Alan M. Hirahara, MD, FRCS(C)

Take-Home Points

• The SCR is a viable treatment option for massive, irreparable RCTs.
• Arm position and exact measurement between anchors will help ensure proper graft tensioning.
• Anterior and posterior tension and margin convergence are critical to stabilizing the graft.
• Acromial-humeral distance, ASES, and VAS scores are improved and maintained over long-term follow-up.
• The dermal allograft should be 3.0 mm or thicker.

Conventional treatments for irreparable massive rotator cuff tears (RCTs) have ranged from nonoperative care to débridement and biceps tenotomy,^1,2 partial cuff repair,^3,4 bridging patch grafts,⁵ tendon transfers,^6,7 and reverse total shoulder arthroplasty (RTSA).^8,9 Superior capsular reconstruction (SCR), originally described by Mihata and colleagues,¹⁰ has been developed as an alternative to these interventions. Dr. Hirahara modified the technique to use dermal allograft instead of fascia lata autograft.^10,11

Biomechanical analysis has confirmed the integral role of the superior capsule in shoulder function.^10,12-14 In the presence of a massive RCT, the humeral head migrates superiorly, causing significant pain and functional deficits, such as pseudoparalysis. It is theorized that reestablishing this important stabilizer—centering the humeral head in the glenoid and allowing the larger muscles to move the arm about a proper fulcrum—improves function and decreases pain.

Using ultrasonography (US), radiography, magnetic resonance imaging (MRI), clinical outcome scores, and a visual analog scale (VAS) for pain, we prospectively evaluated minimum 2-year clinical outcomes of performing SCR with dermal allograft for irreparable RCTs.

Methods

Except where noted otherwise, all products mentioned in this section were made by Arthrex.

Surgical Technique

The surgical technique used here was described by Hirahara and Adams.¹¹ ArthroFlex dermal allograft was attached to the greater tuberosity and the glenoid, creating a superior restraint that replaced the anatomical superior capsule (Figures 1A, 1B). Some cases included biceps tenotomy, subscapularis repair, or infraspinatus repair.

Medial fixation was obtained with a PASTA (partial articular supraspinatus tendon avulsion) bridge-type construct¹⁵ that consisted of two 3.0-mm BioComposite SutureTak anchors (placed medially on the glenoid rim, medial to the labrum) and a 3.5-mm BioComposite Vented SwiveLock. In some cases, a significant amount of tissue was present medially, and the third anchor was not used; instead, a double surgeon knot was used to fixate the double pulley medially.

Posterior margin convergence (PMC) was performed in all cases. Anterior margin convergence (AMC) was performed in only 3 cases.

Clinical Evaluation

All patients who underwent SCR were followed prospectively, and all signed an informed consent form. Between 2014 and the time of this study, 9 patients had surgery with a minimum 2-year follow-up. Before surgery, all patients received a diagnosis of full-thickness RCT with decreased acromial-humeral distance (AHD). One patient had RTSA 18 months after surgery, did not reach the 2-year follow-up, and was excluded from the data analysis. Patients were clinically evaluated on the 100-point American Shoulder and Elbow Surgeons (ASES) shoulder index and on a 10-point VAS for pain—before surgery, monthly for the first 6 months after surgery, then every 6 months until 2 years after surgery, and yearly thereafter. These patients were compared with Dr. Hirahara’s historical control patients, who had undergone repair of massive RCTs. Mean graft size was calculated and reported. Cases were separated and analyzed on the basis of whether AMC was performed. Student t tests were used to determine statistical differences between study patients’ preoperative and postoperative scores, between study and historical control patients, and between patients who had AMC performed and those who did not (P < .05).

Imaging

For all SCR patients, preoperative and postoperative radiographs were obtained in 2 planes: anterior-posterior with arm in neutral rotation, and scapular Y. On anteroposterior radiographs, AHD was measured from the most proximal aspect of the humeral head in a vertical line to the most inferior portion of the acromion (Figures 2A, 2B).

Results

The Table provides an overview of the study results. Eight patients (6 men, 2 women) met the final inclusion criteria for postoperative ASES and VAS data analysis.

AHD was measured on a standard anteroposterior radiograph in neutral rotation. The Hamada grading scale16 was used to classify the massive RCTs before and after surgery. Before surgery, 4 were grade 4A, 1 grade 3, 2 grade 2, and 1 grade 1; immediately after surgery, all were grade 1 (AHD, ≥6 mm). Two years after surgery, 1 patient had an AHD of 4.6 mm after a failure caused by a fall. Mean (SD) preoperative AHD was 4.50 (2.25) mm (range, 1.7-7.9 mm). Radiographs obtained immediately (mean, 1.22 months; range, 1 day-2.73 months) after surgery showed AHD was significantly (P < .0008) increased (mean, 8.48 mm; SD, 1.25 mm; range, 6.0-10.0 mm) (Figure 5).

Mean graft size was 2.9 mm medial × 3.6 mm lateral × 5.4 mm anterior × 5.4 mm posterior. Three patients had AMC performed. There was a significant (P < .05) difference in ASES scores between patients who had AMC performed (93) and those who did not (77).

Ultrasonography

Two weeks to 2 months after surgery, all patients had an intact capsular graft and no pulsatile vessels on US. Between 4 months and 10 months, US showed the construct intact laterally in all cases, a pulsatile vessel in the graft at the tuberosity (evidence of blood flow) in 4 of 5 cases, and a pulsatile vessel hypertrophied in 2 cases (Figures 6A, 6B).

Magnetic Resonance Imaging

Before surgery, 4 patients had Goutallier¹⁷ stage 4 rotator cuff muscle degeneration, 2 had stage 3 degeneration, and 2 had stage 2 degeneration. Throughout the follow-up period, US was as effective as MRI in determining graft integrity, graft thickness, and greater tuberosity fixation. Therefore, the SCRs were assessed primarily with US. MRI was ordered only if a failure was suspected or if the patient had some form of trauma. A total of 7 MRIs were ordered for 5 of the 8 patients in the study. The graft was intact in 4 of the 5 (Figures 7A-7C) and ruptured in the fifth.

Discussion

Mihata and colleagues¹⁰ published 2-year data for their reconstructive procedure with fascia lata autograft. In a modification of their procedure, Dr. Hirahara used dermal allograft to recreate the superior capsule.¹¹ The results of the present 2-year study mirror the clinical outcomes reported by Mihata and colleagues¹⁰ and confirm that SCR improves functional outcomes and increases AHD regardless of graft type used.

The outcomes of the SCR patients in our study were significantly better than the outcomes of the historical control patients, who underwent repair of massive RCTs. Although there was no significant difference in the 2 groups’ ASES scores, the control patients had significantly higher postoperative VAS pain scores. We think that, as more patients undergo SCR and the population sample increases, we will see a significant difference in ASES scores as well (our SCR patients already showed a trend toward improved ASES scores).

Compared with RTSA, SCR has fewer risks and fewer complications and does not limit further surgical options.^8,9,18 The 9 patients who had surgery with a minimum 2-year follow-up in our study had 4 complications. Six months after surgery, 1 patient fell and tore the infraspinatus and subscapularis muscles. Outcomes continued to improve, and no issues were reported, despite a decrease in AHD, from 8 mm immediately after surgery to 4.6 mm 2 years after surgery.

Two patients were in motor vehicle accidents. In 1 case, the accident occurred about 2 months after surgery. This patient also sustained a possible injury in a fall after receiving general anesthesia for a dental procedure. After having done very well the preceding months, the patient now reported increasing pain and dysfunction. MRI showed loss of glenoid fixation. Improved ASES and VAS pain scores were maintained throughout the follow-up period. AHD was increased at 13 months and mildly decreased at 2 years. Glenoid fixation was obtained with 2 anchors and a double surgeon knot. When possible, however, it is best to add an anchor and double-row fixation, as 3 anchors and a double-row construct are biomechanically stronger.^19-24

The other motor vehicle accident occurred about 23 months after surgery. Two months later, a graft rupture was found on US and MRI, but the patient was maintaining full range of motion, AHD, and improved strength. The 1.5-mm graft in this patient was thinner than the 3.5-mm grafts in the rest of the study group. This was the only patient who developed a graft rupture rather than loss of fixation.

If only patients with graft thickness >3.0 mm are included in the data analysis, mean ASES score rises to 89.76, and mean VAS pain score drops to 0. Therefore, we argue against using a graft thinner than 3.5 mm. Our excellent study results indicate that larger grafts are unnecessary. Mihata and colleagues¹⁰ used fascia lata grafts of 6 mm to 8 mm. Ultimate load to failure is significantly higher for dermal allograft than for fascia lata graft.²⁵ In SCR, the stronger dermal allograft withstands applied forces and repeated deformations and has excellent clinical outcomes.

Only 1 patient had a failure that required RTSA. VAS pain scores were lower and ASES scores were improved the first year after surgery, but then function deteriorated. The patient said there was no specific precipitating incident. Computed tomography arthrogram, ordered to assess the construct, showed anterior and superior subluxation of the humeral head, even with an intact subscapularis tendon—an indication of underlying instability, which most likely caused the failure. Eighteen months after surgery, the patient was able to undergo RTSA. On further evaluation of this patient’s procedure, it was determined that the graft needed better fixation anteriorly.

Mihata and colleagues^10,12,14 indicated that AMC was unnecessary, and our procedure did not require it. However, data in our prospective evaluation began showing improved outcomes with AMC. As dermal allograft is more elastic than fascia lata autograft,²⁵ we concluded that graft tensioning is key to the success of this procedure. Graft tension depends on many factors, including exact measurement of the distances between the anchors to punch holes in the graft, arm position to set the relationship between the anchor distances, and AMC and PMC. We recommend placing the arm in neutral rotation, neutral flexion, and abduction with the patient at rest, based on the size of the patient’s latissimus dorsi. Too much abduction causes overtensioning, and excess rotation or flexion-extension changes the distance between the glenoid and the greater tuberosity asymmetrically, from anterior to posterior. With the arm in neutral position, distances between anchors are accurately measured, and these measurements are used to determine graft size.

Graft tension is also needed to control the amount of elasticity allowed by the graft and thereby maintain stability, as shown by the Poisson ratio, the ratio of transverse contraction to longitudinal extension on a material in the presence of a stretching force. As applied to SCR, it is the ratio of mediolateral elasticity to anteroposterior deformation or constraint. If the graft is appropriately secured in the anteroposterior direction by way of ACM and PMC, elongation in the medial-lateral direction will be limited—reducing the elasticity of the graft, improving overall stability, and ultimately producing better clinical outcomes. This issue was discussed by Burkhart and colleagues²⁶ with respect to the “rotator cable complex,” which now might be best described as the “rotator-capsule cable complex.” In our study, this phenomenon was evident in the finding that patients who had AMC performed did significantly better than patients who did not have AMC performed. The ability of dermal allograft to deform in these dimensions without failure while allowing excellent range of motion makes dermal allograft an exceptional choice for grafting during SCR. Mihata25 also found dermal allograft had a clear advantage in providing better range of motion, whereas fascia lata autograft resulted in a stiffer construct. 

Dermal allograft can also incorporate into the body and transform into host tissue. The literature has described musculoskeletal US as an effective diagnostic and interventional tool.^27-31 We used it to evaluate graft size, patency, and viability. As can be seen on US, the native rotator cuff does not have any pulsatile vessels and is fed by capillary flow. Dermal allograft has native vasculature built into the tissue. After 4 months to 8 months, presence of pulsatile vessels within the graft at the greater tuberosity indicates clear revascularization and incorporation of the tissue (Figure 6B). Disappearance of pulsatile vessels on US after 1 year indicates transformation to a stabilizing structure analogous to capsule or ligament with capillary flow. US also showed graft hypertrophy after 2 years, supporting a finding of integration and growth.

Conclusion

In the past, patients with irreparable massive RCTs had few good surgical management options, RTSA being the most definitive. SCR is technically challenging and requires use of specific implantation methods but can provide patients with outstanding relief. Our clinical data showed that technically well executed SCR effectively restores the superior restraints in the glenohumeral joint and thereby increases function and decreases pain in patients with irreparable massive RCTs, even after 2 years.

Take-Home Points

• The SCR is a viable treatment option for massive, irreparable RCTs.
• Arm position and exact measurement between anchors will help ensure proper graft tensioning.
• Anterior and posterior tension and margin convergence are critical to stabilizing the graft.
• Acromial-humeral distance, ASES, and VAS scores are improved and maintained over long-term follow-up.
• The dermal allograft should be 3.0 mm or thicker.

Conventional treatments for irreparable massive rotator cuff tears (RCTs) have ranged from nonoperative care to débridement and biceps tenotomy,^1,2 partial cuff repair,^3,4 bridging patch grafts,⁵ tendon transfers,^6,7 and reverse total shoulder arthroplasty (RTSA).^8,9 Superior capsular reconstruction (SCR), originally described by Mihata and colleagues,¹⁰ has been developed as an alternative to these interventions. Dr. Hirahara modified the technique to use dermal allograft instead of fascia lata autograft.^10,11

Biomechanical analysis has confirmed the integral role of the superior capsule in shoulder function.^10,12-14 In the presence of a massive RCT, the humeral head migrates superiorly, causing significant pain and functional deficits, such as pseudoparalysis. It is theorized that reestablishing this important stabilizer—centering the humeral head in the glenoid and allowing the larger muscles to move the arm about a proper fulcrum—improves function and decreases pain.

Using ultrasonography (US), radiography, magnetic resonance imaging (MRI), clinical outcome scores, and a visual analog scale (VAS) for pain, we prospectively evaluated minimum 2-year clinical outcomes of performing SCR with dermal allograft for irreparable RCTs.

Methods

Except where noted otherwise, all products mentioned in this section were made by Arthrex.

Surgical Technique

The surgical technique used here was described by Hirahara and Adams.¹¹ ArthroFlex dermal allograft was attached to the greater tuberosity and the glenoid, creating a superior restraint that replaced the anatomical superior capsule (Figures 1A, 1B). Some cases included biceps tenotomy, subscapularis repair, or infraspinatus repair.

Medial fixation was obtained with a PASTA (partial articular supraspinatus tendon avulsion) bridge-type construct¹⁵ that consisted of two 3.0-mm BioComposite SutureTak anchors (placed medially on the glenoid rim, medial to the labrum) and a 3.5-mm BioComposite Vented SwiveLock. In some cases, a significant amount of tissue was present medially, and the third anchor was not used; instead, a double surgeon knot was used to fixate the double pulley medially.

Posterior margin convergence (PMC) was performed in all cases. Anterior margin convergence (AMC) was performed in only 3 cases.

Clinical Evaluation

All patients who underwent SCR were followed prospectively, and all signed an informed consent form. Between 2014 and the time of this study, 9 patients had surgery with a minimum 2-year follow-up. Before surgery, all patients received a diagnosis of full-thickness RCT with decreased acromial-humeral distance (AHD). One patient had RTSA 18 months after surgery, did not reach the 2-year follow-up, and was excluded from the data analysis. Patients were clinically evaluated on the 100-point American Shoulder and Elbow Surgeons (ASES) shoulder index and on a 10-point VAS for pain—before surgery, monthly for the first 6 months after surgery, then every 6 months until 2 years after surgery, and yearly thereafter. These patients were compared with Dr. Hirahara’s historical control patients, who had undergone repair of massive RCTs. Mean graft size was calculated and reported. Cases were separated and analyzed on the basis of whether AMC was performed. Student t tests were used to determine statistical differences between study patients’ preoperative and postoperative scores, between study and historical control patients, and between patients who had AMC performed and those who did not (P < .05).

Imaging

For all SCR patients, preoperative and postoperative radiographs were obtained in 2 planes: anterior-posterior with arm in neutral rotation, and scapular Y. On anteroposterior radiographs, AHD was measured from the most proximal aspect of the humeral head in a vertical line to the most inferior portion of the acromion (Figures 2A, 2B).

Results

The Table provides an overview of the study results. Eight patients (6 men, 2 women) met the final inclusion criteria for postoperative ASES and VAS data analysis.

AHD was measured on a standard anteroposterior radiograph in neutral rotation. The Hamada grading scale16 was used to classify the massive RCTs before and after surgery. Before surgery, 4 were grade 4A, 1 grade 3, 2 grade 2, and 1 grade 1; immediately after surgery, all were grade 1 (AHD, ≥6 mm). Two years after surgery, 1 patient had an AHD of 4.6 mm after a failure caused by a fall. Mean (SD) preoperative AHD was 4.50 (2.25) mm (range, 1.7-7.9 mm). Radiographs obtained immediately (mean, 1.22 months; range, 1 day-2.73 months) after surgery showed AHD was significantly (P < .0008) increased (mean, 8.48 mm; SD, 1.25 mm; range, 6.0-10.0 mm) (Figure 5).

Mean graft size was 2.9 mm medial × 3.6 mm lateral × 5.4 mm anterior × 5.4 mm posterior. Three patients had AMC performed. There was a significant (P < .05) difference in ASES scores between patients who had AMC performed (93) and those who did not (77).

Ultrasonography

Two weeks to 2 months after surgery, all patients had an intact capsular graft and no pulsatile vessels on US. Between 4 months and 10 months, US showed the construct intact laterally in all cases, a pulsatile vessel in the graft at the tuberosity (evidence of blood flow) in 4 of 5 cases, and a pulsatile vessel hypertrophied in 2 cases (Figures 6A, 6B).

Magnetic Resonance Imaging

Before surgery, 4 patients had Goutallier¹⁷ stage 4 rotator cuff muscle degeneration, 2 had stage 3 degeneration, and 2 had stage 2 degeneration. Throughout the follow-up period, US was as effective as MRI in determining graft integrity, graft thickness, and greater tuberosity fixation. Therefore, the SCRs were assessed primarily with US. MRI was ordered only if a failure was suspected or if the patient had some form of trauma. A total of 7 MRIs were ordered for 5 of the 8 patients in the study. The graft was intact in 4 of the 5 (Figures 7A-7C) and ruptured in the fifth.

Discussion

Mihata and colleagues¹⁰ published 2-year data for their reconstructive procedure with fascia lata autograft. In a modification of their procedure, Dr. Hirahara used dermal allograft to recreate the superior capsule.¹¹ The results of the present 2-year study mirror the clinical outcomes reported by Mihata and colleagues¹⁰ and confirm that SCR improves functional outcomes and increases AHD regardless of graft type used.

The outcomes of the SCR patients in our study were significantly better than the outcomes of the historical control patients, who underwent repair of massive RCTs. Although there was no significant difference in the 2 groups’ ASES scores, the control patients had significantly higher postoperative VAS pain scores. We think that, as more patients undergo SCR and the population sample increases, we will see a significant difference in ASES scores as well (our SCR patients already showed a trend toward improved ASES scores).

Compared with RTSA, SCR has fewer risks and fewer complications and does not limit further surgical options.^8,9,18 The 9 patients who had surgery with a minimum 2-year follow-up in our study had 4 complications. Six months after surgery, 1 patient fell and tore the infraspinatus and subscapularis muscles. Outcomes continued to improve, and no issues were reported, despite a decrease in AHD, from 8 mm immediately after surgery to 4.6 mm 2 years after surgery.

Two patients were in motor vehicle accidents. In 1 case, the accident occurred about 2 months after surgery. This patient also sustained a possible injury in a fall after receiving general anesthesia for a dental procedure. After having done very well the preceding months, the patient now reported increasing pain and dysfunction. MRI showed loss of glenoid fixation. Improved ASES and VAS pain scores were maintained throughout the follow-up period. AHD was increased at 13 months and mildly decreased at 2 years. Glenoid fixation was obtained with 2 anchors and a double surgeon knot. When possible, however, it is best to add an anchor and double-row fixation, as 3 anchors and a double-row construct are biomechanically stronger.^19-24

The other motor vehicle accident occurred about 23 months after surgery. Two months later, a graft rupture was found on US and MRI, but the patient was maintaining full range of motion, AHD, and improved strength. The 1.5-mm graft in this patient was thinner than the 3.5-mm grafts in the rest of the study group. This was the only patient who developed a graft rupture rather than loss of fixation.

If only patients with graft thickness >3.0 mm are included in the data analysis, mean ASES score rises to 89.76, and mean VAS pain score drops to 0. Therefore, we argue against using a graft thinner than 3.5 mm. Our excellent study results indicate that larger grafts are unnecessary. Mihata and colleagues¹⁰ used fascia lata grafts of 6 mm to 8 mm. Ultimate load to failure is significantly higher for dermal allograft than for fascia lata graft.²⁵ In SCR, the stronger dermal allograft withstands applied forces and repeated deformations and has excellent clinical outcomes.

Only 1 patient had a failure that required RTSA. VAS pain scores were lower and ASES scores were improved the first year after surgery, but then function deteriorated. The patient said there was no specific precipitating incident. Computed tomography arthrogram, ordered to assess the construct, showed anterior and superior subluxation of the humeral head, even with an intact subscapularis tendon—an indication of underlying instability, which most likely caused the failure. Eighteen months after surgery, the patient was able to undergo RTSA. On further evaluation of this patient’s procedure, it was determined that the graft needed better fixation anteriorly.

Mihata and colleagues^10,12,14 indicated that AMC was unnecessary, and our procedure did not require it. However, data in our prospective evaluation began showing improved outcomes with AMC. As dermal allograft is more elastic than fascia lata autograft,²⁵ we concluded that graft tensioning is key to the success of this procedure. Graft tension depends on many factors, including exact measurement of the distances between the anchors to punch holes in the graft, arm position to set the relationship between the anchor distances, and AMC and PMC. We recommend placing the arm in neutral rotation, neutral flexion, and abduction with the patient at rest, based on the size of the patient’s latissimus dorsi. Too much abduction causes overtensioning, and excess rotation or flexion-extension changes the distance between the glenoid and the greater tuberosity asymmetrically, from anterior to posterior. With the arm in neutral position, distances between anchors are accurately measured, and these measurements are used to determine graft size.

Graft tension is also needed to control the amount of elasticity allowed by the graft and thereby maintain stability, as shown by the Poisson ratio, the ratio of transverse contraction to longitudinal extension on a material in the presence of a stretching force. As applied to SCR, it is the ratio of mediolateral elasticity to anteroposterior deformation or constraint. If the graft is appropriately secured in the anteroposterior direction by way of ACM and PMC, elongation in the medial-lateral direction will be limited—reducing the elasticity of the graft, improving overall stability, and ultimately producing better clinical outcomes. This issue was discussed by Burkhart and colleagues²⁶ with respect to the “rotator cable complex,” which now might be best described as the “rotator-capsule cable complex.” In our study, this phenomenon was evident in the finding that patients who had AMC performed did significantly better than patients who did not have AMC performed. The ability of dermal allograft to deform in these dimensions without failure while allowing excellent range of motion makes dermal allograft an exceptional choice for grafting during SCR. Mihata25 also found dermal allograft had a clear advantage in providing better range of motion, whereas fascia lata autograft resulted in a stiffer construct. 

Dermal allograft can also incorporate into the body and transform into host tissue. The literature has described musculoskeletal US as an effective diagnostic and interventional tool.^27-31 We used it to evaluate graft size, patency, and viability. As can be seen on US, the native rotator cuff does not have any pulsatile vessels and is fed by capillary flow. Dermal allograft has native vasculature built into the tissue. After 4 months to 8 months, presence of pulsatile vessels within the graft at the greater tuberosity indicates clear revascularization and incorporation of the tissue (Figure 6B). Disappearance of pulsatile vessels on US after 1 year indicates transformation to a stabilizing structure analogous to capsule or ligament with capillary flow. US also showed graft hypertrophy after 2 years, supporting a finding of integration and growth.

Conclusion

In the past, patients with irreparable massive RCTs had few good surgical management options, RTSA being the most definitive. SCR is technically challenging and requires use of specific implantation methods but can provide patients with outstanding relief. Our clinical data showed that technically well executed SCR effectively restores the superior restraints in the glenohumeral joint and thereby increases function and decreases pain in patients with irreparable massive RCTs, even after 2 years.

Take-Home Points

• The SCR is a viable treatment option for massive, irreparable RCTs.
• Arm position and exact measurement between anchors will help ensure proper graft tensioning.
• Anterior and posterior tension and margin convergence are critical to stabilizing the graft.
• Acromial-humeral distance, ASES, and VAS scores are improved and maintained over long-term follow-up.
• The dermal allograft should be 3.0 mm or thicker.

Conventional treatments for irreparable massive rotator cuff tears (RCTs) have ranged from nonoperative care to débridement and biceps tenotomy,^1,2 partial cuff repair,^3,4 bridging patch grafts,⁵ tendon transfers,^6,7 and reverse total shoulder arthroplasty (RTSA).^8,9 Superior capsular reconstruction (SCR), originally described by Mihata and colleagues,¹⁰ has been developed as an alternative to these interventions. Dr. Hirahara modified the technique to use dermal allograft instead of fascia lata autograft.^10,11

Biomechanical analysis has confirmed the integral role of the superior capsule in shoulder function.^10,12-14 In the presence of a massive RCT, the humeral head migrates superiorly, causing significant pain and functional deficits, such as pseudoparalysis. It is theorized that reestablishing this important stabilizer—centering the humeral head in the glenoid and allowing the larger muscles to move the arm about a proper fulcrum—improves function and decreases pain.

Using ultrasonography (US), radiography, magnetic resonance imaging (MRI), clinical outcome scores, and a visual analog scale (VAS) for pain, we prospectively evaluated minimum 2-year clinical outcomes of performing SCR with dermal allograft for irreparable RCTs.

Methods

Except where noted otherwise, all products mentioned in this section were made by Arthrex.

Surgical Technique

The surgical technique used here was described by Hirahara and Adams.¹¹ ArthroFlex dermal allograft was attached to the greater tuberosity and the glenoid, creating a superior restraint that replaced the anatomical superior capsule (Figures 1A, 1B). Some cases included biceps tenotomy, subscapularis repair, or infraspinatus repair.

Medial fixation was obtained with a PASTA (partial articular supraspinatus tendon avulsion) bridge-type construct¹⁵ that consisted of two 3.0-mm BioComposite SutureTak anchors (placed medially on the glenoid rim, medial to the labrum) and a 3.5-mm BioComposite Vented SwiveLock. In some cases, a significant amount of tissue was present medially, and the third anchor was not used; instead, a double surgeon knot was used to fixate the double pulley medially.

Posterior margin convergence (PMC) was performed in all cases. Anterior margin convergence (AMC) was performed in only 3 cases.

Clinical Evaluation

All patients who underwent SCR were followed prospectively, and all signed an informed consent form. Between 2014 and the time of this study, 9 patients had surgery with a minimum 2-year follow-up. Before surgery, all patients received a diagnosis of full-thickness RCT with decreased acromial-humeral distance (AHD). One patient had RTSA 18 months after surgery, did not reach the 2-year follow-up, and was excluded from the data analysis. Patients were clinically evaluated on the 100-point American Shoulder and Elbow Surgeons (ASES) shoulder index and on a 10-point VAS for pain—before surgery, monthly for the first 6 months after surgery, then every 6 months until 2 years after surgery, and yearly thereafter. These patients were compared with Dr. Hirahara’s historical control patients, who had undergone repair of massive RCTs. Mean graft size was calculated and reported. Cases were separated and analyzed on the basis of whether AMC was performed. Student t tests were used to determine statistical differences between study patients’ preoperative and postoperative scores, between study and historical control patients, and between patients who had AMC performed and those who did not (P < .05).

Imaging

For all SCR patients, preoperative and postoperative radiographs were obtained in 2 planes: anterior-posterior with arm in neutral rotation, and scapular Y. On anteroposterior radiographs, AHD was measured from the most proximal aspect of the humeral head in a vertical line to the most inferior portion of the acromion (Figures 2A, 2B).

Results

The Table provides an overview of the study results. Eight patients (6 men, 2 women) met the final inclusion criteria for postoperative ASES and VAS data analysis.

AHD was measured on a standard anteroposterior radiograph in neutral rotation. The Hamada grading scale16 was used to classify the massive RCTs before and after surgery. Before surgery, 4 were grade 4A, 1 grade 3, 2 grade 2, and 1 grade 1; immediately after surgery, all were grade 1 (AHD, ≥6 mm). Two years after surgery, 1 patient had an AHD of 4.6 mm after a failure caused by a fall. Mean (SD) preoperative AHD was 4.50 (2.25) mm (range, 1.7-7.9 mm). Radiographs obtained immediately (mean, 1.22 months; range, 1 day-2.73 months) after surgery showed AHD was significantly (P < .0008) increased (mean, 8.48 mm; SD, 1.25 mm; range, 6.0-10.0 mm) (Figure 5).

Mean graft size was 2.9 mm medial × 3.6 mm lateral × 5.4 mm anterior × 5.4 mm posterior. Three patients had AMC performed. There was a significant (P < .05) difference in ASES scores between patients who had AMC performed (93) and those who did not (77).

Ultrasonography

Two weeks to 2 months after surgery, all patients had an intact capsular graft and no pulsatile vessels on US. Between 4 months and 10 months, US showed the construct intact laterally in all cases, a pulsatile vessel in the graft at the tuberosity (evidence of blood flow) in 4 of 5 cases, and a pulsatile vessel hypertrophied in 2 cases (Figures 6A, 6B).

Magnetic Resonance Imaging

Before surgery, 4 patients had Goutallier¹⁷ stage 4 rotator cuff muscle degeneration, 2 had stage 3 degeneration, and 2 had stage 2 degeneration. Throughout the follow-up period, US was as effective as MRI in determining graft integrity, graft thickness, and greater tuberosity fixation. Therefore, the SCRs were assessed primarily with US. MRI was ordered only if a failure was suspected or if the patient had some form of trauma. A total of 7 MRIs were ordered for 5 of the 8 patients in the study. The graft was intact in 4 of the 5 (Figures 7A-7C) and ruptured in the fifth.

Discussion

Mihata and colleagues¹⁰ published 2-year data for their reconstructive procedure with fascia lata autograft. In a modification of their procedure, Dr. Hirahara used dermal allograft to recreate the superior capsule.¹¹ The results of the present 2-year study mirror the clinical outcomes reported by Mihata and colleagues¹⁰ and confirm that SCR improves functional outcomes and increases AHD regardless of graft type used.

The outcomes of the SCR patients in our study were significantly better than the outcomes of the historical control patients, who underwent repair of massive RCTs. Although there was no significant difference in the 2 groups’ ASES scores, the control patients had significantly higher postoperative VAS pain scores. We think that, as more patients undergo SCR and the population sample increases, we will see a significant difference in ASES scores as well (our SCR patients already showed a trend toward improved ASES scores).

Compared with RTSA, SCR has fewer risks and fewer complications and does not limit further surgical options.^8,9,18 The 9 patients who had surgery with a minimum 2-year follow-up in our study had 4 complications. Six months after surgery, 1 patient fell and tore the infraspinatus and subscapularis muscles. Outcomes continued to improve, and no issues were reported, despite a decrease in AHD, from 8 mm immediately after surgery to 4.6 mm 2 years after surgery.

Two patients were in motor vehicle accidents. In 1 case, the accident occurred about 2 months after surgery. This patient also sustained a possible injury in a fall after receiving general anesthesia for a dental procedure. After having done very well the preceding months, the patient now reported increasing pain and dysfunction. MRI showed loss of glenoid fixation. Improved ASES and VAS pain scores were maintained throughout the follow-up period. AHD was increased at 13 months and mildly decreased at 2 years. Glenoid fixation was obtained with 2 anchors and a double surgeon knot. When possible, however, it is best to add an anchor and double-row fixation, as 3 anchors and a double-row construct are biomechanically stronger.^19-24

The other motor vehicle accident occurred about 23 months after surgery. Two months later, a graft rupture was found on US and MRI, but the patient was maintaining full range of motion, AHD, and improved strength. The 1.5-mm graft in this patient was thinner than the 3.5-mm grafts in the rest of the study group. This was the only patient who developed a graft rupture rather than loss of fixation.

If only patients with graft thickness >3.0 mm are included in the data analysis, mean ASES score rises to 89.76, and mean VAS pain score drops to 0. Therefore, we argue against using a graft thinner than 3.5 mm. Our excellent study results indicate that larger grafts are unnecessary. Mihata and colleagues¹⁰ used fascia lata grafts of 6 mm to 8 mm. Ultimate load to failure is significantly higher for dermal allograft than for fascia lata graft.²⁵ In SCR, the stronger dermal allograft withstands applied forces and repeated deformations and has excellent clinical outcomes.

Only 1 patient had a failure that required RTSA. VAS pain scores were lower and ASES scores were improved the first year after surgery, but then function deteriorated. The patient said there was no specific precipitating incident. Computed tomography arthrogram, ordered to assess the construct, showed anterior and superior subluxation of the humeral head, even with an intact subscapularis tendon—an indication of underlying instability, which most likely caused the failure. Eighteen months after surgery, the patient was able to undergo RTSA. On further evaluation of this patient’s procedure, it was determined that the graft needed better fixation anteriorly.

Mihata and colleagues^10,12,14 indicated that AMC was unnecessary, and our procedure did not require it. However, data in our prospective evaluation began showing improved outcomes with AMC. As dermal allograft is more elastic than fascia lata autograft,²⁵ we concluded that graft tensioning is key to the success of this procedure. Graft tension depends on many factors, including exact measurement of the distances between the anchors to punch holes in the graft, arm position to set the relationship between the anchor distances, and AMC and PMC. We recommend placing the arm in neutral rotation, neutral flexion, and abduction with the patient at rest, based on the size of the patient’s latissimus dorsi. Too much abduction causes overtensioning, and excess rotation or flexion-extension changes the distance between the glenoid and the greater tuberosity asymmetrically, from anterior to posterior. With the arm in neutral position, distances between anchors are accurately measured, and these measurements are used to determine graft size.

Graft tension is also needed to control the amount of elasticity allowed by the graft and thereby maintain stability, as shown by the Poisson ratio, the ratio of transverse contraction to longitudinal extension on a material in the presence of a stretching force. As applied to SCR, it is the ratio of mediolateral elasticity to anteroposterior deformation or constraint. If the graft is appropriately secured in the anteroposterior direction by way of ACM and PMC, elongation in the medial-lateral direction will be limited—reducing the elasticity of the graft, improving overall stability, and ultimately producing better clinical outcomes. This issue was discussed by Burkhart and colleagues²⁶ with respect to the “rotator cable complex,” which now might be best described as the “rotator-capsule cable complex.” In our study, this phenomenon was evident in the finding that patients who had AMC performed did significantly better than patients who did not have AMC performed. The ability of dermal allograft to deform in these dimensions without failure while allowing excellent range of motion makes dermal allograft an exceptional choice for grafting during SCR. Mihata25 also found dermal allograft had a clear advantage in providing better range of motion, whereas fascia lata autograft resulted in a stiffer construct. 

Dermal allograft can also incorporate into the body and transform into host tissue. The literature has described musculoskeletal US as an effective diagnostic and interventional tool.^27-31 We used it to evaluate graft size, patency, and viability. As can be seen on US, the native rotator cuff does not have any pulsatile vessels and is fed by capillary flow. Dermal allograft has native vasculature built into the tissue. After 4 months to 8 months, presence of pulsatile vessels within the graft at the greater tuberosity indicates clear revascularization and incorporation of the tissue (Figure 6B). Disappearance of pulsatile vessels on US after 1 year indicates transformation to a stabilizing structure analogous to capsule or ligament with capillary flow. US also showed graft hypertrophy after 2 years, supporting a finding of integration and growth.

Conclusion

In the past, patients with irreparable massive RCTs had few good surgical management options, RTSA being the most definitive. SCR is technically challenging and requires use of specific implantation methods but can provide patients with outstanding relief. Our clinical data showed that technically well executed SCR effectively restores the superior restraints in the glenohumeral joint and thereby increases function and decreases pain in patients with irreparable massive RCTs, even after 2 years.

Take-Home Points

• Use ultrasound to identify integrity and location of MPFL tear.
• Anatomic repair allows native tissue to reintegrate into bone.
• Repairs done early can prevent complications of recurrent instability.
• Repair maintains biological and proprioceptive qualities of tissue.

• 10Ultrasound-guided percutaneous repair is quick and effective.

The medial patellofemoral ligament (MPFL) is the primary passive restraint to lateral patellar excursion^1-5 and helps control patellar tilt and rotation.^6,7 More than 90% of lateral patellar dislocations cause the MPFL to rupture, and roughly 90% of these detachments involve the femoral insertion.⁴ Ensuing patellar instability often results from MPFL insufficiency. It has been suggested that re-creating the anatomy and functionality of this ligament is of utmost importance in restoring normal patellar biomechanics.^1-5,7,8

Anatomical risk factors for recurrent patellar instability include patella alta, increased tibial tuberosity-trochlear groove (TT-TG) distance, trochlear dysplasia, and torsional abnormalities.^1-4,6 A medial reefing technique with a lateral tissue release traditionally was used to restore proper kinematics, but was shown to have associated postoperative issues.⁹

Methods

Patient Demographics

Dr. Hirahara developed this technique in 2013 and performed it 11 times between 2013 and 2016. Of the 11 patients, 1 was excluded from our retrospective analysis because of trochlear dysplasia, now considered a relative contraindication. Of the remaining 10 patients, 5 (50%) had the repair performed on the right knee. Eight patients (80%) were female. Mean (SD) age was 17.21 (3.53) years. One patient had concurrent femur- and patella-side detachments; otherwise, 6 (60%) of 10 repairs were performed exclusively at the patella. We grade patellar instability according to amount of glide based on patellar width and quadrants. Normal lateral displacement was usually 1 to 2 quadrants of lateral glide relative to the contralateral side. Before surgery, 6 (60%) of the 10 patients presented with lateral glide of 3 quadrants, and 3 (30%) presented with lateral glide of 4 quadrants. All had patellar instability apprehension on physical examination.

Surgical Indications

Before surgery, MPFL integrity is determined by ultrasound evaluation. Repair is considered if the MPFL has a femur- or patella-side tear and is of adequate quantity and quality, and if there are minimal or no arthritic changes (Table 2).

Surgical Technique

The patient is brought to the operating room and placed supine. Patellar stability of the affected knee is assessed and compared with that of the contralateral side with patellar glide. The knee is prepared and draped in usual sterile fashion. With the knee flexed at 90º, a tourniquet is inflated. Diagnostic arthroscopy is performed with standard anteromedial and anterolateral portals, and, if necessary, arthroscopic procedures are performed.

Femoral Attachment Repair

With the leg in extension, ultrasound is used to identify the tear at the femoral attachment (watch part 1 of the video). A spinal needle is placed at the femoral insertion, typically just anterior and distal to the adductor tubercle (Figure 4).¹⁰

Patellar Attachment Repair

With the leg in extension, ultrasound is used to identify where the MPFL is detached from the patella (watch part 2 of the video). A spinal needle is placed at the detachment site (Figure 5). A scalpel is used to make a 1-cm incision down to the patella.

In this description, we showcase knotless and knotted techniques for each repair site. Either method is appropriate for the 2 repair sites. Owing to the superficial nature of the attachment sites—they may have very little fat, particularly at the patella—knot stacks are more prominent, can be felt after surgery, and have the potential to irritate surrounding tissues. Therefore, we prefer knotless fixation for both sites.

Rehabilitation

Rehabilitation after MPFL repair is much like rehabilitation after quadriceps tendon repair. The patient is locked in a brace in full extension when up and moving. Early weight-bearing and minimal use of assistive devices (crutches) are allowed because, when the leg is in full extension, there is no tension at the repair sites. Rehabilitation begins within 1 week, and normal daily function is quickly attained. The protocol emphasizes pain-free motion and suitable patellar mobility, and allows the immobilizing brace to be unlocked for exercise and sitting. During the first 4 weeks, quadriceps activation is limited; progression to full ROM occurs by 4 to 6 weeks. During the strengthening phase, loading the knee in early flexion should be avoided. Return to heavy lifting, physical activity, and sports is delayed until after 6 months in order to allow the construct to mature and integrate. Once the patient has satisfied all the strength, ROM, and functional outcome measurements, a brace is no longer required during sports and normal activity.

Results

Mean tourniquet time for each procedure, which includes diagnostic arthroscopy and ultrasound-guided percutaneous repair, was 26.9 minutes.

Discussion

Conservative management typically is recommended for acute patellar dislocations. In the event of failed conservative management or chronic patellar instability, surgical intervention is indicated. Studies have found that conservative management has recurrent-dislocation rates of 35% at 3-year follow-up and 73% at 6-year follow-up, and recurrent dislocations significantly increase patients’ risk of developing chondral and bony damage.¹³ MPFL repair is designed to restore proper patellar tracking and kinematics while maintaining the anatomical tissue. Lateral patellar dislocations often cause the MPFL to rupture; tears are reported in more than 90% of incidents.⁴ The significant rate indicates that, even after a single patellar dislocation, the MPFL should be evaluated. The MPFL contributes 50% to 60% of the medial stabilizing force during patellar tracking^1,7,14 and is the primary restraint to lateral patellar excursion and excessive patellar tilt and rotation.^1-5 Its absence plays a key role in recurrent lateral patellar instability. With this structure being so important, proper identification and intervention are vital. Studies have established that redislocation rates are significantly higher for nonoperatively (vs operatively) treated primary patellar dislocations.¹³ Simple and accurate percutaneous repair of the MPFL should be performed early to avoid the long-term complications of recurrent instability that could damage the cartilage and bone of the patella and trochlea.

The primary advantage of this technique is its novel use of musculoskeletal ultrasound to accurately identify anatomy and pathology and the placement of anatomical repairs. Accurate preoperative and intraoperative assessment of MPFL anatomy is vital to the success of a procedure. Descriptions of MPFL anatomy suggest discrepancies in the exact locations of the femoral and patellar attachments.^{2,5,7,10,12,15,16} Tanaka⁵ noted that, even within paired knees, there was “marked variability” in the MPFL insertions. McCarthy and colleagues¹⁰ contended the femoral attachment of the MPFL is just anterior and distal to the adductor tubercle, the landmark addressed in this technique. Steensen and colleagues¹⁶ described this attachment site as being statistically the “single most important point affecting isometry” of the MPFL. Sallay and colleagues⁴ asserted that an overwhelming majority of MPFL tears (87%) occur at the adductor tubercle. The variable distribution of tear locations and the importance of re-creating patient anatomy further highlight the need for individualized treatment, which is afforded by ultrasound. Fluoroscopy has been inadequate in identifying MPFL anatomy; this modality is difficult, cumbersome, inaccurate, and inconsistent.^11,12 Conversely, ultrasound provides real-time visualization of anatomy and allows for precise identification of MPFL attachments and accurate placement of suture anchors for repair during surgery (Figures 3, 4).

For femur-side and patella-side tears, repairs can and should be performed. For midsubstance tears, however, repair is not feasible, and reconstruction is appropriate. MPFL repair is superior to reconstruction in several ways. Repair is a simple percutaneous procedure that had a mean tourniquet time of 26.9 minutes in this study. For tissue that is quantitatively and qualitatively adequate, repair allows the structure to reintegrate into bone without total reconstruction. In the event of multiple tears, the percutaneous procedure allows for repair of each attachment. As the MPFL sits between the second and third tissue layers of the medial knee, reconstruction can be difficult and invasive and require establishment of a between-layers plane, which can disrupt adjacent tissue.^4,7,17 Repair also maintains native tissue and its neurovascular and proprioceptive properties.

Reconstruction of the MPFL has become the gold-standard treatment for recurrent lateral patellar instability but has limitations and complications.^3,7,12,17 Reconstruction techniques use either surface anatomy palpation (requiring large incisions) or fluoroscopy to identify tunnel placement locations, and accurate placement has often been difficult and inconsistent. Our repair technique has several advantages over reconstruction. It does not burn any bridges; it allows for subsequent reconstruction. It does not require a graft and, using small suture anchors instead of large sockets and anchors, involves less bone loss. It also allows for early repair of tears—patients can return to activities, sports, and work quicker—and avoids the risk of chondral and bony damage with recurrent dislocations. According to our review of the MPFL repairs performed by Dr. Hirahara starting in 2013, the procedure is quick and successful and has outstanding outcomes.

Another treatment option for recurrent lateral patellar instability combines reefing of the medial patellofemoral tissues with a lateral release. This combination has had several postoperative complications and is no longer indicated.⁹ TT transfer and trochleoplasty procedures have been developed to address different aspects of patellar instability, increased TT-TG distance, and dysplastic trochlea (Table 2). Both types of procedures are highly invasive and difficult to perform, requiring technical expertise. They are best used when warranted by the anatomy, but this is uncommon. The technique we have presented allows for easy and reliable repair of dislocations in the absence of associated pathology that would require larger, more complex surgery. The ease of use and accuracy of musculoskeletal ultrasound make this technique superior to others.

Conclusion

The MPFL is a vital static stabilizer of the patella and as such should be evaluated in the setting of patellar injury. The novel preoperative and intraoperative use of musculoskeletal ultrasound described in this article allows for easy real-time identification of the MPFL and simple and accurate percutaneous repair of torn structures. Nonoperative treatments of acute patellar dislocations have higher rates of recurrent dislocations, which put patella and trochlea at risk for bony and chondral damage. Given appropriate tear location and tissue quality, repairs should be considered early and before reconstruction. To our knowledge, a reliable, easily reproducible MPFL repair was not described until now. We have reported on use of such a technique and on its promising patient outcomes, which should be considered when addressing MPFL injuries.

Am J Orthop. 2017;46(3):152-157. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• Use ultrasound to identify integrity and location of MPFL tear.
• Anatomic repair allows native tissue to reintegrate into bone.
• Repairs done early can prevent complications of recurrent instability.
• Repair maintains biological and proprioceptive qualities of tissue.

• 10Ultrasound-guided percutaneous repair is quick and effective.

The medial patellofemoral ligament (MPFL) is the primary passive restraint to lateral patellar excursion^1-5 and helps control patellar tilt and rotation.^6,7 More than 90% of lateral patellar dislocations cause the MPFL to rupture, and roughly 90% of these detachments involve the femoral insertion.⁴ Ensuing patellar instability often results from MPFL insufficiency. It has been suggested that re-creating the anatomy and functionality of this ligament is of utmost importance in restoring normal patellar biomechanics.^1-5,7,8

Anatomical risk factors for recurrent patellar instability include patella alta, increased tibial tuberosity-trochlear groove (TT-TG) distance, trochlear dysplasia, and torsional abnormalities.^1-4,6 A medial reefing technique with a lateral tissue release traditionally was used to restore proper kinematics, but was shown to have associated postoperative issues.⁹

Methods

Patient Demographics

Dr. Hirahara developed this technique in 2013 and performed it 11 times between 2013 and 2016. Of the 11 patients, 1 was excluded from our retrospective analysis because of trochlear dysplasia, now considered a relative contraindication. Of the remaining 10 patients, 5 (50%) had the repair performed on the right knee. Eight patients (80%) were female. Mean (SD) age was 17.21 (3.53) years. One patient had concurrent femur- and patella-side detachments; otherwise, 6 (60%) of 10 repairs were performed exclusively at the patella. We grade patellar instability according to amount of glide based on patellar width and quadrants. Normal lateral displacement was usually 1 to 2 quadrants of lateral glide relative to the contralateral side. Before surgery, 6 (60%) of the 10 patients presented with lateral glide of 3 quadrants, and 3 (30%) presented with lateral glide of 4 quadrants. All had patellar instability apprehension on physical examination.

Surgical Indications

Before surgery, MPFL integrity is determined by ultrasound evaluation. Repair is considered if the MPFL has a femur- or patella-side tear and is of adequate quantity and quality, and if there are minimal or no arthritic changes (Table 2).

Surgical Technique

The patient is brought to the operating room and placed supine. Patellar stability of the affected knee is assessed and compared with that of the contralateral side with patellar glide. The knee is prepared and draped in usual sterile fashion. With the knee flexed at 90º, a tourniquet is inflated. Diagnostic arthroscopy is performed with standard anteromedial and anterolateral portals, and, if necessary, arthroscopic procedures are performed.

Femoral Attachment Repair

With the leg in extension, ultrasound is used to identify the tear at the femoral attachment (watch part 1 of the video). A spinal needle is placed at the femoral insertion, typically just anterior and distal to the adductor tubercle (Figure 4).¹⁰

Patellar Attachment Repair

With the leg in extension, ultrasound is used to identify where the MPFL is detached from the patella (watch part 2 of the video). A spinal needle is placed at the detachment site (Figure 5). A scalpel is used to make a 1-cm incision down to the patella.

In this description, we showcase knotless and knotted techniques for each repair site. Either method is appropriate for the 2 repair sites. Owing to the superficial nature of the attachment sites—they may have very little fat, particularly at the patella—knot stacks are more prominent, can be felt after surgery, and have the potential to irritate surrounding tissues. Therefore, we prefer knotless fixation for both sites.

Rehabilitation

Rehabilitation after MPFL repair is much like rehabilitation after quadriceps tendon repair. The patient is locked in a brace in full extension when up and moving. Early weight-bearing and minimal use of assistive devices (crutches) are allowed because, when the leg is in full extension, there is no tension at the repair sites. Rehabilitation begins within 1 week, and normal daily function is quickly attained. The protocol emphasizes pain-free motion and suitable patellar mobility, and allows the immobilizing brace to be unlocked for exercise and sitting. During the first 4 weeks, quadriceps activation is limited; progression to full ROM occurs by 4 to 6 weeks. During the strengthening phase, loading the knee in early flexion should be avoided. Return to heavy lifting, physical activity, and sports is delayed until after 6 months in order to allow the construct to mature and integrate. Once the patient has satisfied all the strength, ROM, and functional outcome measurements, a brace is no longer required during sports and normal activity.

Results

Mean tourniquet time for each procedure, which includes diagnostic arthroscopy and ultrasound-guided percutaneous repair, was 26.9 minutes.

Discussion

Conservative management typically is recommended for acute patellar dislocations. In the event of failed conservative management or chronic patellar instability, surgical intervention is indicated. Studies have found that conservative management has recurrent-dislocation rates of 35% at 3-year follow-up and 73% at 6-year follow-up, and recurrent dislocations significantly increase patients’ risk of developing chondral and bony damage.¹³ MPFL repair is designed to restore proper patellar tracking and kinematics while maintaining the anatomical tissue. Lateral patellar dislocations often cause the MPFL to rupture; tears are reported in more than 90% of incidents.⁴ The significant rate indicates that, even after a single patellar dislocation, the MPFL should be evaluated. The MPFL contributes 50% to 60% of the medial stabilizing force during patellar tracking^1,7,14 and is the primary restraint to lateral patellar excursion and excessive patellar tilt and rotation.^1-5 Its absence plays a key role in recurrent lateral patellar instability. With this structure being so important, proper identification and intervention are vital. Studies have established that redislocation rates are significantly higher for nonoperatively (vs operatively) treated primary patellar dislocations.¹³ Simple and accurate percutaneous repair of the MPFL should be performed early to avoid the long-term complications of recurrent instability that could damage the cartilage and bone of the patella and trochlea.

The primary advantage of this technique is its novel use of musculoskeletal ultrasound to accurately identify anatomy and pathology and the placement of anatomical repairs. Accurate preoperative and intraoperative assessment of MPFL anatomy is vital to the success of a procedure. Descriptions of MPFL anatomy suggest discrepancies in the exact locations of the femoral and patellar attachments.^{2,5,7,10,12,15,16} Tanaka⁵ noted that, even within paired knees, there was “marked variability” in the MPFL insertions. McCarthy and colleagues¹⁰ contended the femoral attachment of the MPFL is just anterior and distal to the adductor tubercle, the landmark addressed in this technique. Steensen and colleagues¹⁶ described this attachment site as being statistically the “single most important point affecting isometry” of the MPFL. Sallay and colleagues⁴ asserted that an overwhelming majority of MPFL tears (87%) occur at the adductor tubercle. The variable distribution of tear locations and the importance of re-creating patient anatomy further highlight the need for individualized treatment, which is afforded by ultrasound. Fluoroscopy has been inadequate in identifying MPFL anatomy; this modality is difficult, cumbersome, inaccurate, and inconsistent.^11,12 Conversely, ultrasound provides real-time visualization of anatomy and allows for precise identification of MPFL attachments and accurate placement of suture anchors for repair during surgery (Figures 3, 4).

For femur-side and patella-side tears, repairs can and should be performed. For midsubstance tears, however, repair is not feasible, and reconstruction is appropriate. MPFL repair is superior to reconstruction in several ways. Repair is a simple percutaneous procedure that had a mean tourniquet time of 26.9 minutes in this study. For tissue that is quantitatively and qualitatively adequate, repair allows the structure to reintegrate into bone without total reconstruction. In the event of multiple tears, the percutaneous procedure allows for repair of each attachment. As the MPFL sits between the second and third tissue layers of the medial knee, reconstruction can be difficult and invasive and require establishment of a between-layers plane, which can disrupt adjacent tissue.^4,7,17 Repair also maintains native tissue and its neurovascular and proprioceptive properties.

Reconstruction of the MPFL has become the gold-standard treatment for recurrent lateral patellar instability but has limitations and complications.^3,7,12,17 Reconstruction techniques use either surface anatomy palpation (requiring large incisions) or fluoroscopy to identify tunnel placement locations, and accurate placement has often been difficult and inconsistent. Our repair technique has several advantages over reconstruction. It does not burn any bridges; it allows for subsequent reconstruction. It does not require a graft and, using small suture anchors instead of large sockets and anchors, involves less bone loss. It also allows for early repair of tears—patients can return to activities, sports, and work quicker—and avoids the risk of chondral and bony damage with recurrent dislocations. According to our review of the MPFL repairs performed by Dr. Hirahara starting in 2013, the procedure is quick and successful and has outstanding outcomes.

Another treatment option for recurrent lateral patellar instability combines reefing of the medial patellofemoral tissues with a lateral release. This combination has had several postoperative complications and is no longer indicated.⁹ TT transfer and trochleoplasty procedures have been developed to address different aspects of patellar instability, increased TT-TG distance, and dysplastic trochlea (Table 2). Both types of procedures are highly invasive and difficult to perform, requiring technical expertise. They are best used when warranted by the anatomy, but this is uncommon. The technique we have presented allows for easy and reliable repair of dislocations in the absence of associated pathology that would require larger, more complex surgery. The ease of use and accuracy of musculoskeletal ultrasound make this technique superior to others.

Conclusion

The MPFL is a vital static stabilizer of the patella and as such should be evaluated in the setting of patellar injury. The novel preoperative and intraoperative use of musculoskeletal ultrasound described in this article allows for easy real-time identification of the MPFL and simple and accurate percutaneous repair of torn structures. Nonoperative treatments of acute patellar dislocations have higher rates of recurrent dislocations, which put patella and trochlea at risk for bony and chondral damage. Given appropriate tear location and tissue quality, repairs should be considered early and before reconstruction. To our knowledge, a reliable, easily reproducible MPFL repair was not described until now. We have reported on use of such a technique and on its promising patient outcomes, which should be considered when addressing MPFL injuries.

Am J Orthop. 2017;46(3):152-157. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Take-Home Points

• Use ultrasound to identify integrity and location of MPFL tear.
• Anatomic repair allows native tissue to reintegrate into bone.
• Repairs done early can prevent complications of recurrent instability.
• Repair maintains biological and proprioceptive qualities of tissue.

• 10Ultrasound-guided percutaneous repair is quick and effective.

The medial patellofemoral ligament (MPFL) is the primary passive restraint to lateral patellar excursion^1-5 and helps control patellar tilt and rotation.^6,7 More than 90% of lateral patellar dislocations cause the MPFL to rupture, and roughly 90% of these detachments involve the femoral insertion.⁴ Ensuing patellar instability often results from MPFL insufficiency. It has been suggested that re-creating the anatomy and functionality of this ligament is of utmost importance in restoring normal patellar biomechanics.^1-5,7,8

Anatomical risk factors for recurrent patellar instability include patella alta, increased tibial tuberosity-trochlear groove (TT-TG) distance, trochlear dysplasia, and torsional abnormalities.^1-4,6 A medial reefing technique with a lateral tissue release traditionally was used to restore proper kinematics, but was shown to have associated postoperative issues.⁹

Methods

Patient Demographics

Dr. Hirahara developed this technique in 2013 and performed it 11 times between 2013 and 2016. Of the 11 patients, 1 was excluded from our retrospective analysis because of trochlear dysplasia, now considered a relative contraindication. Of the remaining 10 patients, 5 (50%) had the repair performed on the right knee. Eight patients (80%) were female. Mean (SD) age was 17.21 (3.53) years. One patient had concurrent femur- and patella-side detachments; otherwise, 6 (60%) of 10 repairs were performed exclusively at the patella. We grade patellar instability according to amount of glide based on patellar width and quadrants. Normal lateral displacement was usually 1 to 2 quadrants of lateral glide relative to the contralateral side. Before surgery, 6 (60%) of the 10 patients presented with lateral glide of 3 quadrants, and 3 (30%) presented with lateral glide of 4 quadrants. All had patellar instability apprehension on physical examination.

Surgical Indications

Before surgery, MPFL integrity is determined by ultrasound evaluation. Repair is considered if the MPFL has a femur- or patella-side tear and is of adequate quantity and quality, and if there are minimal or no arthritic changes (Table 2).

Surgical Technique

The patient is brought to the operating room and placed supine. Patellar stability of the affected knee is assessed and compared with that of the contralateral side with patellar glide. The knee is prepared and draped in usual sterile fashion. With the knee flexed at 90º, a tourniquet is inflated. Diagnostic arthroscopy is performed with standard anteromedial and anterolateral portals, and, if necessary, arthroscopic procedures are performed.

Femoral Attachment Repair

With the leg in extension, ultrasound is used to identify the tear at the femoral attachment (watch part 1 of the video). A spinal needle is placed at the femoral insertion, typically just anterior and distal to the adductor tubercle (Figure 4).¹⁰

Patellar Attachment Repair

With the leg in extension, ultrasound is used to identify where the MPFL is detached from the patella (watch part 2 of the video). A spinal needle is placed at the detachment site (Figure 5). A scalpel is used to make a 1-cm incision down to the patella.

In this description, we showcase knotless and knotted techniques for each repair site. Either method is appropriate for the 2 repair sites. Owing to the superficial nature of the attachment sites—they may have very little fat, particularly at the patella—knot stacks are more prominent, can be felt after surgery, and have the potential to irritate surrounding tissues. Therefore, we prefer knotless fixation for both sites.

Rehabilitation

Rehabilitation after MPFL repair is much like rehabilitation after quadriceps tendon repair. The patient is locked in a brace in full extension when up and moving. Early weight-bearing and minimal use of assistive devices (crutches) are allowed because, when the leg is in full extension, there is no tension at the repair sites. Rehabilitation begins within 1 week, and normal daily function is quickly attained. The protocol emphasizes pain-free motion and suitable patellar mobility, and allows the immobilizing brace to be unlocked for exercise and sitting. During the first 4 weeks, quadriceps activation is limited; progression to full ROM occurs by 4 to 6 weeks. During the strengthening phase, loading the knee in early flexion should be avoided. Return to heavy lifting, physical activity, and sports is delayed until after 6 months in order to allow the construct to mature and integrate. Once the patient has satisfied all the strength, ROM, and functional outcome measurements, a brace is no longer required during sports and normal activity.

Results

Mean tourniquet time for each procedure, which includes diagnostic arthroscopy and ultrasound-guided percutaneous repair, was 26.9 minutes.

Discussion

Conservative management typically is recommended for acute patellar dislocations. In the event of failed conservative management or chronic patellar instability, surgical intervention is indicated. Studies have found that conservative management has recurrent-dislocation rates of 35% at 3-year follow-up and 73% at 6-year follow-up, and recurrent dislocations significantly increase patients’ risk of developing chondral and bony damage.¹³ MPFL repair is designed to restore proper patellar tracking and kinematics while maintaining the anatomical tissue. Lateral patellar dislocations often cause the MPFL to rupture; tears are reported in more than 90% of incidents.⁴ The significant rate indicates that, even after a single patellar dislocation, the MPFL should be evaluated. The MPFL contributes 50% to 60% of the medial stabilizing force during patellar tracking^1,7,14 and is the primary restraint to lateral patellar excursion and excessive patellar tilt and rotation.^1-5 Its absence plays a key role in recurrent lateral patellar instability. With this structure being so important, proper identification and intervention are vital. Studies have established that redislocation rates are significantly higher for nonoperatively (vs operatively) treated primary patellar dislocations.¹³ Simple and accurate percutaneous repair of the MPFL should be performed early to avoid the long-term complications of recurrent instability that could damage the cartilage and bone of the patella and trochlea.

The primary advantage of this technique is its novel use of musculoskeletal ultrasound to accurately identify anatomy and pathology and the placement of anatomical repairs. Accurate preoperative and intraoperative assessment of MPFL anatomy is vital to the success of a procedure. Descriptions of MPFL anatomy suggest discrepancies in the exact locations of the femoral and patellar attachments.^{2,5,7,10,12,15,16} Tanaka⁵ noted that, even within paired knees, there was “marked variability” in the MPFL insertions. McCarthy and colleagues¹⁰ contended the femoral attachment of the MPFL is just anterior and distal to the adductor tubercle, the landmark addressed in this technique. Steensen and colleagues¹⁶ described this attachment site as being statistically the “single most important point affecting isometry” of the MPFL. Sallay and colleagues⁴ asserted that an overwhelming majority of MPFL tears (87%) occur at the adductor tubercle. The variable distribution of tear locations and the importance of re-creating patient anatomy further highlight the need for individualized treatment, which is afforded by ultrasound. Fluoroscopy has been inadequate in identifying MPFL anatomy; this modality is difficult, cumbersome, inaccurate, and inconsistent.^11,12 Conversely, ultrasound provides real-time visualization of anatomy and allows for precise identification of MPFL attachments and accurate placement of suture anchors for repair during surgery (Figures 3, 4).

For femur-side and patella-side tears, repairs can and should be performed. For midsubstance tears, however, repair is not feasible, and reconstruction is appropriate. MPFL repair is superior to reconstruction in several ways. Repair is a simple percutaneous procedure that had a mean tourniquet time of 26.9 minutes in this study. For tissue that is quantitatively and qualitatively adequate, repair allows the structure to reintegrate into bone without total reconstruction. In the event of multiple tears, the percutaneous procedure allows for repair of each attachment. As the MPFL sits between the second and third tissue layers of the medial knee, reconstruction can be difficult and invasive and require establishment of a between-layers plane, which can disrupt adjacent tissue.^4,7,17 Repair also maintains native tissue and its neurovascular and proprioceptive properties.

Reconstruction of the MPFL has become the gold-standard treatment for recurrent lateral patellar instability but has limitations and complications.^3,7,12,17 Reconstruction techniques use either surface anatomy palpation (requiring large incisions) or fluoroscopy to identify tunnel placement locations, and accurate placement has often been difficult and inconsistent. Our repair technique has several advantages over reconstruction. It does not burn any bridges; it allows for subsequent reconstruction. It does not require a graft and, using small suture anchors instead of large sockets and anchors, involves less bone loss. It also allows for early repair of tears—patients can return to activities, sports, and work quicker—and avoids the risk of chondral and bony damage with recurrent dislocations. According to our review of the MPFL repairs performed by Dr. Hirahara starting in 2013, the procedure is quick and successful and has outstanding outcomes.

Another treatment option for recurrent lateral patellar instability combines reefing of the medial patellofemoral tissues with a lateral release. This combination has had several postoperative complications and is no longer indicated.⁹ TT transfer and trochleoplasty procedures have been developed to address different aspects of patellar instability, increased TT-TG distance, and dysplastic trochlea (Table 2). Both types of procedures are highly invasive and difficult to perform, requiring technical expertise. They are best used when warranted by the anatomy, but this is uncommon. The technique we have presented allows for easy and reliable repair of dislocations in the absence of associated pathology that would require larger, more complex surgery. The ease of use and accuracy of musculoskeletal ultrasound make this technique superior to others.

Conclusion

The MPFL is a vital static stabilizer of the patella and as such should be evaluated in the setting of patellar injury. The novel preoperative and intraoperative use of musculoskeletal ultrasound described in this article allows for easy real-time identification of the MPFL and simple and accurate percutaneous repair of torn structures. Nonoperative treatments of acute patellar dislocations have higher rates of recurrent dislocations, which put patella and trochlea at risk for bony and chondral damage. Given appropriate tear location and tissue quality, repairs should be considered early and before reconstruction. To our knowledge, a reliable, easily reproducible MPFL repair was not described until now. We have reported on use of such a technique and on its promising patient outcomes, which should be considered when addressing MPFL injuries.

Am J Orthop. 2017;46(3):152-157. Copyright Frontline Medical Communications Inc. 2017. All rights reserved.

Video, Part 1. Femoral Attachment

1. Ultrasound is used to identify femoral and patellar attachments of medial patellofemoral ligament (MPFL).

2. MPFL is followed from patella to its attachment near adductor tubercle.

3. In-plane ultrasound guidance is used to place needle anterior and distal to tubercle.

4. Percutaneous incision is made down to needle tip. Spear is placed at needle tip for anatomical placement of socket.

5. Socket is drilled.

6. 3.0-mm suture anchor (BioComposite Knotless SutureTak; Arthrex) is placed.

7. Leading edge of torn MPFL is identified.

8. Suture passer (Labral FastPass Scorpion; Arthrex) is used to pass sutures through leading edge of torn MPFL to create horizontal mattress.

9. Sutures are tied.

10. Repair is complete.

Video, Part 2. Patellar Attachment

1. Ultrasound is used to scan patella to identify ideal or exact location of tear. In-plane ultrasound guidance is used to place spinal needle at desired socket location.

2. After spinal needle is positioned, in-line percutaneous incision is made, and needle is palpated at patella.

3. Spear is then placed at spinal needle tip for anatomical positioning of socket.

4. Socket is drilled.

5. 3.0-mm suture anchor (BioComposite Knotless SutureTak; Arthrex) is placed in socket.

6. Leading edge of torn medial patellofemoral ligament (MPFL) is identified.

7. Suture passer (Labral Past Pass Scorpion; Arthrex) is used to pass suture from anchor in horizontal mattress fashion through leading edge of torn MPFL.

8. Wire with loop (FiberSnare; Arthrex) is used as part of knotless technology to pull suture back through anchor to create knotless fixation.

9. Suture is pulled for appropriate tensioning of tissue.

10. Ultrasound is used to visualize construct to confirm that MPFL tissue abuts anchor and that repair is complete.

Video, Part 1. Femoral Attachment

1. Ultrasound is used to identify femoral and patellar attachments of medial patellofemoral ligament (MPFL).

2. MPFL is followed from patella to its attachment near adductor tubercle.

3. In-plane ultrasound guidance is used to place needle anterior and distal to tubercle.

4. Percutaneous incision is made down to needle tip. Spear is placed at needle tip for anatomical placement of socket.

5. Socket is drilled.

6. 3.0-mm suture anchor (BioComposite Knotless SutureTak; Arthrex) is placed.

7. Leading edge of torn MPFL is identified.

8. Suture passer (Labral FastPass Scorpion; Arthrex) is used to pass sutures through leading edge of torn MPFL to create horizontal mattress.

9. Sutures are tied.

10. Repair is complete.

Video, Part 2. Patellar Attachment

1. Ultrasound is used to scan patella to identify ideal or exact location of tear. In-plane ultrasound guidance is used to place spinal needle at desired socket location.

2. After spinal needle is positioned, in-line percutaneous incision is made, and needle is palpated at patella.

3. Spear is then placed at spinal needle tip for anatomical positioning of socket.

4. Socket is drilled.

5. 3.0-mm suture anchor (BioComposite Knotless SutureTak; Arthrex) is placed in socket.

6. Leading edge of torn medial patellofemoral ligament (MPFL) is identified.

7. Suture passer (Labral Past Pass Scorpion; Arthrex) is used to pass suture from anchor in horizontal mattress fashion through leading edge of torn MPFL.

8. Wire with loop (FiberSnare; Arthrex) is used as part of knotless technology to pull suture back through anchor to create knotless fixation.

9. Suture is pulled for appropriate tensioning of tissue.

10. Ultrasound is used to visualize construct to confirm that MPFL tissue abuts anchor and that repair is complete.

Video, Part 1. Femoral Attachment

1. Ultrasound is used to identify femoral and patellar attachments of medial patellofemoral ligament (MPFL).

2. MPFL is followed from patella to its attachment near adductor tubercle.

3. In-plane ultrasound guidance is used to place needle anterior and distal to tubercle.

4. Percutaneous incision is made down to needle tip. Spear is placed at needle tip for anatomical placement of socket.

5. Socket is drilled.

6. 3.0-mm suture anchor (BioComposite Knotless SutureTak; Arthrex) is placed.

7. Leading edge of torn MPFL is identified.

8. Suture passer (Labral FastPass Scorpion; Arthrex) is used to pass sutures through leading edge of torn MPFL to create horizontal mattress.

9. Sutures are tied.

10. Repair is complete.

Video, Part 2. Patellar Attachment

1. Ultrasound is used to scan patella to identify ideal or exact location of tear. In-plane ultrasound guidance is used to place spinal needle at desired socket location.

2. After spinal needle is positioned, in-line percutaneous incision is made, and needle is palpated at patella.

3. Spear is then placed at spinal needle tip for anatomical positioning of socket.

4. Socket is drilled.

5. 3.0-mm suture anchor (BioComposite Knotless SutureTak; Arthrex) is placed in socket.

6. Leading edge of torn medial patellofemoral ligament (MPFL) is identified.

7. Suture passer (Labral Past Pass Scorpion; Arthrex) is used to pass suture from anchor in horizontal mattress fashion through leading edge of torn MPFL.

8. Wire with loop (FiberSnare; Arthrex) is used as part of knotless technology to pull suture back through anchor to create knotless fixation.

9. Suture is pulled for appropriate tensioning of tissue.

10. Ultrasound is used to visualize construct to confirm that MPFL tissue abuts anchor and that repair is complete.

Arthrex Synergy MSK Ultrasound by Clarius(http://www.synergy-ultrasound.com/)

Arthrex Synergy MSK Ultrasound by Clarius is a new wireless ultrasound scanner that can connect to any iOS or Android device through a secure WiFi Direct connection. The scanner sets up the connection to an app on the device. Ultrasound and wireless technology have been around for decades, but combinations thereof have produced poor results. The main challenge has been to create and wirelessly transmit high-quality images without latency to a display while maintaining a reasonably sized transducer. Handheld ultrasound transducers scan effectively and process the scanned information in compact form. Recent advances in image processing and proprietary imaging algorithms now allow creation of high-resolution images comparable to those produced by most midrange or high-range machines costing $30,000 to $50,000. This new unit costs about $12,000. Ultrasound use has increased over the past decade. Numerous studies have found improved accuracy, efficacy, and outcomes of injections, and reduced pain, with ultrasound-guided injections over blind injections, and cost savings over magnetic resonance imaging.^1-12

Three scanners are capable of targeting different tissue types and depths. We prefer the Synergy MSK Linear Ultrasound by Clarius, a linear transducer that can evaluate tissue to depths of 7 cm and use frequencies from 4 MHz to 13 MHz. Its battery holds a standby charge for 7 days and can be actively used for 45 minutes. The unit has a magnesium shell; with the battery removed, the unit can be completely immersed in liquid without being damaged, which allows for easy cleaning and, potentially, sterilization with a soak solution. Color Doppler (for blood-flow assessment) and proprietary advanced needle visualization technology will be available in June.

The app is simply controlled with typical smart-device gestures. Depth control requires a finger swipe, and zoom takes a pinch. Other controls, such as optimal gain and frequency settings, are automated. Images and videos can be stored on the device and uploaded either to the Clarius Cloud or to a PACS (picture archiving and communication system) device. New features will allow the device to use a Synergy arthroscopy tower (Arthrex) as its display for surgeons and anesthesiologists in the surgical suite.

This technology finally allows ultrasound to be used in the operating room without the hassles of cumbersome machines and the potential contamination by the sleeves covering the cord that connects the transducer and the base unit (Figure 1).

Arthrex Synergy MSK Ultrasound by Clarius(http://www.synergy-ultrasound.com/)

Arthrex Synergy MSK Ultrasound by Clarius is a new wireless ultrasound scanner that can connect to any iOS or Android device through a secure WiFi Direct connection. The scanner sets up the connection to an app on the device. Ultrasound and wireless technology have been around for decades, but combinations thereof have produced poor results. The main challenge has been to create and wirelessly transmit high-quality images without latency to a display while maintaining a reasonably sized transducer. Handheld ultrasound transducers scan effectively and process the scanned information in compact form. Recent advances in image processing and proprietary imaging algorithms now allow creation of high-resolution images comparable to those produced by most midrange or high-range machines costing $30,000 to $50,000. This new unit costs about $12,000. Ultrasound use has increased over the past decade. Numerous studies have found improved accuracy, efficacy, and outcomes of injections, and reduced pain, with ultrasound-guided injections over blind injections, and cost savings over magnetic resonance imaging.^1-12

Three scanners are capable of targeting different tissue types and depths. We prefer the Synergy MSK Linear Ultrasound by Clarius, a linear transducer that can evaluate tissue to depths of 7 cm and use frequencies from 4 MHz to 13 MHz. Its battery holds a standby charge for 7 days and can be actively used for 45 minutes. The unit has a magnesium shell; with the battery removed, the unit can be completely immersed in liquid without being damaged, which allows for easy cleaning and, potentially, sterilization with a soak solution. Color Doppler (for blood-flow assessment) and proprietary advanced needle visualization technology will be available in June.

The app is simply controlled with typical smart-device gestures. Depth control requires a finger swipe, and zoom takes a pinch. Other controls, such as optimal gain and frequency settings, are automated. Images and videos can be stored on the device and uploaded either to the Clarius Cloud or to a PACS (picture archiving and communication system) device. New features will allow the device to use a Synergy arthroscopy tower (Arthrex) as its display for surgeons and anesthesiologists in the surgical suite.

This technology finally allows ultrasound to be used in the operating room without the hassles of cumbersome machines and the potential contamination by the sleeves covering the cord that connects the transducer and the base unit (Figure 1).

Arthrex Synergy MSK Ultrasound by Clarius(http://www.synergy-ultrasound.com/)

Arthrex Synergy MSK Ultrasound by Clarius is a new wireless ultrasound scanner that can connect to any iOS or Android device through a secure WiFi Direct connection. The scanner sets up the connection to an app on the device. Ultrasound and wireless technology have been around for decades, but combinations thereof have produced poor results. The main challenge has been to create and wirelessly transmit high-quality images without latency to a display while maintaining a reasonably sized transducer. Handheld ultrasound transducers scan effectively and process the scanned information in compact form. Recent advances in image processing and proprietary imaging algorithms now allow creation of high-resolution images comparable to those produced by most midrange or high-range machines costing $30,000 to $50,000. This new unit costs about $12,000. Ultrasound use has increased over the past decade. Numerous studies have found improved accuracy, efficacy, and outcomes of injections, and reduced pain, with ultrasound-guided injections over blind injections, and cost savings over magnetic resonance imaging.^1-12

Three scanners are capable of targeting different tissue types and depths. We prefer the Synergy MSK Linear Ultrasound by Clarius, a linear transducer that can evaluate tissue to depths of 7 cm and use frequencies from 4 MHz to 13 MHz. Its battery holds a standby charge for 7 days and can be actively used for 45 minutes. The unit has a magnesium shell; with the battery removed, the unit can be completely immersed in liquid without being damaged, which allows for easy cleaning and, potentially, sterilization with a soak solution. Color Doppler (for blood-flow assessment) and proprietary advanced needle visualization technology will be available in June.

The app is simply controlled with typical smart-device gestures. Depth control requires a finger swipe, and zoom takes a pinch. Other controls, such as optimal gain and frequency settings, are automated. Images and videos can be stored on the device and uploaded either to the Clarius Cloud or to a PACS (picture archiving and communication system) device. New features will allow the device to use a Synergy arthroscopy tower (Arthrex) as its display for surgeons and anesthesiologists in the surgical suite.

This technology finally allows ultrasound to be used in the operating room without the hassles of cumbersome machines and the potential contamination by the sleeves covering the cord that connects the transducer and the base unit (Figure 1).

Ultrasound has classically been marketed and used as a diagnostic tool. Radiologists, emergency physicians, and sports physicians used ultrasound units to rapidly and appropriately diagnose numerous injuries and disorders, in a timely and cost effective manner. Part 1¹ and Part 2² of this series showed how to use ultrasound in the shoulder for diagnosis and how to code and get reimbursed for its use.Ultrasound can also be used to help guide procedures and interventions performed to treat patients. Currently, more physicians are beginning to recognize the utility of this modality as an aid to interventional procedures.

First-generation procedures use ultrasound to improve accuracy of joint, bursal, tendon, and muscular injections.³ Recent studies have shown a significant improvement in accuracy, outcomes, and patient satisfaction using ultrasound guidance for injections.^3-12 Within the limitation of using a needle, second-generation procedures—hydrodissection of peripherally entrapped nerves, capsular distention, mechanical disruption of neovascularization, and needle fenestration or barbotage in chronic tendinopathy—try to simulate surgical objectives while minimizing tissue burden and other complications of surgery.³ More advanced procedures include needle fenestration/release of the carpal ligament in carpal tunnel syndrome and A1 pulley needle release in the setting of trigger finger.³ Innovative third-generation procedures involve the use of surgical tools such as hook blades under ultrasound guidance to perform surgical procedures. Surgeons are now improving already established percutaneous, arthroscopic, and open surgical procedures with ultrasound assistance.³ Aside from better guidance, reducing cost and improving surgeon comfort may be additional benefits of ultrasound assisted surgery.

Image-Guided Treatment Options

Prior to image guidance, palpation of surface anatomy helped physicians determine the anatomic placement of injections, incisions, or portals. Joints and bursas that do not have any inflammation or fluid can sometimes be difficult to identify or locate by palpation alone. Palpation-guided joint injections often miss their target and cause significant pain when the therapeutic agent is injected into a muscle, tendon, ligament, fat, or other tissue. Ultrasound-guided injections have proven to be more accurate and have better patient satisfaction when compared to blind injections.^3-12

X-ray fluoroscopy has been the primary option for surgeons to assist in surgery. This is a natural modality for orthopedic surgeons; their primary use is for bone to help with fracture reduction and fixation as the bone, instrumentation, and fixation methods are usually radio-opaque. With the advancement in technology, many orthopedic surgeons are regularly using radiolucent fixation devices and working with soft tissue as opposed to bone. Fixation of tendons, ligaments, and muscles would be done using a large incision, palpation of the anatomy, then fixation or repair. Many surgeons began looking for ways to minimize the incisions. Turning to fluoroscopy, a traditional and well-used modality, was a natural progression. Guides and methods were developed to isolate insertions and drill placements. However, fluoroscopy is limited by its difficulty in changing planes and the large equipment required. Also, it is limited in its ability to image soft tissue.

Computed tomography (CT) scans and magnetic resonance imaging (MRI) are far better at imaging soft tissue but cannot be taken for use into the office or surgical suite. These modalities are also far more expensive and take up significant space.

Ultrasound Procedural Basics

Appropriate use of ultrasound still remains highly technician-dependent. Unlike other imaging modalities, ultrasound requires a higher skill level by the physician to implement the use of ultrasound and identification of pathology to treat these disease processes. However, this is no different from the use of arthroscopy or fluoroscopy to treat patients. Training is required, as well as an understanding of the ultrasound machine, anatomy, and sono-anatomy—identification of anatomy and pathology as shown by the ultrasound machine.²

In ultrasound, the long axis refers to looking at a structure along its length, as in longitudinal. The short axis refers to evaluating a structure in cross-section, transverse, or along its shortest length. “In plane” refers to performing a procedure where the needle or object being used enters the ultrasound field along the plane of the transducer, allowing visualization of the majority of the needle as it crosses tissue planes. “Out of plane” has the needle entering perpendicular to the plane of the transducer, showing the needle on the monitor as a bright, hyperechoic dot. Some studies have suggested that novice ultrasonographers should start in a long axis view and use the in plane technique when injecting, as doing so may decrease time to identify the target and improve mean imaging quality during needle advancement.¹³

Anisotropy is the property of being directionally dependent. The ultrasound beam needs to be perpendicular to the structure being imaged to give the optimal image. When the beam hits a longitudinal structure like a needle at an angle <90°, the linear structure might reflect most of the beam away from the transducer. So when using a needle to localize or inject a specific area, maintaining the probe as close to perpendicular as possible with the needle will give a better image. New technology exists to better visualize needles even at high acuity angles by using a multi-beam processing algorithm, which can significantly aid the physician without the need for specialized needles.

Despite better technology, advance planning is key to a successful procedure. Positioning the patient and ultrasound machine in a manner that is comfortable and makes the desired target accessible while being able to visualize the ultrasound monitor comes first. Identifying the target, mapping the needle trajectory using depth markings, and scanning for nerves, vessels, and other structures that may be damaged along the needle path comes next. Using the in plane ultrasound technique with color Doppler and the nerve contrast setting can ensure that the physician has placed the therapeutic agent to the proper location while avoiding any nerves, arteries, or veins. Marking the borders of the ultrasound probe and needle entry site can be helpful to return to the same area after sterile preparation is done. As in any procedure, sterile technique is paramount. Sterile technique considerations may include using sterile gloves and a probe cover with sterile gel, cleaning the area thoroughly, planning the needle entry point 3 cm to 5 cm away from the probe, and maintaining a dry and gel-free needle entry.^14-15 The probe should be sterilized between patients to avoid cross-contamination; note that certain solutions like alcohol or ethyl chloride can damage the transducer.^14-15 However, simple injections do not require such stringent standards when simple sterile technique is observed by cleaning and then never touching the cleaned area again except with the needle to avoid contamination. Also, ethyl chloride has been found to not contaminate a sterile site and can be used safely to anesthetize the skin.

Ultrasound-Guided Procedures

Many injectable therapeutic options exist as interventions. Cortisone, hyaluronic acid, platelet-rich plasma (PRP), stem cells/bone marrow concentrate (BMC), amniotic fluid, prolotherapy, and saline are now commonly used.^16-17 A meta-analysis of the literature assessing the accuracy of ultrasound-guided shoulder girdle injections vs a landmark-guided injection was done in 2015.¹⁸ It showed that for the acromioclavicular joint, accuracy was 93.6% vs 68.2% (P < .0001), based on single studies. The accuracy of ultrasound vs a landmark-guided injection was 65% vs 70% for the subacromial space (P > .05); 86.7% vs 26.7% for the biceps tendon sheath (P < .05); and 92.5% vs 72.5% for the glenohumeral joint (P = .025).¹⁸ 

With cortisone, injecting into muscle, ligament, or tendons could potentially harm the tissue or cause worsening of the disease process.^19-20 With the advent of orthobiologics, injecting into these structures is now desirable, instead of a potential complication.^19-20 Ultrasound has become even more important to the accurate delivery of these therapies to the disease locations. Multiple studies using leukocyte-poor PRP for osteoarthritis show significant differences in pain scores.^21-23 Peerbooms and colleagues^24,25 also showed that PRP reduced pain and increased function compared to cortisone injections for lateral epicondylitis in 1- and 2-year double-blind randomized controlled trials. Centeno and colleagues²⁶ performed a prospective, multi-site registry study on 102 patients with symptomatic osteoarthritis and/or rotator cuff tears that were injected with bone marrow concentrate. There was a statistically significant improvement in Disabilities of the Arm, Shoulder and Hand (DASH) scores from 36.1 to 17.1 (P < .001) and numeric pain scores improved from 4.3 to 2.4 (P < .001).

By being able to see the pathology, like a hypoechoic region in a tendon, ligament, or muscle, the physician can reliably place the therapeutic agent into the precise location. Also, adjacent para-tendon or para-ligament injections allow for in-season athletes to get some relief from symptoms while allowing to return to play quickly; injections into muscle, ligament, or tendon can damage the structure and require days or weeks of rest, while para-tendon and para-ligament injections are far less painful.

Second-generation techniques have provided patients with great options that can help avoid surgery. Calcific tendonitis appears brightly hyperechoic on ultrasound and is easily identified. The physician can attempt to break up the calcium by fenestration or barbotage of the calcium. The same can be accomplished by injecting the density with PRP or stem cells. If the calcium is soft or “toothpaste-like,” the negative pressure will make it easy to aspirate it into the syringe. A 2-year, longitudinal prospective study of 121 patients demonstrated that visual analog score (VAS) pain scores and size of calcium significantly decreased with ultrasound-guided percutaneous needle lavage; 89% of patients were pain-free at 1-year follow-up.²⁷ Moreover, a randomized controlled trial of 48 patients comparing needle lavage vs subacromial steroid injection showed statistically significant radiographic and clinically better outcomes with the needle lavage group at the 1-year mark.²⁸

The Tenex procedure is a novel technique that uses ultrasonic energy to fenestrate diseased tendon tissue. It also can be used to break up calcific deposits. After the Tenex probe is guided to the diseased tendon/calcium, the TX-1 tip oscillates at the speed of sound, fenestrating/cutting through the tendon or calcium while lavaging the tendon with saline. Multiple prospective, noncontrolled studies done in common extensor, patellar, and rotator cuff tendinopathy have demonstrated good to excellent improvements in pain scores with the Tenex procedure.^29-31

Ultrasound is extremely useful in the treatment of adhesive capsulitis.³² The posterior glenohumeral capsule can be distended using a large volume (60 cc) of saline to loosen adhesions in preparation for manipulation. Because the manipulation can be an extremely painful procedure, ultrasound can be used to perform an inter-scalene block for regional anesthesia prior to the procedure. In 2014, Park and colleagues³³ performed a randomized prospective trial that showed that capsular distension followed by manipulation was more effective than cortisone injection alone for the treatment of adhesive capsulitis.Ultrasound guidance was found to be just as efficacious as fluoroscopy in a randomized controlled trial in 2014; the authors noted that ultrasound does not expose the patient or clinician to radiation and can be done in office.³⁴

Currently, techniques to perform ultrasound-guided percutaneous tenotomies of the long head of the biceps tendon using hook blades are being studied.³⁵

Ultrasound-Assisted Surgery

Ultrasound has been a boon to surgeons who perform minimally invasive procedures. It is far less cumbersome than classic fluoroscopy. Fluoroscopy requires the use of heavy lead aprons by the surgeons. Combining this with the impervious gowns and hot lights, the surgeons’ comfort level is severely sacrificed. When having to do many long surgeries in a row, this situation can take a toll on the surgeons’ endurance and strength. Improving the comfort of the surgeon is not the primary goal of surgery, but can significantly help our ability to do a better job.

Ultrasound allows the surgeon to localize any superficial foreign objects, especially with radiolucent objects like fragments of glass. Small glass fragments or pieces of wood have always been extremely difficult to remove. X-rays cannot localize these objects, so getting a proper orientation is difficult. MRI and CT scans easily identify these types of foreign objects, but cannot be used intraoperatively (Figure 1A). Often, these objects cannot be felt and therefore require a large dissection. The objects may encapsulate and be easily confused with other soft tissues.

Conclusion

Ultrasound is quickly becoming a popular imaging modality due to its simplicity, portability, and cost efficiency. Its use as a diagnostic tool is widely known. As an adjunct for procedures and interventions, its advantages over larger, more expensive modalities such as fluoroscopy, CT, or MRI make it stand out. Ultrasound is not the perfect solution to all problems, but it is clearly a technology that is gaining traction. Ultrasound is another imaging modality and tool that physicians and surgeons can use to improve their patients’ treatment.

Ultrasound has classically been marketed and used as a diagnostic tool. Radiologists, emergency physicians, and sports physicians used ultrasound units to rapidly and appropriately diagnose numerous injuries and disorders, in a timely and cost effective manner. Part 1¹ and Part 2² of this series showed how to use ultrasound in the shoulder for diagnosis and how to code and get reimbursed for its use.Ultrasound can also be used to help guide procedures and interventions performed to treat patients. Currently, more physicians are beginning to recognize the utility of this modality as an aid to interventional procedures.

First-generation procedures use ultrasound to improve accuracy of joint, bursal, tendon, and muscular injections.³ Recent studies have shown a significant improvement in accuracy, outcomes, and patient satisfaction using ultrasound guidance for injections.^3-12 Within the limitation of using a needle, second-generation procedures—hydrodissection of peripherally entrapped nerves, capsular distention, mechanical disruption of neovascularization, and needle fenestration or barbotage in chronic tendinopathy—try to simulate surgical objectives while minimizing tissue burden and other complications of surgery.³ More advanced procedures include needle fenestration/release of the carpal ligament in carpal tunnel syndrome and A1 pulley needle release in the setting of trigger finger.³ Innovative third-generation procedures involve the use of surgical tools such as hook blades under ultrasound guidance to perform surgical procedures. Surgeons are now improving already established percutaneous, arthroscopic, and open surgical procedures with ultrasound assistance.³ Aside from better guidance, reducing cost and improving surgeon comfort may be additional benefits of ultrasound assisted surgery.

Image-Guided Treatment Options

Prior to image guidance, palpation of surface anatomy helped physicians determine the anatomic placement of injections, incisions, or portals. Joints and bursas that do not have any inflammation or fluid can sometimes be difficult to identify or locate by palpation alone. Palpation-guided joint injections often miss their target and cause significant pain when the therapeutic agent is injected into a muscle, tendon, ligament, fat, or other tissue. Ultrasound-guided injections have proven to be more accurate and have better patient satisfaction when compared to blind injections.^3-12

X-ray fluoroscopy has been the primary option for surgeons to assist in surgery. This is a natural modality for orthopedic surgeons; their primary use is for bone to help with fracture reduction and fixation as the bone, instrumentation, and fixation methods are usually radio-opaque. With the advancement in technology, many orthopedic surgeons are regularly using radiolucent fixation devices and working with soft tissue as opposed to bone. Fixation of tendons, ligaments, and muscles would be done using a large incision, palpation of the anatomy, then fixation or repair. Many surgeons began looking for ways to minimize the incisions. Turning to fluoroscopy, a traditional and well-used modality, was a natural progression. Guides and methods were developed to isolate insertions and drill placements. However, fluoroscopy is limited by its difficulty in changing planes and the large equipment required. Also, it is limited in its ability to image soft tissue.

Computed tomography (CT) scans and magnetic resonance imaging (MRI) are far better at imaging soft tissue but cannot be taken for use into the office or surgical suite. These modalities are also far more expensive and take up significant space.

Ultrasound Procedural Basics

Appropriate use of ultrasound still remains highly technician-dependent. Unlike other imaging modalities, ultrasound requires a higher skill level by the physician to implement the use of ultrasound and identification of pathology to treat these disease processes. However, this is no different from the use of arthroscopy or fluoroscopy to treat patients. Training is required, as well as an understanding of the ultrasound machine, anatomy, and sono-anatomy—identification of anatomy and pathology as shown by the ultrasound machine.²

In ultrasound, the long axis refers to looking at a structure along its length, as in longitudinal. The short axis refers to evaluating a structure in cross-section, transverse, or along its shortest length. “In plane” refers to performing a procedure where the needle or object being used enters the ultrasound field along the plane of the transducer, allowing visualization of the majority of the needle as it crosses tissue planes. “Out of plane” has the needle entering perpendicular to the plane of the transducer, showing the needle on the monitor as a bright, hyperechoic dot. Some studies have suggested that novice ultrasonographers should start in a long axis view and use the in plane technique when injecting, as doing so may decrease time to identify the target and improve mean imaging quality during needle advancement.¹³

Anisotropy is the property of being directionally dependent. The ultrasound beam needs to be perpendicular to the structure being imaged to give the optimal image. When the beam hits a longitudinal structure like a needle at an angle <90°, the linear structure might reflect most of the beam away from the transducer. So when using a needle to localize or inject a specific area, maintaining the probe as close to perpendicular as possible with the needle will give a better image. New technology exists to better visualize needles even at high acuity angles by using a multi-beam processing algorithm, which can significantly aid the physician without the need for specialized needles.

Despite better technology, advance planning is key to a successful procedure. Positioning the patient and ultrasound machine in a manner that is comfortable and makes the desired target accessible while being able to visualize the ultrasound monitor comes first. Identifying the target, mapping the needle trajectory using depth markings, and scanning for nerves, vessels, and other structures that may be damaged along the needle path comes next. Using the in plane ultrasound technique with color Doppler and the nerve contrast setting can ensure that the physician has placed the therapeutic agent to the proper location while avoiding any nerves, arteries, or veins. Marking the borders of the ultrasound probe and needle entry site can be helpful to return to the same area after sterile preparation is done. As in any procedure, sterile technique is paramount. Sterile technique considerations may include using sterile gloves and a probe cover with sterile gel, cleaning the area thoroughly, planning the needle entry point 3 cm to 5 cm away from the probe, and maintaining a dry and gel-free needle entry.^14-15 The probe should be sterilized between patients to avoid cross-contamination; note that certain solutions like alcohol or ethyl chloride can damage the transducer.^14-15 However, simple injections do not require such stringent standards when simple sterile technique is observed by cleaning and then never touching the cleaned area again except with the needle to avoid contamination. Also, ethyl chloride has been found to not contaminate a sterile site and can be used safely to anesthetize the skin.

Ultrasound-Guided Procedures

Many injectable therapeutic options exist as interventions. Cortisone, hyaluronic acid, platelet-rich plasma (PRP), stem cells/bone marrow concentrate (BMC), amniotic fluid, prolotherapy, and saline are now commonly used.^16-17 A meta-analysis of the literature assessing the accuracy of ultrasound-guided shoulder girdle injections vs a landmark-guided injection was done in 2015.¹⁸ It showed that for the acromioclavicular joint, accuracy was 93.6% vs 68.2% (P < .0001), based on single studies. The accuracy of ultrasound vs a landmark-guided injection was 65% vs 70% for the subacromial space (P > .05); 86.7% vs 26.7% for the biceps tendon sheath (P < .05); and 92.5% vs 72.5% for the glenohumeral joint (P = .025).¹⁸ 

With cortisone, injecting into muscle, ligament, or tendons could potentially harm the tissue or cause worsening of the disease process.^19-20 With the advent of orthobiologics, injecting into these structures is now desirable, instead of a potential complication.^19-20 Ultrasound has become even more important to the accurate delivery of these therapies to the disease locations. Multiple studies using leukocyte-poor PRP for osteoarthritis show significant differences in pain scores.^21-23 Peerbooms and colleagues^24,25 also showed that PRP reduced pain and increased function compared to cortisone injections for lateral epicondylitis in 1- and 2-year double-blind randomized controlled trials. Centeno and colleagues²⁶ performed a prospective, multi-site registry study on 102 patients with symptomatic osteoarthritis and/or rotator cuff tears that were injected with bone marrow concentrate. There was a statistically significant improvement in Disabilities of the Arm, Shoulder and Hand (DASH) scores from 36.1 to 17.1 (P < .001) and numeric pain scores improved from 4.3 to 2.4 (P < .001).

By being able to see the pathology, like a hypoechoic region in a tendon, ligament, or muscle, the physician can reliably place the therapeutic agent into the precise location. Also, adjacent para-tendon or para-ligament injections allow for in-season athletes to get some relief from symptoms while allowing to return to play quickly; injections into muscle, ligament, or tendon can damage the structure and require days or weeks of rest, while para-tendon and para-ligament injections are far less painful.

Second-generation techniques have provided patients with great options that can help avoid surgery. Calcific tendonitis appears brightly hyperechoic on ultrasound and is easily identified. The physician can attempt to break up the calcium by fenestration or barbotage of the calcium. The same can be accomplished by injecting the density with PRP or stem cells. If the calcium is soft or “toothpaste-like,” the negative pressure will make it easy to aspirate it into the syringe. A 2-year, longitudinal prospective study of 121 patients demonstrated that visual analog score (VAS) pain scores and size of calcium significantly decreased with ultrasound-guided percutaneous needle lavage; 89% of patients were pain-free at 1-year follow-up.²⁷ Moreover, a randomized controlled trial of 48 patients comparing needle lavage vs subacromial steroid injection showed statistically significant radiographic and clinically better outcomes with the needle lavage group at the 1-year mark.²⁸

The Tenex procedure is a novel technique that uses ultrasonic energy to fenestrate diseased tendon tissue. It also can be used to break up calcific deposits. After the Tenex probe is guided to the diseased tendon/calcium, the TX-1 tip oscillates at the speed of sound, fenestrating/cutting through the tendon or calcium while lavaging the tendon with saline. Multiple prospective, noncontrolled studies done in common extensor, patellar, and rotator cuff tendinopathy have demonstrated good to excellent improvements in pain scores with the Tenex procedure.^29-31

Ultrasound is extremely useful in the treatment of adhesive capsulitis.³² The posterior glenohumeral capsule can be distended using a large volume (60 cc) of saline to loosen adhesions in preparation for manipulation. Because the manipulation can be an extremely painful procedure, ultrasound can be used to perform an inter-scalene block for regional anesthesia prior to the procedure. In 2014, Park and colleagues³³ performed a randomized prospective trial that showed that capsular distension followed by manipulation was more effective than cortisone injection alone for the treatment of adhesive capsulitis.Ultrasound guidance was found to be just as efficacious as fluoroscopy in a randomized controlled trial in 2014; the authors noted that ultrasound does not expose the patient or clinician to radiation and can be done in office.³⁴

Currently, techniques to perform ultrasound-guided percutaneous tenotomies of the long head of the biceps tendon using hook blades are being studied.³⁵

Ultrasound-Assisted Surgery

Ultrasound has been a boon to surgeons who perform minimally invasive procedures. It is far less cumbersome than classic fluoroscopy. Fluoroscopy requires the use of heavy lead aprons by the surgeons. Combining this with the impervious gowns and hot lights, the surgeons’ comfort level is severely sacrificed. When having to do many long surgeries in a row, this situation can take a toll on the surgeons’ endurance and strength. Improving the comfort of the surgeon is not the primary goal of surgery, but can significantly help our ability to do a better job.

Ultrasound allows the surgeon to localize any superficial foreign objects, especially with radiolucent objects like fragments of glass. Small glass fragments or pieces of wood have always been extremely difficult to remove. X-rays cannot localize these objects, so getting a proper orientation is difficult. MRI and CT scans easily identify these types of foreign objects, but cannot be used intraoperatively (Figure 1A). Often, these objects cannot be felt and therefore require a large dissection. The objects may encapsulate and be easily confused with other soft tissues.

Conclusion

Ultrasound is quickly becoming a popular imaging modality due to its simplicity, portability, and cost efficiency. Its use as a diagnostic tool is widely known. As an adjunct for procedures and interventions, its advantages over larger, more expensive modalities such as fluoroscopy, CT, or MRI make it stand out. Ultrasound is not the perfect solution to all problems, but it is clearly a technology that is gaining traction. Ultrasound is another imaging modality and tool that physicians and surgeons can use to improve their patients’ treatment.

Ultrasound has classically been marketed and used as a diagnostic tool. Radiologists, emergency physicians, and sports physicians used ultrasound units to rapidly and appropriately diagnose numerous injuries and disorders, in a timely and cost effective manner. Part 1¹ and Part 2² of this series showed how to use ultrasound in the shoulder for diagnosis and how to code and get reimbursed for its use.Ultrasound can also be used to help guide procedures and interventions performed to treat patients. Currently, more physicians are beginning to recognize the utility of this modality as an aid to interventional procedures.

First-generation procedures use ultrasound to improve accuracy of joint, bursal, tendon, and muscular injections.³ Recent studies have shown a significant improvement in accuracy, outcomes, and patient satisfaction using ultrasound guidance for injections.^3-12 Within the limitation of using a needle, second-generation procedures—hydrodissection of peripherally entrapped nerves, capsular distention, mechanical disruption of neovascularization, and needle fenestration or barbotage in chronic tendinopathy—try to simulate surgical objectives while minimizing tissue burden and other complications of surgery.³ More advanced procedures include needle fenestration/release of the carpal ligament in carpal tunnel syndrome and A1 pulley needle release in the setting of trigger finger.³ Innovative third-generation procedures involve the use of surgical tools such as hook blades under ultrasound guidance to perform surgical procedures. Surgeons are now improving already established percutaneous, arthroscopic, and open surgical procedures with ultrasound assistance.³ Aside from better guidance, reducing cost and improving surgeon comfort may be additional benefits of ultrasound assisted surgery.

Image-Guided Treatment Options

Prior to image guidance, palpation of surface anatomy helped physicians determine the anatomic placement of injections, incisions, or portals. Joints and bursas that do not have any inflammation or fluid can sometimes be difficult to identify or locate by palpation alone. Palpation-guided joint injections often miss their target and cause significant pain when the therapeutic agent is injected into a muscle, tendon, ligament, fat, or other tissue. Ultrasound-guided injections have proven to be more accurate and have better patient satisfaction when compared to blind injections.^3-12

X-ray fluoroscopy has been the primary option for surgeons to assist in surgery. This is a natural modality for orthopedic surgeons; their primary use is for bone to help with fracture reduction and fixation as the bone, instrumentation, and fixation methods are usually radio-opaque. With the advancement in technology, many orthopedic surgeons are regularly using radiolucent fixation devices and working with soft tissue as opposed to bone. Fixation of tendons, ligaments, and muscles would be done using a large incision, palpation of the anatomy, then fixation or repair. Many surgeons began looking for ways to minimize the incisions. Turning to fluoroscopy, a traditional and well-used modality, was a natural progression. Guides and methods were developed to isolate insertions and drill placements. However, fluoroscopy is limited by its difficulty in changing planes and the large equipment required. Also, it is limited in its ability to image soft tissue.

Computed tomography (CT) scans and magnetic resonance imaging (MRI) are far better at imaging soft tissue but cannot be taken for use into the office or surgical suite. These modalities are also far more expensive and take up significant space.

Ultrasound Procedural Basics

Appropriate use of ultrasound still remains highly technician-dependent. Unlike other imaging modalities, ultrasound requires a higher skill level by the physician to implement the use of ultrasound and identification of pathology to treat these disease processes. However, this is no different from the use of arthroscopy or fluoroscopy to treat patients. Training is required, as well as an understanding of the ultrasound machine, anatomy, and sono-anatomy—identification of anatomy and pathology as shown by the ultrasound machine.²

In ultrasound, the long axis refers to looking at a structure along its length, as in longitudinal. The short axis refers to evaluating a structure in cross-section, transverse, or along its shortest length. “In plane” refers to performing a procedure where the needle or object being used enters the ultrasound field along the plane of the transducer, allowing visualization of the majority of the needle as it crosses tissue planes. “Out of plane” has the needle entering perpendicular to the plane of the transducer, showing the needle on the monitor as a bright, hyperechoic dot. Some studies have suggested that novice ultrasonographers should start in a long axis view and use the in plane technique when injecting, as doing so may decrease time to identify the target and improve mean imaging quality during needle advancement.¹³

Anisotropy is the property of being directionally dependent. The ultrasound beam needs to be perpendicular to the structure being imaged to give the optimal image. When the beam hits a longitudinal structure like a needle at an angle <90°, the linear structure might reflect most of the beam away from the transducer. So when using a needle to localize or inject a specific area, maintaining the probe as close to perpendicular as possible with the needle will give a better image. New technology exists to better visualize needles even at high acuity angles by using a multi-beam processing algorithm, which can significantly aid the physician without the need for specialized needles.

Despite better technology, advance planning is key to a successful procedure. Positioning the patient and ultrasound machine in a manner that is comfortable and makes the desired target accessible while being able to visualize the ultrasound monitor comes first. Identifying the target, mapping the needle trajectory using depth markings, and scanning for nerves, vessels, and other structures that may be damaged along the needle path comes next. Using the in plane ultrasound technique with color Doppler and the nerve contrast setting can ensure that the physician has placed the therapeutic agent to the proper location while avoiding any nerves, arteries, or veins. Marking the borders of the ultrasound probe and needle entry site can be helpful to return to the same area after sterile preparation is done. As in any procedure, sterile technique is paramount. Sterile technique considerations may include using sterile gloves and a probe cover with sterile gel, cleaning the area thoroughly, planning the needle entry point 3 cm to 5 cm away from the probe, and maintaining a dry and gel-free needle entry.^14-15 The probe should be sterilized between patients to avoid cross-contamination; note that certain solutions like alcohol or ethyl chloride can damage the transducer.^14-15 However, simple injections do not require such stringent standards when simple sterile technique is observed by cleaning and then never touching the cleaned area again except with the needle to avoid contamination. Also, ethyl chloride has been found to not contaminate a sterile site and can be used safely to anesthetize the skin.

Ultrasound-Guided Procedures

Many injectable therapeutic options exist as interventions. Cortisone, hyaluronic acid, platelet-rich plasma (PRP), stem cells/bone marrow concentrate (BMC), amniotic fluid, prolotherapy, and saline are now commonly used.^16-17 A meta-analysis of the literature assessing the accuracy of ultrasound-guided shoulder girdle injections vs a landmark-guided injection was done in 2015.¹⁸ It showed that for the acromioclavicular joint, accuracy was 93.6% vs 68.2% (P < .0001), based on single studies. The accuracy of ultrasound vs a landmark-guided injection was 65% vs 70% for the subacromial space (P > .05); 86.7% vs 26.7% for the biceps tendon sheath (P < .05); and 92.5% vs 72.5% for the glenohumeral joint (P = .025).¹⁸ 

With cortisone, injecting into muscle, ligament, or tendons could potentially harm the tissue or cause worsening of the disease process.^19-20 With the advent of orthobiologics, injecting into these structures is now desirable, instead of a potential complication.^19-20 Ultrasound has become even more important to the accurate delivery of these therapies to the disease locations. Multiple studies using leukocyte-poor PRP for osteoarthritis show significant differences in pain scores.^21-23 Peerbooms and colleagues^24,25 also showed that PRP reduced pain and increased function compared to cortisone injections for lateral epicondylitis in 1- and 2-year double-blind randomized controlled trials. Centeno and colleagues²⁶ performed a prospective, multi-site registry study on 102 patients with symptomatic osteoarthritis and/or rotator cuff tears that were injected with bone marrow concentrate. There was a statistically significant improvement in Disabilities of the Arm, Shoulder and Hand (DASH) scores from 36.1 to 17.1 (P < .001) and numeric pain scores improved from 4.3 to 2.4 (P < .001).

By being able to see the pathology, like a hypoechoic region in a tendon, ligament, or muscle, the physician can reliably place the therapeutic agent into the precise location. Also, adjacent para-tendon or para-ligament injections allow for in-season athletes to get some relief from symptoms while allowing to return to play quickly; injections into muscle, ligament, or tendon can damage the structure and require days or weeks of rest, while para-tendon and para-ligament injections are far less painful.

Second-generation techniques have provided patients with great options that can help avoid surgery. Calcific tendonitis appears brightly hyperechoic on ultrasound and is easily identified. The physician can attempt to break up the calcium by fenestration or barbotage of the calcium. The same can be accomplished by injecting the density with PRP or stem cells. If the calcium is soft or “toothpaste-like,” the negative pressure will make it easy to aspirate it into the syringe. A 2-year, longitudinal prospective study of 121 patients demonstrated that visual analog score (VAS) pain scores and size of calcium significantly decreased with ultrasound-guided percutaneous needle lavage; 89% of patients were pain-free at 1-year follow-up.²⁷ Moreover, a randomized controlled trial of 48 patients comparing needle lavage vs subacromial steroid injection showed statistically significant radiographic and clinically better outcomes with the needle lavage group at the 1-year mark.²⁸

The Tenex procedure is a novel technique that uses ultrasonic energy to fenestrate diseased tendon tissue. It also can be used to break up calcific deposits. After the Tenex probe is guided to the diseased tendon/calcium, the TX-1 tip oscillates at the speed of sound, fenestrating/cutting through the tendon or calcium while lavaging the tendon with saline. Multiple prospective, noncontrolled studies done in common extensor, patellar, and rotator cuff tendinopathy have demonstrated good to excellent improvements in pain scores with the Tenex procedure.^29-31

Ultrasound is extremely useful in the treatment of adhesive capsulitis.³² The posterior glenohumeral capsule can be distended using a large volume (60 cc) of saline to loosen adhesions in preparation for manipulation. Because the manipulation can be an extremely painful procedure, ultrasound can be used to perform an inter-scalene block for regional anesthesia prior to the procedure. In 2014, Park and colleagues³³ performed a randomized prospective trial that showed that capsular distension followed by manipulation was more effective than cortisone injection alone for the treatment of adhesive capsulitis.Ultrasound guidance was found to be just as efficacious as fluoroscopy in a randomized controlled trial in 2014; the authors noted that ultrasound does not expose the patient or clinician to radiation and can be done in office.³⁴

Currently, techniques to perform ultrasound-guided percutaneous tenotomies of the long head of the biceps tendon using hook blades are being studied.³⁵

Ultrasound-Assisted Surgery

Ultrasound has been a boon to surgeons who perform minimally invasive procedures. It is far less cumbersome than classic fluoroscopy. Fluoroscopy requires the use of heavy lead aprons by the surgeons. Combining this with the impervious gowns and hot lights, the surgeons’ comfort level is severely sacrificed. When having to do many long surgeries in a row, this situation can take a toll on the surgeons’ endurance and strength. Improving the comfort of the surgeon is not the primary goal of surgery, but can significantly help our ability to do a better job.

Ultrasound allows the surgeon to localize any superficial foreign objects, especially with radiolucent objects like fragments of glass. Small glass fragments or pieces of wood have always been extremely difficult to remove. X-rays cannot localize these objects, so getting a proper orientation is difficult. MRI and CT scans easily identify these types of foreign objects, but cannot be used intraoperatively (Figure 1A). Often, these objects cannot be felt and therefore require a large dissection. The objects may encapsulate and be easily confused with other soft tissues.

Conclusion

Ultrasound is quickly becoming a popular imaging modality due to its simplicity, portability, and cost efficiency. Its use as a diagnostic tool is widely known. As an adjunct for procedures and interventions, its advantages over larger, more expensive modalities such as fluoroscopy, CT, or MRI make it stand out. Ultrasound is not the perfect solution to all problems, but it is clearly a technology that is gaining traction. Ultrasound is another imaging modality and tool that physicians and surgeons can use to improve their patients’ treatment.