospital Readmissions Reduction Program of the Affordable Care Act.¹⁸ Furthermore, the NSQIP database contains no information on surgeon or hospital TSA volume, which is a result of safeguards for patient and provider privacy. Additionally, readmission data were only available for 2011 to 2013, with causes of readmission only present in 2013. Although provided with such current information, we cannot analyze readmission trends over time, such as in response to the Affordable Care Act of 2010. Finally, although NSQIP surgical clinical reviewers strive to identify readmissions to other hospitals during their reviews of outpatient medical records, proportions of these readmissions are possibly missed. Therefore, our 30-day readmission rate may slightly underestimate the true rate.

Despite these limitations, the NSQIP database offers a unique opportunity to examine risk factors and reasons for readmission following TSA. The prior literature on readmission following TSA stemmed either from limited samples or administrative data, which feature known limitations.³² By utilizing a large, prospective, non-administrative, nationwide sample, our findings are probably both more reliable and generalizable to the country as a whole.

CONCLUSION

Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at a higher risk for readmission and should be counseled and monitored accordingly.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

An increasing interest focuses on the rates and risk factors for hospital readmission. However, little is known regarding the readmission following total shoulder arthroplasty (TSA). This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA. Patients undergoing TSA (anatomic or reverse) as part of the American College of Surgeons National Surgical Quality Improvement Program in 2011 to 2013 were identified. The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. Using multivariate regression, demographic and comorbidity factors were tested for independent association with readmission. Finally, the reasons for readmission were characterized. A total of 3627 patients were identified. Among the admitted patients, 93 (2.56%) were readmitted within 30 days of surgery. The independent risk factors for readmission included old age (for age 60-69 years, relative risk [RR] = 1.6; for age 70-79 years, RR = 2.3; for age ≥80 years, RR = 23.1; P = .042), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission comprised pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%). Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at higher risk for readmission and should be counseled and monitored accordingly.

Continue to: Total shoulder arthroplasty...

Total shoulder arthroplasty (TSA) is performed with increasing frequency in the United States and is considered to be cost-effective.^1-4 Following the procedure, patients generally achieve shoulder function and pain relief.^5-8 Despite the success of the procedure, the growing literature on TSA has also reported rates of complications between 3.6% and 25% of the treated patients.^9-16

In recent years, an increasing interest has focused on the rates and risk factors for unplanned hospital readmissions; these variables may not only reflect the quality of patient care but also result in considerable costs to the healthcare system. For instance, among Medicare patients, readmissions within 30 days of discharge occur in almost 20% of cases, costing $17.4 billion per year.¹⁷ Readmission rates increasingly factor into hospital performance metrics and reimbursement, including the Hospital Readmissions Reduction Program of the Patient Protection and Affordable Care Act that reduces Centers for Medicare and Medicaid Services payments to hospitals with high 30-day readmission rates.¹⁸

To date, only a few studies have evaluated readmission following TSA, with 30- to 90-day readmission rates ranging from 4.5% to 7.3%.^19-23 These studies comprised single institution series^20,22 and analyses of administrative databases.^19,21,23 Most studies have shown that readmission occurs more often for medical than surgical reasons, with surgical reasons most commonly including infection and dislocation.^19-23 However, only limited analyses have been conducted regarding risk factors for readmission.^21,23 To date and to our knowledge, no study has investigated reasons for readmission following TSA using nationwide data.

This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA in the United States using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

METHODS

DATA SOURCE

The NSQIP database was utilized to address the study purpose. NSQIP is a nationwide prospective surgical registry established by the American College of Surgeons and reports data from academic and community hospitals across the United States.²⁴ Patients undertaking surgery at these centers are followed by the surgical clinical reviewers at the participating NSQIP sites prospectively for 30 days following the procedure to record complications including readmission. Preoperative and surgical data, such as demographics, medical comorbid diseases, and operative time, are also included. Previous studies have analyzed the complications of various orthopedic surgeries using the NSQIP data.^14,16,25-30

DATA COLLECTION

We retrospectively identified from NSQIP the patients who underwent primary TSA (anatomic or reverse) in 2013 to 2014. The timeframe 2013 to 2014 was used because NSQIP only began recording reasons for readmission in 2013. The inclusion criteria were as follows: Current Procedural Terminology (CPT) code for TSA (23472); preoperative diagnosis according to the International Classification of Diseases, Ninth Revision (ICD-9) codes 714.0, 715.11, 715.31, 715.91, 715.21, 715.89, 716.xx 718.xx, 719.xx, 726.x, 727.xx, and 733.41 (where x is a wild card digit); and no missing demographic, comorbidity, or outcome data. Anatomic and reverse TSA were analyzed together because they share the same CPT code, and the NSQIP database prevents searching by the ICD-9 procedure code.

The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. The reasons for readmission in this 30-day period were only available in 2013 and were determined using the ICD-9 diagnosis codes. Patient demographics were recorded for use in identifying potential risk factors for readmission; the demographic data included sex, age, smoking status, body mass index (BMI), and comorbidities, including end-stage renal disease, dyspnea on exertion, congestive heart failure, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD).

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.

RESTULTS

A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.

Table 1. Patient Population

Abbreviation: COPD, chronic obstructive pulmonary disease.

In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).

Table 2. Bivariate Analysis of Risk Factors for Readmission

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).

Table 3. Independent Risk Factors for Readmission on Multivariate Analysis

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

Continue to: Table 4...

The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission included pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%) (Table 4).

Table 4. Reasons for Readmission

DISCUSSION

Our analysis of 3042 TSAs from the NSQIP database suggests that unplanned readmission to the hospital occurs following about 1 in 40 cases of TSA. The study also suggests that the most common reasons for readmission encompass pneumonia, dislocation, pulmonary embolism, and surgical site infection. Old age, male sex, anemia, and dependent functional status serve as risk factors for readmission, and patients with such factors should be counseled and monitored accordingly.

In recent years, an increasing emphasis has centered on reducing rates of hospital readmission, with programs such as the Hospital Readmissions Reduction Program of the Affordable Care Act cutting reimbursements for hospitals with high 30-day readmission rates.^17,18 To date, only a few studies have evaluated the reasons for readmission and readmission rates for TSA.^19-23 Initial reports consisted of single-institution TSA registry reviews. For example, Mahoney and colleagues²⁰ retrospectively evaluated shoulder arthroplasty procedures at their institution to document the readmission rates, finding a 5.9% readmission rate at 30 days. Readmission occurred more frequently in the first 30 days following discharge than in the 30- to 90-day period, with the most common reasons for readmission including medical complications, infection, and dislocation. Streubel and colleagues²² evaluated reoperation rates from their institution’s TSA registry, finding a 0.6% reoperation rate for primary TSA at 30 days and 1.5% for revision TSA. Instability and infection were the most common indications for reoperation. Our findings confirm these single-institution results and demonstrate their application to a nationwide sample of TSA, not just to high-volume academic centers. We similarly observed that dislocation, surgical site infection, and medical complications (mostly pneumonia and pulmonary embolism) were common causes of readmission, and that the 30-day readmission rate was about 1 in 40.

Several authors have since used statewide databases to analyze and determine risk factors for readmission following TSA. Lyman and colleagues¹⁹ used the New York State Database to show that higher hospital TSA surgical volume was associated with a lower rate of readmission when age and comorbidities were controlled for in a multivariate model. Old age was also associated with an increased readmission rate in their multivariate analysis, but comorbidities (as measured by the Charlson comorbidity index) presented a nonsignificant associative trend. These authors opted not to determine specific causes of readmission. Schairer and colleagues²¹ used State Inpatient Databases from 7 states, finding a 90-day readmission rate of 7.3%, 82% of which were due to medical complications and 18% of which were due to surgical complications (mostly infection and dislocation). Their multivariate regression revealed that male sex, reverse TSA, Medicaid insurance, patients discharged to inpatient rehabilitation or nursing facilities, medical comorbidities, and low-volume TSA hospitals were associated with readmission. Zhang and colleagues²³ used the same source to show that the 90-day readmission rate reached 14% for surgically treated proximal humerus fractures and higher for patients who underwent open reduction internal fixation, were female, were African American, were discharged to a nursing facility, possessed Medicaid insurance, or experienced medical comorbidities. Most recently, Basques and colleagues³¹ analyzed 1505 TSA cases from 2011 and 2012 in the NSQIP database, finding a 3.3% rate of readmission, with heart disease and hypertension as risk factors for readmission. Although the limitations of the NSQIP database prevented us from analyzing surgeon and hospital TSA volume or reverse vs anatomic TSA, our results confirm that the findings from statewide database studies apply to the United States nationwide NSQIP database. Old patient age, male sex, and medical comorbidities (anemia and dependent functional status) are independent risk factors for TSA readmission. We identified pneumonia, dislocation, pulmonary embolism, and surgical site infection as the most common reasons for readmission.

This study features several limitations that should be considered when interpreting the results. Anatomic and reverse TSA share a CPT code and were not separated using NSQIP data. A number of studies have reported that reverse TSA may place patients at higher risk for readmission;^20,21 however, confounding by other patient factors could play a role in this finding. The 30-day timeframe for readmission is another potential limitation; however, this timeframe is frequently used in other studies and is the relevant timeframe for the reduced reimbursement penalties from the Hospital Readmissions Reduction Program of the Affordable Care Act.¹⁸ Furthermore, the NSQIP database contains no information on surgeon or hospital TSA volume, which is a result of safeguards for patient and provider privacy. Additionally, readmission data were only available for 2011 to 2013, with causes of readmission only present in 2013. Although provided with such current information, we cannot analyze readmission trends over time, such as in response to the Affordable Care Act of 2010. Finally, although NSQIP surgical clinical reviewers strive to identify readmissions to other hospitals during their reviews of outpatient medical records, proportions of these readmissions are possibly missed. Therefore, our 30-day readmission rate may slightly underestimate the true rate.

Despite these limitations, the NSQIP database offers a unique opportunity to examine risk factors and reasons for readmission following TSA. The prior literature on readmission following TSA stemmed either from limited samples or administrative data, which feature known limitations.³² By utilizing a large, prospective, non-administrative, nationwide sample, our findings are probably both more reliable and generalizable to the country as a whole.

CONCLUSION

Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at a higher risk for readmission and should be counseled and monitored accordingly.

This paper will be judged for the Resident Writer’s Award.

ABSTRACT

An increasing interest focuses on the rates and risk factors for hospital readmission. However, little is known regarding the readmission following total shoulder arthroplasty (TSA). This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA. Patients undergoing TSA (anatomic or reverse) as part of the American College of Surgeons National Surgical Quality Improvement Program in 2011 to 2013 were identified. The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. Using multivariate regression, demographic and comorbidity factors were tested for independent association with readmission. Finally, the reasons for readmission were characterized. A total of 3627 patients were identified. Among the admitted patients, 93 (2.56%) were readmitted within 30 days of surgery. The independent risk factors for readmission included old age (for age 60-69 years, relative risk [RR] = 1.6; for age 70-79 years, RR = 2.3; for age ≥80 years, RR = 23.1; P = .042), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission comprised pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%). Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at higher risk for readmission and should be counseled and monitored accordingly.

Continue to: Total shoulder arthroplasty...

Total shoulder arthroplasty (TSA) is performed with increasing frequency in the United States and is considered to be cost-effective.^1-4 Following the procedure, patients generally achieve shoulder function and pain relief.^5-8 Despite the success of the procedure, the growing literature on TSA has also reported rates of complications between 3.6% and 25% of the treated patients.^9-16

In recent years, an increasing interest has focused on the rates and risk factors for unplanned hospital readmissions; these variables may not only reflect the quality of patient care but also result in considerable costs to the healthcare system. For instance, among Medicare patients, readmissions within 30 days of discharge occur in almost 20% of cases, costing $17.4 billion per year.¹⁷ Readmission rates increasingly factor into hospital performance metrics and reimbursement, including the Hospital Readmissions Reduction Program of the Patient Protection and Affordable Care Act that reduces Centers for Medicare and Medicaid Services payments to hospitals with high 30-day readmission rates.¹⁸

To date, only a few studies have evaluated readmission following TSA, with 30- to 90-day readmission rates ranging from 4.5% to 7.3%.^19-23 These studies comprised single institution series^20,22 and analyses of administrative databases.^19,21,23 Most studies have shown that readmission occurs more often for medical than surgical reasons, with surgical reasons most commonly including infection and dislocation.^19-23 However, only limited analyses have been conducted regarding risk factors for readmission.^21,23 To date and to our knowledge, no study has investigated reasons for readmission following TSA using nationwide data.

This study aims to determine the rates, risk factors, and reasons for hospital readmission following primary TSA in the United States using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

METHODS

DATA SOURCE

The NSQIP database was utilized to address the study purpose. NSQIP is a nationwide prospective surgical registry established by the American College of Surgeons and reports data from academic and community hospitals across the United States.²⁴ Patients undertaking surgery at these centers are followed by the surgical clinical reviewers at the participating NSQIP sites prospectively for 30 days following the procedure to record complications including readmission. Preoperative and surgical data, such as demographics, medical comorbid diseases, and operative time, are also included. Previous studies have analyzed the complications of various orthopedic surgeries using the NSQIP data.^14,16,25-30

DATA COLLECTION

We retrospectively identified from NSQIP the patients who underwent primary TSA (anatomic or reverse) in 2013 to 2014. The timeframe 2013 to 2014 was used because NSQIP only began recording reasons for readmission in 2013. The inclusion criteria were as follows: Current Procedural Terminology (CPT) code for TSA (23472); preoperative diagnosis according to the International Classification of Diseases, Ninth Revision (ICD-9) codes 714.0, 715.11, 715.31, 715.91, 715.21, 715.89, 716.xx 718.xx, 719.xx, 726.x, 727.xx, and 733.41 (where x is a wild card digit); and no missing demographic, comorbidity, or outcome data. Anatomic and reverse TSA were analyzed together because they share the same CPT code, and the NSQIP database prevents searching by the ICD-9 procedure code.

The rate of unplanned readmission to the hospital within 30 postoperative days was characterized. The reasons for readmission in this 30-day period were only available in 2013 and were determined using the ICD-9 diagnosis codes. Patient demographics were recorded for use in identifying potential risk factors for readmission; the demographic data included sex, age, smoking status, body mass index (BMI), and comorbidities, including end-stage renal disease, dyspnea on exertion, congestive heart failure, diabetes mellitus, hypertension, and chronic obstructive pulmonary disease (COPD).

Continue to: Statistical analysis...

STATISTICAL ANALYSIS

Statistical analyses were performed using Stata version 13.1 (StataCorp). First, using bivariate and multivariate regression, demographic and comorbidity factors were tested for independent association with readmission to the hospital within 30 days of surgery. Second, among the readmitted patients, the reasons for readmission were tabulated. Of note, the reasons for readmission were only documented for the procedures performed in 2013. All tests were 2-tailed and conducted at an α level of 0.05.

RESTULTS

A total of 3627 TSA patients were identified. The mean age (± standard deviation) was 69.4 ± 9.5 years, 55.8% of patients were female, and mean BMI was 30.1 ± 7.0 years. Table 1 provides the additional demographic data. Of the 3627 included patients, 93 (2.56%) were readmitted within 30 days of surgery. The 95% confidence interval for the estimated rate of readmission reached 2.05% to 3.08%.

Table 1. Patient Population

Abbreviation: COPD, chronic obstructive pulmonary disease.

In the bivariate analyses (Table 2), the following factors were positively associated readmission: older age (60-69 years, relative risk [RR] = 1.6; 70-79 years, RR = 2.2; ≥80 years, RR = 3.3; P = .011), dependent functional status (RR = 2.9, P = .008), and anemia (RR = 2.2, P < .001).

Table 2. Bivariate Analysis of Risk Factors for Readmission

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

In the multivariate analyses (Table 3), the following factors were independent risk factors for readmission: older age (60-69 years, RR = 1.6; 70-79 years, RR = 2.3; ≥80 years, RR = 3.1; P =.027), male sex (RR = 1.6, P = .025), anemia (RR = 1.9, P = .005), and dependent functional status (RR = 2.8, P = .012). Interestingly, readmission showed no independent association with diabetes, dyspnea on exertion, BMI, COPD, hypertension, or current smoking status (P > .05 for each).

Table 3. Independent Risk Factors for Readmission on Multivariate Analysis

Abbreviations: CI, confidence interval; COPD, chronic obstructive pulmonary disease; RR, relative risk.

Continue to: Table 4...

The reasons for readmission were available for 84 of the 93 readmitted patients. The most common reasons for readmission included pneumonia (14 cases, 16.7%), dislocation (7 cases, 8.3%), pulmonary embolism (7 cases, 8.3%), and surgical site infection (6 cases, 7.1%) (Table 4).

Table 4. Reasons for Readmission

DISCUSSION

Our analysis of 3042 TSAs from the NSQIP database suggests that unplanned readmission to the hospital occurs following about 1 in 40 cases of TSA. The study also suggests that the most common reasons for readmission encompass pneumonia, dislocation, pulmonary embolism, and surgical site infection. Old age, male sex, anemia, and dependent functional status serve as risk factors for readmission, and patients with such factors should be counseled and monitored accordingly.

In recent years, an increasing emphasis has centered on reducing rates of hospital readmission, with programs such as the Hospital Readmissions Reduction Program of the Affordable Care Act cutting reimbursements for hospitals with high 30-day readmission rates.^17,18 To date, only a few studies have evaluated the reasons for readmission and readmission rates for TSA.^19-23 Initial reports consisted of single-institution TSA registry reviews. For example, Mahoney and colleagues²⁰ retrospectively evaluated shoulder arthroplasty procedures at their institution to document the readmission rates, finding a 5.9% readmission rate at 30 days. Readmission occurred more frequently in the first 30 days following discharge than in the 30- to 90-day period, with the most common reasons for readmission including medical complications, infection, and dislocation. Streubel and colleagues²² evaluated reoperation rates from their institution’s TSA registry, finding a 0.6% reoperation rate for primary TSA at 30 days and 1.5% for revision TSA. Instability and infection were the most common indications for reoperation. Our findings confirm these single-institution results and demonstrate their application to a nationwide sample of TSA, not just to high-volume academic centers. We similarly observed that dislocation, surgical site infection, and medical complications (mostly pneumonia and pulmonary embolism) were common causes of readmission, and that the 30-day readmission rate was about 1 in 40.

Several authors have since used statewide databases to analyze and determine risk factors for readmission following TSA. Lyman and colleagues¹⁹ used the New York State Database to show that higher hospital TSA surgical volume was associated with a lower rate of readmission when age and comorbidities were controlled for in a multivariate model. Old age was also associated with an increased readmission rate in their multivariate analysis, but comorbidities (as measured by the Charlson comorbidity index) presented a nonsignificant associative trend. These authors opted not to determine specific causes of readmission. Schairer and colleagues²¹ used State Inpatient Databases from 7 states, finding a 90-day readmission rate of 7.3%, 82% of which were due to medical complications and 18% of which were due to surgical complications (mostly infection and dislocation). Their multivariate regression revealed that male sex, reverse TSA, Medicaid insurance, patients discharged to inpatient rehabilitation or nursing facilities, medical comorbidities, and low-volume TSA hospitals were associated with readmission. Zhang and colleagues²³ used the same source to show that the 90-day readmission rate reached 14% for surgically treated proximal humerus fractures and higher for patients who underwent open reduction internal fixation, were female, were African American, were discharged to a nursing facility, possessed Medicaid insurance, or experienced medical comorbidities. Most recently, Basques and colleagues³¹ analyzed 1505 TSA cases from 2011 and 2012 in the NSQIP database, finding a 3.3% rate of readmission, with heart disease and hypertension as risk factors for readmission. Although the limitations of the NSQIP database prevented us from analyzing surgeon and hospital TSA volume or reverse vs anatomic TSA, our results confirm that the findings from statewide database studies apply to the United States nationwide NSQIP database. Old patient age, male sex, and medical comorbidities (anemia and dependent functional status) are independent risk factors for TSA readmission. We identified pneumonia, dislocation, pulmonary embolism, and surgical site infection as the most common reasons for readmission.

This study features several limitations that should be considered when interpreting the results. Anatomic and reverse TSA share a CPT code and were not separated using NSQIP data. A number of studies have reported that reverse TSA may place patients at higher risk for readmission;^20,21 however, confounding by other patient factors could play a role in this finding. The 30-day timeframe for readmission is another potential limitation; however, this timeframe is frequently used in other studies and is the relevant timeframe for the reduced reimbursement penalties from the Hospital Readmissions Reduction Program of the Affordable Care Act.¹⁸ Furthermore, the NSQIP database contains no information on surgeon or hospital TSA volume, which is a result of safeguards for patient and provider privacy. Additionally, readmission data were only available for 2011 to 2013, with causes of readmission only present in 2013. Although provided with such current information, we cannot analyze readmission trends over time, such as in response to the Affordable Care Act of 2010. Finally, although NSQIP surgical clinical reviewers strive to identify readmissions to other hospitals during their reviews of outpatient medical records, proportions of these readmissions are possibly missed. Therefore, our 30-day readmission rate may slightly underestimate the true rate.

Despite these limitations, the NSQIP database offers a unique opportunity to examine risk factors and reasons for readmission following TSA. The prior literature on readmission following TSA stemmed either from limited samples or administrative data, which feature known limitations.³² By utilizing a large, prospective, non-administrative, nationwide sample, our findings are probably both more reliable and generalizable to the country as a whole.

CONCLUSION

Unplanned readmission occurs following about 1 in 40 cases of TSA. The most common causes of readmission include pneumonia, dislocation, pulmonary embolism, and surgical site infection. Patients with old age, male sex, anemia, and dependent functional status are at a higher risk for readmission and should be counseled and monitored accordingly.

This paper will be judged for the Resident Writer’s Award.

ANSWER

The radiograph shows rib fractures on the left side (arrows); on the same side, there is a moderate-sized pleural effusion—presumably a hemothorax from the trauma.

A closer look at the mid-thoracic spine reveals some irregularity and possible deformity—note the slight offset. This finding is strongly suspicious for a fracture.

A subsequent CT revealed a thoracic burst fracture with retropulsion into the spinal canal.

ANSWER

The radiograph shows rib fractures on the left side (arrows); on the same side, there is a moderate-sized pleural effusion—presumably a hemothorax from the trauma.

A closer look at the mid-thoracic spine reveals some irregularity and possible deformity—note the slight offset. This finding is strongly suspicious for a fracture.

A subsequent CT revealed a thoracic burst fracture with retropulsion into the spinal canal.

ANSWER

The radiograph shows rib fractures on the left side (arrows); on the same side, there is a moderate-sized pleural effusion—presumably a hemothorax from the trauma.

A closer look at the mid-thoracic spine reveals some irregularity and possible deformity—note the slight offset. This finding is strongly suspicious for a fracture.

A subsequent CT revealed a thoracic burst fracture with retropulsion into the spinal canal.

ABSTRACT

Current literature regarding complications following total joint arthroplasty have primarily focused on patients with osteoarthritis (OA), with less emphasis on the trends and in-hospital outcomes of rheumatoid arthritis (RA) patients undergoing these procedures. The purpose of this study is to analyze the outcomes and trends of RA patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA) compared to OA patients.

Data from the Nationwide Inpatient Sample from 2006 to 2011 was extracted using the International Classification of Diseases, Ninth Revision codes for patients that received a TKA or THA. Outcome measures included cardiovascular complications, cerebrovascular complications, pulmonary complications, wound dehiscence, and infection. Inpatient and hospital demographics including primary diagnosis, age, gender, primary payer, hospital teaching status, Charlson Comorbidity Index score, hospital bed size, location, and median household income were analyzed.

Logistic regression analysis of OA vs RA patients with patient outcomes revealed that osteoarthritic THA candidates had lower risk for cardiovascular complications, pulmonary complications, wound dehiscence, infections, and systemic complications, compared to rheumatoid patients. There was a significantly elevated risk of cerebrovascular complication in osteoarthritic THA compared to RA THA. OA patients undergoing TKA had significantly higher risk for cardiovascular and cerebrovascular complications. There were significant decreases in mechanical wounds, infection, and systemic complications in the OA TKA patients.

RA patients are at higher risk for postoperative infection, wound dehiscence, and systemic complications after TKA and THA compared to OA patients. These findings highlight the importance of preoperative medical clearance and management to optimize RA patients and improve the postoperative outcomes.

Continue to: RA is a chronic systemic inflammatory disease...

Rheumatoid arthritis (RA) is a chronic systemic inflammatory disease that causes joint deterioration, leading to pain, disability, systemic complications, short lifespan, and decline in quality of life.^1-3 The deterioration primarily affects the synovial membranes of joints, causing arthritis and resulting in extra-articular sequelae such as cardiovascular disease,⁴ pulmonary disease,⁵ and increased infection rates.^3,6 RA is the most prevalent inflammatory arthritis worldwide and affects up to 50 cases per 100,000 in both the US and northern Europe.^2,7-9 Although the gold standard of care for these patients is medical management with immunosuppressant drugs such as disease-modifying anti-rheumatic drugs (DMARDs), total joint arthroplasty (TJA) remains an important tool in the management of joint deterioration in such patients.

Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common procedures utilized to treat disorders that cause joint pain and hindered joint mobility, including osteoarthritis (OA) and RA. Given the aging population, the amount of TKAs and THAs performed in the US has consistently increased each year, with the vast majority of this increase composed of patients with OA.¹⁰ As a result, previous studies investigated the trends and outcomes of these procedures in patients with OA, but relatively less is known about the outcomes and trends of patients with RA undergoing the same surgeries.

Given that RA is a fundamentally different condition with its own pathological characteristics, an understanding of how these differences may impact postoperative outcomes in patients with RA is important. This study aims to present a comparative analysis of the trends and postoperative outcomes between patients with RA and OA undergoing TKA and THA (Figure 1, Tables 1 and 2).

Table 1. Demographics of Total Knee Arthroplasty Patients Based on Primary Diagnosis of Osteoarthritis