Case Reports

PMP22 is a tetra-span membrane protein primarily expressed in myelinating Schwann cells. Heterozygous deletion of the PMP22 gene (1 copy) causes HNPP (hereditary neuropathy with liability to pressure palsies).¹ Interestingly, a reciprocal genetic disorder with 3 copies of human PMP22 causes the most common inherited neuropathy, Charcot-Marie-Tooth disease type 1A (CMT1A).^2,3 As the reciprocal mutations occur at initiation of gestation, it is expected that HNPP and CMT1A have a similar prevalence. However, studies have shown HNPP prevalence of 2 to 5 cases per 100,000, far below the CMT1A prevalence of 1:5000.⁴ This finding prompted speculation that many patients with HNPP may be undiagnosed because of the subtlety of the phenotypes.⁵

Patients with HNPP typically present with focal sensory loss and muscle weakness related to mechanical stress–induced failure of action potential propagation.^6,7 In this article, we report the case of an asymptomatic woman with the HNPP mutation. Her focal neurologic deficits occurred only after total knee arthroplasty (TKA), which in healthy patients is not expected to induce focal sensory and motor symptoms. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

The patient, a healthy 57-year-old woman, had a normal developmental history. For decades, she had practiced ballet without any physical difficulties. She underwent left TKA and woke up with a footdrop on the left side. The left foot was less sensitive to temperature. Ankle strength returned 2 months later. There was no family history of HNPP.

The patient was examined by a local neurologist, who found steppage gait, weak ankle dorsiflexion (4 on Medical Research Council scale), and diminished touch on the lateral aspect of the left leg. Deep tendon reflexes were present in the arms but not the legs.

A nerve conduction study (NCS) performed after the footdrop revealed prolonged distal latency and decreased amplitude in the left peroneal and tibial nerves. The left sural nerve was normal. Needle electromyogram revealed denervation changes in the muscles innervated by the left peroneal nerve (Table). In addition, we also performed an NCS on the arm (Table), which was unaffected by the surgical procedure. This NCS revealed severely prolonged distal latency across the left wrist in the median nerve and focal slowing of conduction velocity of the ulnar nerve across the left elbow. These changes provide evidence of asymptomatic carpal tunnel syndrome and ulnar nerve entrapment, typical electrophysiologic abnormalities of HNPP.8As there was no explanation for the footdrop from the surgery, we had a DNA test performed (Athena Diagnostics). This test identified a heterozygous deletion of chromosome 17p12 containing the PMP22 gene, the HNPP mutation.

Discussion

This case had several important features. First, though the patient developed an electrophysiologic phenotype of HNPP, she was completely asymptomatic clinically and very athletic before her medical procedure. She would not have been diagnosed with HNPP if her clinical deficits had not been induced by TKA. Therefore, the prevalence of HNPP is likely underestimated. Second, for patients with the HNPP mutation, there may be serious neurologic consequences of certain medical procedures. The diagnosis of HNPP should be pursued if there is no explanation from the medical procedure per se. In addition, patients with a family history of HNPP should be carefully evaluated before any procedure that may put them at risk for severe peripheral nerve damage, and they should be counseled regarding the risks. It is important to determine the prevalence of HNPP among patients who develop footdrop after knee arthroplasty, as this information could potentially be used to revise ideas about the etiology of peripheral nerve complications of knee arthroplasty. We now describe possible revisions of these ideas.

Footdrop is a rare complication of TKA. Retrospective studies have found its incidence ranging from 0.3% to 1.3%.^9-11 The investigators in those studies postulated 3 main causes for peroneal nerve palsy. First, traction may put pressure on the peroneal nerve during normalization of the mechanical axis of a valgus knee. Our patient did not have a valgus knee. Second, epidural hematoma by anesthetic procedure may compress the spinal roots. Our patient received general anesthesia during the procedure; epidural or spinal anesthesia was not used. Third, postoperative dressing may compress the nerve. Our patient did not develop any signs of constrictive dressing, such as inordinate pain, which can be relieved by removing the dressing, and swelling of the leg distal to the dressing. Therefore, her footdrop likely was not a complication of surgery.

This case demonstrates how a patient with undiagnosed HNPP can manifest the HNPP phenotype only after undergoing a particular surgical procedure. HNPP is unfamiliar to most orthopedic surgeons.

PMP22 is a tetra-span membrane protein primarily expressed in myelinating Schwann cells. Heterozygous deletion of the PMP22 gene (1 copy) causes HNPP (hereditary neuropathy with liability to pressure palsies).¹ Interestingly, a reciprocal genetic disorder with 3 copies of human PMP22 causes the most common inherited neuropathy, Charcot-Marie-Tooth disease type 1A (CMT1A).^2,3 As the reciprocal mutations occur at initiation of gestation, it is expected that HNPP and CMT1A have a similar prevalence. However, studies have shown HNPP prevalence of 2 to 5 cases per 100,000, far below the CMT1A prevalence of 1:5000.⁴ This finding prompted speculation that many patients with HNPP may be undiagnosed because of the subtlety of the phenotypes.⁵

Patients with HNPP typically present with focal sensory loss and muscle weakness related to mechanical stress–induced failure of action potential propagation.^6,7 In this article, we report the case of an asymptomatic woman with the HNPP mutation. Her focal neurologic deficits occurred only after total knee arthroplasty (TKA), which in healthy patients is not expected to induce focal sensory and motor symptoms. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

The patient, a healthy 57-year-old woman, had a normal developmental history. For decades, she had practiced ballet without any physical difficulties. She underwent left TKA and woke up with a footdrop on the left side. The left foot was less sensitive to temperature. Ankle strength returned 2 months later. There was no family history of HNPP.

The patient was examined by a local neurologist, who found steppage gait, weak ankle dorsiflexion (4 on Medical Research Council scale), and diminished touch on the lateral aspect of the left leg. Deep tendon reflexes were present in the arms but not the legs.

A nerve conduction study (NCS) performed after the footdrop revealed prolonged distal latency and decreased amplitude in the left peroneal and tibial nerves. The left sural nerve was normal. Needle electromyogram revealed denervation changes in the muscles innervated by the left peroneal nerve (Table). In addition, we also performed an NCS on the arm (Table), which was unaffected by the surgical procedure. This NCS revealed severely prolonged distal latency across the left wrist in the median nerve and focal slowing of conduction velocity of the ulnar nerve across the left elbow. These changes provide evidence of asymptomatic carpal tunnel syndrome and ulnar nerve entrapment, typical electrophysiologic abnormalities of HNPP.8As there was no explanation for the footdrop from the surgery, we had a DNA test performed (Athena Diagnostics). This test identified a heterozygous deletion of chromosome 17p12 containing the PMP22 gene, the HNPP mutation.

Discussion

This case had several important features. First, though the patient developed an electrophysiologic phenotype of HNPP, she was completely asymptomatic clinically and very athletic before her medical procedure. She would not have been diagnosed with HNPP if her clinical deficits had not been induced by TKA. Therefore, the prevalence of HNPP is likely underestimated. Second, for patients with the HNPP mutation, there may be serious neurologic consequences of certain medical procedures. The diagnosis of HNPP should be pursued if there is no explanation from the medical procedure per se. In addition, patients with a family history of HNPP should be carefully evaluated before any procedure that may put them at risk for severe peripheral nerve damage, and they should be counseled regarding the risks. It is important to determine the prevalence of HNPP among patients who develop footdrop after knee arthroplasty, as this information could potentially be used to revise ideas about the etiology of peripheral nerve complications of knee arthroplasty. We now describe possible revisions of these ideas.

Footdrop is a rare complication of TKA. Retrospective studies have found its incidence ranging from 0.3% to 1.3%.^9-11 The investigators in those studies postulated 3 main causes for peroneal nerve palsy. First, traction may put pressure on the peroneal nerve during normalization of the mechanical axis of a valgus knee. Our patient did not have a valgus knee. Second, epidural hematoma by anesthetic procedure may compress the spinal roots. Our patient received general anesthesia during the procedure; epidural or spinal anesthesia was not used. Third, postoperative dressing may compress the nerve. Our patient did not develop any signs of constrictive dressing, such as inordinate pain, which can be relieved by removing the dressing, and swelling of the leg distal to the dressing. Therefore, her footdrop likely was not a complication of surgery.

This case demonstrates how a patient with undiagnosed HNPP can manifest the HNPP phenotype only after undergoing a particular surgical procedure. HNPP is unfamiliar to most orthopedic surgeons.

PMP22 is a tetra-span membrane protein primarily expressed in myelinating Schwann cells. Heterozygous deletion of the PMP22 gene (1 copy) causes HNPP (hereditary neuropathy with liability to pressure palsies).¹ Interestingly, a reciprocal genetic disorder with 3 copies of human PMP22 causes the most common inherited neuropathy, Charcot-Marie-Tooth disease type 1A (CMT1A).^2,3 As the reciprocal mutations occur at initiation of gestation, it is expected that HNPP and CMT1A have a similar prevalence. However, studies have shown HNPP prevalence of 2 to 5 cases per 100,000, far below the CMT1A prevalence of 1:5000.⁴ This finding prompted speculation that many patients with HNPP may be undiagnosed because of the subtlety of the phenotypes.⁵

Patients with HNPP typically present with focal sensory loss and muscle weakness related to mechanical stress–induced failure of action potential propagation.^6,7 In this article, we report the case of an asymptomatic woman with the HNPP mutation. Her focal neurologic deficits occurred only after total knee arthroplasty (TKA), which in healthy patients is not expected to induce focal sensory and motor symptoms. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

The patient, a healthy 57-year-old woman, had a normal developmental history. For decades, she had practiced ballet without any physical difficulties. She underwent left TKA and woke up with a footdrop on the left side. The left foot was less sensitive to temperature. Ankle strength returned 2 months later. There was no family history of HNPP.

The patient was examined by a local neurologist, who found steppage gait, weak ankle dorsiflexion (4 on Medical Research Council scale), and diminished touch on the lateral aspect of the left leg. Deep tendon reflexes were present in the arms but not the legs.

A nerve conduction study (NCS) performed after the footdrop revealed prolonged distal latency and decreased amplitude in the left peroneal and tibial nerves. The left sural nerve was normal. Needle electromyogram revealed denervation changes in the muscles innervated by the left peroneal nerve (Table). In addition, we also performed an NCS on the arm (Table), which was unaffected by the surgical procedure. This NCS revealed severely prolonged distal latency across the left wrist in the median nerve and focal slowing of conduction velocity of the ulnar nerve across the left elbow. These changes provide evidence of asymptomatic carpal tunnel syndrome and ulnar nerve entrapment, typical electrophysiologic abnormalities of HNPP.8As there was no explanation for the footdrop from the surgery, we had a DNA test performed (Athena Diagnostics). This test identified a heterozygous deletion of chromosome 17p12 containing the PMP22 gene, the HNPP mutation.

Discussion

This case had several important features. First, though the patient developed an electrophysiologic phenotype of HNPP, she was completely asymptomatic clinically and very athletic before her medical procedure. She would not have been diagnosed with HNPP if her clinical deficits had not been induced by TKA. Therefore, the prevalence of HNPP is likely underestimated. Second, for patients with the HNPP mutation, there may be serious neurologic consequences of certain medical procedures. The diagnosis of HNPP should be pursued if there is no explanation from the medical procedure per se. In addition, patients with a family history of HNPP should be carefully evaluated before any procedure that may put them at risk for severe peripheral nerve damage, and they should be counseled regarding the risks. It is important to determine the prevalence of HNPP among patients who develop footdrop after knee arthroplasty, as this information could potentially be used to revise ideas about the etiology of peripheral nerve complications of knee arthroplasty. We now describe possible revisions of these ideas.

Footdrop is a rare complication of TKA. Retrospective studies have found its incidence ranging from 0.3% to 1.3%.^9-11 The investigators in those studies postulated 3 main causes for peroneal nerve palsy. First, traction may put pressure on the peroneal nerve during normalization of the mechanical axis of a valgus knee. Our patient did not have a valgus knee. Second, epidural hematoma by anesthetic procedure may compress the spinal roots. Our patient received general anesthesia during the procedure; epidural or spinal anesthesia was not used. Third, postoperative dressing may compress the nerve. Our patient did not develop any signs of constrictive dressing, such as inordinate pain, which can be relieved by removing the dressing, and swelling of the leg distal to the dressing. Therefore, her footdrop likely was not a complication of surgery.

This case demonstrates how a patient with undiagnosed HNPP can manifest the HNPP phenotype only after undergoing a particular surgical procedure. HNPP is unfamiliar to most orthopedic surgeons.

Tibial tubercle fractures are rare injuries accounting for less than 1% of all pediatric physeal injuries.¹ The original classification scheme for such fractures was proposed by Watson-Jones.² Initially modified by Ogden and colleagues,³ the classification system has had numerous additions and modifications as new patterns of injury have been identified.^4-6 Patellar fractures are also rare in children, making up 1% of all pediatric fractures, with less than 2% of these occurring in skeletally immature children.⁷

We present a case of an unreported combined tibial tubercle avulsion fracture and patellar avulsion fracture in an adolescent boy. The patient and his guardian provided written informed consent for print and electronic publication of this case report.

Case Report

A 12-year-old boy presented to the emergency department with acute onset of right-knee pain and inability to ambulate after falling off a skateboard on the day of the injury. The patient was otherwise healthy and had no noteworthy medical or surgical history, including no prior fractures. On physical examination, he was noted to have a large right-knee effusion presumed to be hemarthrosis, and inability to perform a straight-leg raise against gravity. There were no neurologic deficits and his leg compartments were soft. Plain radiographs showed patella alta and numerous bony fragments believed to represent a complex tibial tubercle fracture. One bony fragment was identified closer to the patella, suggesting a possible concurrent patellar fracture (Figures 1A, 1B). A computed tomography (CT) scan further characterized both the tibial tubercle avulsion fracture and the lateral inferior pole patellar avulsion fracture (Figures 2A, 2B). The patient’s knee was immobilized, and he was admitted for soft-tissue rest and overnight observation to ensure that compartment syndrome did not develop.

 

Five days after injury, open reduction and internal fixation were performed. After limb exsanguination and tourniquet insufflation, the fracture was visualized through a direct midline approach. The patient was found to have a Z-type injury pattern to the extensor mechanism: an inferior lateral patellar avulsion fracture, longitudinal splits of the patellar tendon, and 2 large, mainly cartilaginous tibial tubercle fracture fragments, 1 of which extended into the proximal tibial epiphysis (Ogden type III) (Figures 3A-3C). Under direct visualization, the tibial tubercle fragments were reduced and stabilized with 3 cannulated 3.5-mm titanium, partially threaded screws with washers. Smaller screws were used to prevent fragmentation of these mostly cartilaginous fragments. Anatomic reduction was ensured along the articular surface, visualized through an arthrotomy, as well as on the distal cortex (Figures 4A, 4B). The patellar avulsion fracture included a very small section of articular surface and the decision was made to preserve the fragment. Because the patellar fragment was too small for screw fixation, the fracture was secured with suture fixation through bone tunnels over a patellar bony bridge using size 2 Phantom Fiber suture (Tornier) (Figure 5). Vicryl was used to repair the longitudinal patellar tendon split as well as the capsular and paratenon traumatic tears. Layered closure was completed and intraoperative radiographs were obtained (Figures 6A, 6B) prior to placement of a cylinder cast in full extension. Postoperatively, the patient remained overnight for observation and physical therapy evaluation. He was encouraged to bear weight in his cylinder cast as tolerated with crutches to assist with ambulation.

 

Postoperatively, the patient was maintained in full extension in the cylinder cast for 4 weeks. After cast removal, the patient was placed in a range-of-motion brace locked in extension for ambulation. He started physical therapy and was allowed to perform prone active-knee flexion limited to 90º, with passive extension, for an additional 4 weeks. At 8 weeks, the patient was allowed full-knee motion both active and passive, and the brace was discontinued. At his 18-week follow-up appointment, the patient reported successful return to all his normal activities, including skateboarding, with no apparent limitation in motion or weight-bearing. Examination at that time demonstrated knee range of motion from 5º in hyperextension to 135º in flexion, with his left knee having 5º in hyperextension and 145º in flexion. The patient appeared to have no gait abnormalities, and radiographs showed healed fractures. Because of a concern that continued compression across his tibial physis could lead to greater risk of growth arrest, the decision was made to remove the implants when radiographs showed healing. The patient returned to surgery at 20 weeks for implant removal. At 6 weeks after implant removal, the patient had returned to full activity with no residual pain and full-knee flexion equal to the uninvolved left knee. He was able to perform a stable single-leg squat on his affected leg, and his single-leg hop for distance was the same as his uninvolved leg. He was allowed to return to full sports activity. The patient will be followed with serial radiographs at 4 months, 8 months, and 12 months to look for premature physeal arrest. If an arrest occurs, treatment will be dictated by the extent of the arrest and the potential to cause either limb-length difference or angular deformity.

 

Discussion

Tibial tubercle fractures typically result from quadriceps contraction during sporting activities, predominantly in adolescent boys with open physes. Numerous modifications and additions have been made to the original classification of such fractures by Watson-Jones,² most notably by Ogden and colleagues³ in 1980. These additions have included combined tendon avulsions and tubercle fractures as described by Frankl and coauthors,⁴ complete proximal tibial physeal separation now classified as type 4 by Ryu and Debenham,⁵ and a “Y” fracture configuration now termed type 5 by McKoy and Stanitski.⁶ Pandya and colleagues⁸ reported on 41 tibial tubercle fractures and described a new classification scheme based on the known anatomical closure pattern of the proximal tibial physis and tibial tubercle apophysis. The authors stressed the role of advanced imaging, such as CT or magnetic resonance imaging, in preoperative management of these complex high-energy fractures in adolescents, and the need for intraoperative arthroscopy or arthrotomy to ensure anatomical reduction of the articular involvement.

Tibial tubercle fractures and extensor mechanism injuries that do not fit these classification patterns have also been described. In 1979, Houghton and Ackroyd⁹ reported 3 cases of acute loss of extensor mechanism secondary to a traumatic patellar sleeve avulsion. In 1995, Berg¹⁰ described an ipsilateral inferior pole osteochondral patellar avulsion fracture with patellar tendon avulsion without fracture at the tubercle in a 12-year-old boy. Another variant was described in a 2002 case series of 3 adolescent boys who underwent operative fixation for tibial metaphyseal partial-sleeve avulsion injuries.¹¹

Conclusion

We report a case of combined ipsilateral inferior lateral patellar avulsion fracture and an intra-articular tibial tubercle avulsion fracture with intervening longitudinal patellar tendon split. Preoperative standard radiographs were confusing, given the bony fragment high up by the patella, but use of advanced imaging, in this case CT, allowed us to fully characterize the origin of fracture fragments and realize we were dealing with a unique fracture pattern previously unreported in a pediatric patient. The CT findings allowed us to be better prepared preoperatively by having options for fixation of the patellar fracture, and the extent of articular involvement led us to decide that intra-articular evaluation would be required. Through the use of an open arthrotomy, anatomical articular reduction could be visualized and stabilized with screw fixation of the large, mostly cartilaginous tubercle fracture. Following the principles described by Pandya and colleagues,8 anatomical reduction was achieved, and, 6 months after the original surgery, the patient had return of full motion, clinical and radiographic union, and no clinical pain or limp, with no retained metallic implants across the tibial apophysis. Longer-term follow-up as planned will demonstrate any growth abnormality that would require further surgical intervention.

Tibial tubercle fractures are rare injuries accounting for less than 1% of all pediatric physeal injuries.¹ The original classification scheme for such fractures was proposed by Watson-Jones.² Initially modified by Ogden and colleagues,³ the classification system has had numerous additions and modifications as new patterns of injury have been identified.^4-6 Patellar fractures are also rare in children, making up 1% of all pediatric fractures, with less than 2% of these occurring in skeletally immature children.⁷

We present a case of an unreported combined tibial tubercle avulsion fracture and patellar avulsion fracture in an adolescent boy. The patient and his guardian provided written informed consent for print and electronic publication of this case report.

Case Report

A 12-year-old boy presented to the emergency department with acute onset of right-knee pain and inability to ambulate after falling off a skateboard on the day of the injury. The patient was otherwise healthy and had no noteworthy medical or surgical history, including no prior fractures. On physical examination, he was noted to have a large right-knee effusion presumed to be hemarthrosis, and inability to perform a straight-leg raise against gravity. There were no neurologic deficits and his leg compartments were soft. Plain radiographs showed patella alta and numerous bony fragments believed to represent a complex tibial tubercle fracture. One bony fragment was identified closer to the patella, suggesting a possible concurrent patellar fracture (Figures 1A, 1B). A computed tomography (CT) scan further characterized both the tibial tubercle avulsion fracture and the lateral inferior pole patellar avulsion fracture (Figures 2A, 2B). The patient’s knee was immobilized, and he was admitted for soft-tissue rest and overnight observation to ensure that compartment syndrome did not develop.

 

Five days after injury, open reduction and internal fixation were performed. After limb exsanguination and tourniquet insufflation, the fracture was visualized through a direct midline approach. The patient was found to have a Z-type injury pattern to the extensor mechanism: an inferior lateral patellar avulsion fracture, longitudinal splits of the patellar tendon, and 2 large, mainly cartilaginous tibial tubercle fracture fragments, 1 of which extended into the proximal tibial epiphysis (Ogden type III) (Figures 3A-3C). Under direct visualization, the tibial tubercle fragments were reduced and stabilized with 3 cannulated 3.5-mm titanium, partially threaded screws with washers. Smaller screws were used to prevent fragmentation of these mostly cartilaginous fragments. Anatomic reduction was ensured along the articular surface, visualized through an arthrotomy, as well as on the distal cortex (Figures 4A, 4B). The patellar avulsion fracture included a very small section of articular surface and the decision was made to preserve the fragment. Because the patellar fragment was too small for screw fixation, the fracture was secured with suture fixation through bone tunnels over a patellar bony bridge using size 2 Phantom Fiber suture (Tornier) (Figure 5). Vicryl was used to repair the longitudinal patellar tendon split as well as the capsular and paratenon traumatic tears. Layered closure was completed and intraoperative radiographs were obtained (Figures 6A, 6B) prior to placement of a cylinder cast in full extension. Postoperatively, the patient remained overnight for observation and physical therapy evaluation. He was encouraged to bear weight in his cylinder cast as tolerated with crutches to assist with ambulation.

 

Postoperatively, the patient was maintained in full extension in the cylinder cast for 4 weeks. After cast removal, the patient was placed in a range-of-motion brace locked in extension for ambulation. He started physical therapy and was allowed to perform prone active-knee flexion limited to 90º, with passive extension, for an additional 4 weeks. At 8 weeks, the patient was allowed full-knee motion both active and passive, and the brace was discontinued. At his 18-week follow-up appointment, the patient reported successful return to all his normal activities, including skateboarding, with no apparent limitation in motion or weight-bearing. Examination at that time demonstrated knee range of motion from 5º in hyperextension to 135º in flexion, with his left knee having 5º in hyperextension and 145º in flexion. The patient appeared to have no gait abnormalities, and radiographs showed healed fractures. Because of a concern that continued compression across his tibial physis could lead to greater risk of growth arrest, the decision was made to remove the implants when radiographs showed healing. The patient returned to surgery at 20 weeks for implant removal. At 6 weeks after implant removal, the patient had returned to full activity with no residual pain and full-knee flexion equal to the uninvolved left knee. He was able to perform a stable single-leg squat on his affected leg, and his single-leg hop for distance was the same as his uninvolved leg. He was allowed to return to full sports activity. The patient will be followed with serial radiographs at 4 months, 8 months, and 12 months to look for premature physeal arrest. If an arrest occurs, treatment will be dictated by the extent of the arrest and the potential to cause either limb-length difference or angular deformity.

 

Discussion

Tibial tubercle fractures typically result from quadriceps contraction during sporting activities, predominantly in adolescent boys with open physes. Numerous modifications and additions have been made to the original classification of such fractures by Watson-Jones,² most notably by Ogden and colleagues³ in 1980. These additions have included combined tendon avulsions and tubercle fractures as described by Frankl and coauthors,⁴ complete proximal tibial physeal separation now classified as type 4 by Ryu and Debenham,⁵ and a “Y” fracture configuration now termed type 5 by McKoy and Stanitski.⁶ Pandya and colleagues⁸ reported on 41 tibial tubercle fractures and described a new classification scheme based on the known anatomical closure pattern of the proximal tibial physis and tibial tubercle apophysis. The authors stressed the role of advanced imaging, such as CT or magnetic resonance imaging, in preoperative management of these complex high-energy fractures in adolescents, and the need for intraoperative arthroscopy or arthrotomy to ensure anatomical reduction of the articular involvement.

Tibial tubercle fractures and extensor mechanism injuries that do not fit these classification patterns have also been described. In 1979, Houghton and Ackroyd⁹ reported 3 cases of acute loss of extensor mechanism secondary to a traumatic patellar sleeve avulsion. In 1995, Berg¹⁰ described an ipsilateral inferior pole osteochondral patellar avulsion fracture with patellar tendon avulsion without fracture at the tubercle in a 12-year-old boy. Another variant was described in a 2002 case series of 3 adolescent boys who underwent operative fixation for tibial metaphyseal partial-sleeve avulsion injuries.¹¹

Conclusion

We report a case of combined ipsilateral inferior lateral patellar avulsion fracture and an intra-articular tibial tubercle avulsion fracture with intervening longitudinal patellar tendon split. Preoperative standard radiographs were confusing, given the bony fragment high up by the patella, but use of advanced imaging, in this case CT, allowed us to fully characterize the origin of fracture fragments and realize we were dealing with a unique fracture pattern previously unreported in a pediatric patient. The CT findings allowed us to be better prepared preoperatively by having options for fixation of the patellar fracture, and the extent of articular involvement led us to decide that intra-articular evaluation would be required. Through the use of an open arthrotomy, anatomical articular reduction could be visualized and stabilized with screw fixation of the large, mostly cartilaginous tubercle fracture. Following the principles described by Pandya and colleagues,8 anatomical reduction was achieved, and, 6 months after the original surgery, the patient had return of full motion, clinical and radiographic union, and no clinical pain or limp, with no retained metallic implants across the tibial apophysis. Longer-term follow-up as planned will demonstrate any growth abnormality that would require further surgical intervention.

Tibial tubercle fractures are rare injuries accounting for less than 1% of all pediatric physeal injuries.¹ The original classification scheme for such fractures was proposed by Watson-Jones.² Initially modified by Ogden and colleagues,³ the classification system has had numerous additions and modifications as new patterns of injury have been identified.^4-6 Patellar fractures are also rare in children, making up 1% of all pediatric fractures, with less than 2% of these occurring in skeletally immature children.⁷

We present a case of an unreported combined tibial tubercle avulsion fracture and patellar avulsion fracture in an adolescent boy. The patient and his guardian provided written informed consent for print and electronic publication of this case report.

Case Report

A 12-year-old boy presented to the emergency department with acute onset of right-knee pain and inability to ambulate after falling off a skateboard on the day of the injury. The patient was otherwise healthy and had no noteworthy medical or surgical history, including no prior fractures. On physical examination, he was noted to have a large right-knee effusion presumed to be hemarthrosis, and inability to perform a straight-leg raise against gravity. There were no neurologic deficits and his leg compartments were soft. Plain radiographs showed patella alta and numerous bony fragments believed to represent a complex tibial tubercle fracture. One bony fragment was identified closer to the patella, suggesting a possible concurrent patellar fracture (Figures 1A, 1B). A computed tomography (CT) scan further characterized both the tibial tubercle avulsion fracture and the lateral inferior pole patellar avulsion fracture (Figures 2A, 2B). The patient’s knee was immobilized, and he was admitted for soft-tissue rest and overnight observation to ensure that compartment syndrome did not develop.

 

Five days after injury, open reduction and internal fixation were performed. After limb exsanguination and tourniquet insufflation, the fracture was visualized through a direct midline approach. The patient was found to have a Z-type injury pattern to the extensor mechanism: an inferior lateral patellar avulsion fracture, longitudinal splits of the patellar tendon, and 2 large, mainly cartilaginous tibial tubercle fracture fragments, 1 of which extended into the proximal tibial epiphysis (Ogden type III) (Figures 3A-3C). Under direct visualization, the tibial tubercle fragments were reduced and stabilized with 3 cannulated 3.5-mm titanium, partially threaded screws with washers. Smaller screws were used to prevent fragmentation of these mostly cartilaginous fragments. Anatomic reduction was ensured along the articular surface, visualized through an arthrotomy, as well as on the distal cortex (Figures 4A, 4B). The patellar avulsion fracture included a very small section of articular surface and the decision was made to preserve the fragment. Because the patellar fragment was too small for screw fixation, the fracture was secured with suture fixation through bone tunnels over a patellar bony bridge using size 2 Phantom Fiber suture (Tornier) (Figure 5). Vicryl was used to repair the longitudinal patellar tendon split as well as the capsular and paratenon traumatic tears. Layered closure was completed and intraoperative radiographs were obtained (Figures 6A, 6B) prior to placement of a cylinder cast in full extension. Postoperatively, the patient remained overnight for observation and physical therapy evaluation. He was encouraged to bear weight in his cylinder cast as tolerated with crutches to assist with ambulation.

 

Postoperatively, the patient was maintained in full extension in the cylinder cast for 4 weeks. After cast removal, the patient was placed in a range-of-motion brace locked in extension for ambulation. He started physical therapy and was allowed to perform prone active-knee flexion limited to 90º, with passive extension, for an additional 4 weeks. At 8 weeks, the patient was allowed full-knee motion both active and passive, and the brace was discontinued. At his 18-week follow-up appointment, the patient reported successful return to all his normal activities, including skateboarding, with no apparent limitation in motion or weight-bearing. Examination at that time demonstrated knee range of motion from 5º in hyperextension to 135º in flexion, with his left knee having 5º in hyperextension and 145º in flexion. The patient appeared to have no gait abnormalities, and radiographs showed healed fractures. Because of a concern that continued compression across his tibial physis could lead to greater risk of growth arrest, the decision was made to remove the implants when radiographs showed healing. The patient returned to surgery at 20 weeks for implant removal. At 6 weeks after implant removal, the patient had returned to full activity with no residual pain and full-knee flexion equal to the uninvolved left knee. He was able to perform a stable single-leg squat on his affected leg, and his single-leg hop for distance was the same as his uninvolved leg. He was allowed to return to full sports activity. The patient will be followed with serial radiographs at 4 months, 8 months, and 12 months to look for premature physeal arrest. If an arrest occurs, treatment will be dictated by the extent of the arrest and the potential to cause either limb-length difference or angular deformity.

 

Discussion

Tibial tubercle fractures typically result from quadriceps contraction during sporting activities, predominantly in adolescent boys with open physes. Numerous modifications and additions have been made to the original classification of such fractures by Watson-Jones,² most notably by Ogden and colleagues³ in 1980. These additions have included combined tendon avulsions and tubercle fractures as described by Frankl and coauthors,⁴ complete proximal tibial physeal separation now classified as type 4 by Ryu and Debenham,⁵ and a “Y” fracture configuration now termed type 5 by McKoy and Stanitski.⁶ Pandya and colleagues⁸ reported on 41 tibial tubercle fractures and described a new classification scheme based on the known anatomical closure pattern of the proximal tibial physis and tibial tubercle apophysis. The authors stressed the role of advanced imaging, such as CT or magnetic resonance imaging, in preoperative management of these complex high-energy fractures in adolescents, and the need for intraoperative arthroscopy or arthrotomy to ensure anatomical reduction of the articular involvement.

Tibial tubercle fractures and extensor mechanism injuries that do not fit these classification patterns have also been described. In 1979, Houghton and Ackroyd⁹ reported 3 cases of acute loss of extensor mechanism secondary to a traumatic patellar sleeve avulsion. In 1995, Berg¹⁰ described an ipsilateral inferior pole osteochondral patellar avulsion fracture with patellar tendon avulsion without fracture at the tubercle in a 12-year-old boy. Another variant was described in a 2002 case series of 3 adolescent boys who underwent operative fixation for tibial metaphyseal partial-sleeve avulsion injuries.¹¹

Conclusion

We report a case of combined ipsilateral inferior lateral patellar avulsion fracture and an intra-articular tibial tubercle avulsion fracture with intervening longitudinal patellar tendon split. Preoperative standard radiographs were confusing, given the bony fragment high up by the patella, but use of advanced imaging, in this case CT, allowed us to fully characterize the origin of fracture fragments and realize we were dealing with a unique fracture pattern previously unreported in a pediatric patient. The CT findings allowed us to be better prepared preoperatively by having options for fixation of the patellar fracture, and the extent of articular involvement led us to decide that intra-articular evaluation would be required. Through the use of an open arthrotomy, anatomical articular reduction could be visualized and stabilized with screw fixation of the large, mostly cartilaginous tubercle fracture. Following the principles described by Pandya and colleagues,8 anatomical reduction was achieved, and, 6 months after the original surgery, the patient had return of full motion, clinical and radiographic union, and no clinical pain or limp, with no retained metallic implants across the tibial apophysis. Longer-term follow-up as planned will demonstrate any growth abnormality that would require further surgical intervention.

Case

A 76-year-old woman presented to the ED with right rib pain after tripping on a rug and sustaining a fall down the stairs in her home. The patient’s chart review showed a history of multiple falls over the past year, with injuries including left rib fracture, right distal radius fracture, ankle sprain, forehead contusion, and left hip contusion. Regarding her social history, the patient denied any alcohol or drug use. She was not on any prescription medications and had no known medication or food allergies.

The physical examination was notable for a thin, white female in no apparent distress. The patient’s vital signs at presentation were: temperature, 97.2°F; blood pressure, 110/78 mm Hg; heart rate, 110 beats/minute; respiratory rate, 24 breaths/minute. She was somnolent but arousable and oriented to person, place, and time. The right chest wall was tender, and her lungs were clear to auscultation. The cardiac and neurological examinations were within normal limits. The patient had multiple contusions of various stages of healing over all extremities.

  

Introduction

Geriatric patients aged 65 years and older represent a large, growing segment of the US population and, according to US Census Bureau data, represent an estimated 14% of the  population.¹ Moreover, this population accounts for 36% of all ambulance transports, 25% of hospitalizations, and 25% of total trauma costs.² Although geriatric patients are less likely to be involved in trauma compared with other age groups, they are more likely to have fatal outcomes when injured. Approximately 28% of deaths due to accidental causes involve persons aged 65 and older. The highest mortality rates from trauma are noted in patients in the 8th decade and older.³

  

Mechanism of Injury and Preexisting Conditions

Falls are the most common mechanism of injury in patients over age 65 years,⁴ and mortality as a result of falls increases with advanced age.⁵ In addition to the increased risk of trauma, comorbid diseases are also common in this population and include diabetes mellitus, coronary artery disease, arthritis, renal disease, and pulmonary disease.⁶

The presence of preexisting conditions, which affect a patient’s physiological age, is associated with increased mortality rates.^7,8 As with other age groups, outcomes for geriatric trauma patients can also be predicted using the Injury Severity Score.⁹ Conditions associated with altered mental status in the geriatric trauma population and are listed in Table 1.

  

Review Data

Geriatric trauma patients frequently present with altered mental status. An understanding of potential etiologies of altered mental status is important to the ED diagnosis and management.

The issue of traumatic injury in the aging population was studied at the authors’ institution through a retrospective chart review at the ED of Miami Valley Hospital, Dayton, Ohio, an urban hospital with an annual patient census of 95,000 visits.¹⁰ This study was approved by the Wright State University Institutional Review Board (IRB) and the Miami Valley Hospital Human Investigation and Research Committee (HIRC).

The study included 1,077 geriatric trauma patients, 144 of whom had a Glasgow Coma Score (GCS) of 14 or lower (13.4%). Fifty-four percent of the patients were male. Most (88.19%) of the patients were white, 9.72 % were black, 0.69% were Hispanic, and 1.39% were of other ethnicities. The median patient age was 78.5±7.81 (SD). Forty-two percent of patients were transferred to Miami Valley Hospital from another institution. The mode of arrival and mechanism of injury are outlined in Table 2. The most common mode of arrival was ambulance (n = 101), followed by helicopter (n = 38), and walk-in (n = 5). Fall (n = 106) and motor vehicle collision (n = 26) were the most common mechanisms of injury. The most common comorbid medical conditions were hypertension (56%) and heart disease (49%; Table 3).

Laboratory Findings

Hyperglycemia (n = 121) was the most common laboratory abnormality seen in patients, followed by anemia (n = 71), sodium abnormalities (n = 13), and hypoglycemia (n = 4). The most common finding on brain computed tomography (CT) was subdural hemorrhage (n = 55; Table 4). The results of both alcohol and urine toxicology screens are outlined in Table 5. In this study, 82 patients were not tested for alcohol intoxication, and 109 patients did not have a urine toxicology screen. Of the patients tested for alcohol intoxication, 20% had an alcohol level greater than 80 mg/mL (legal limit for operating a motor vehicle in the state of Ohio). There was no significant association between alcohol level and age, gender (Fisher’s exact test, P=.49), or ethnicity (Fisher’s exact test, P=.08). Opiates were the most commonly found substance in patients tested via a urine toxicology screen.

 

Mortality

Although traumatic injury is a common presentation among geriatric emergency patients, this population is overall less likely to be involved in a traumatic event compared to other age groups. However, when injured, geriatric trauma patients are more likely to have fatal outcomes.

As previously noted, falls are the most common mechanism of injury in patients older than age 65 years. The trend of fall-related mortality increases with advanced age. It has been estimated that 36% of geriatric patients who fall will require a repeat ED visit or will die within 1 year following the fall.¹¹ Previous reports have demonstrated that mortality is associated with advanced age, injury severity score, shock index, transfusion, head injury, hypotension, and treatment site.^12-16

Cerebral Hemorrhage

In the study conducted at the authors’ institution, most patients receiving a head CT scan had at least one abnormality.¹⁰ Subdural hemorrhage was the most commonly reported abnormality followed by subarachnoid and intraparenchymal hemorrhages, respectively.¹⁰

Falls are a common cause of intracranial hemorrhage, and 30% to 40% of patients over age 65 years will experience at least one fall each year.¹⁷ Consistent with these statistics, fall was the most common mechanism of injury in the patient population at the authors’ institution. Intracranial hemorrhage can cause altered mental status by increasing the intracranial pressure and decreasing the cerebral perfusion pressure. These abnormalities are often amenable to medical and/or surgical treatment if identified in time.¹⁸

Hyperglycemia

Hyperglycemia was one of the most common diagnostic test abnormalities associated with altered mental status in the authors' study.¹⁰ Although increased blood glucose is part of the stress response to injury, geriatric patients experience a higher incidence of stress hyperglycemia and are unable to mount an adequate insulin response in trauma.^19,20 High-glucose levels are associated with significantly higher mortality rates among trauma patients.^21-24

Alcohol Intoxication

Alcohol intoxication was common among the patients in the author’s study.¹⁰ In contrast, a smaller percentage of patients were tested and found to be positive for opioids or benzodiazepines. The risk of a traumatic brain injury (TBI) increases significantly if the patient sustained the injury while under the influence of alcohol.²⁵ Alcohol increases the mortality after trauma especially in patients over the age of 40.²⁶ Alcohol-related TBIs are associated with poorer outcomes with increasing age.²⁷ Falls at ground level after alcohol consumption are associated with more casualties than nonalcohol-related falls.^28,29

  

Differential Diagnosis

As the case in this review illustrates, among geriatric trauma patients with altered mental status, the most common mechanism of injury is fall. The differential diagnosis should be considered, including intracranial hemorrhage, alcohol intoxication, nonprescription drug use, prescription-drug effects, infection, and/or metabolic or endocrine disorders. Appropriate laboratory and radiographic tests should be obtained, and may include CT of the brain and cervical spine, chemistry profile, complete blood count, chest X-ray, urinalysis, alcohol level, and toxicology screen.

  

Conclusion

This case represents one of many common presentations of trauma among geriatric patients. There was evidence of multiple falls by chart review and physical examination. Evidence of multiple traumatic events of various stages should raise the suspicion of neurological deficits, substance or prescription-medication effects, or physical abuse of the elderly patient. The ED workup should include brain CT, electrolytes, complete blood count, chest radiograph, and urinalysis. The patient should be admitted for observation and workup for medical and traumatic etiologies of multiple falls. When discharged, home-health services or rehabilitation services should be considered.

The results of the authors’ chart-review study confirmed that falls are the most common mechanism of injury in geriatric trauma patients presenting to the ED with altered mental status.¹⁰ The most common diagnostic test abnormalities associated with altered mental status in this study included hyperglycemia, abnormal CT results, anemia, and alcohol intoxication. Future studies are needed to access relations between ethanol or opioid intoxication and the presence of positive CT findings to guide clinicians’ judgment when ordering CT scans and other tests.

  

---

Dr Marco is a professor of emergency medicine and surgery, Wright State University Boonshoft School of Medicine, Kettering, Ohio; and an emergency physician at Miami Valley Hospital, Dayton, Ohio. Ms Edgell, Ms Eggers, and Mr Fagan are students at Wright State University Boonshoft School of Medicine, Dayton, Ohio. Dr Olson is the director of the research laboratory and professor of emergency medicine at Wright State University Boonshoft School of Medicine, Kettering, Ohio.

Case

A 76-year-old woman presented to the ED with right rib pain after tripping on a rug and sustaining a fall down the stairs in her home. The patient’s chart review showed a history of multiple falls over the past year, with injuries including left rib fracture, right distal radius fracture, ankle sprain, forehead contusion, and left hip contusion. Regarding her social history, the patient denied any alcohol or drug use. She was not on any prescription medications and had no known medication or food allergies.

The physical examination was notable for a thin, white female in no apparent distress. The patient’s vital signs at presentation were: temperature, 97.2°F; blood pressure, 110/78 mm Hg; heart rate, 110 beats/minute; respiratory rate, 24 breaths/minute. She was somnolent but arousable and oriented to person, place, and time. The right chest wall was tender, and her lungs were clear to auscultation. The cardiac and neurological examinations were within normal limits. The patient had multiple contusions of various stages of healing over all extremities.

  

Introduction

Geriatric patients aged 65 years and older represent a large, growing segment of the US population and, according to US Census Bureau data, represent an estimated 14% of the  population.¹ Moreover, this population accounts for 36% of all ambulance transports, 25% of hospitalizations, and 25% of total trauma costs.² Although geriatric patients are less likely to be involved in trauma compared with other age groups, they are more likely to have fatal outcomes when injured. Approximately 28% of deaths due to accidental causes involve persons aged 65 and older. The highest mortality rates from trauma are noted in patients in the 8th decade and older.³

  

Mechanism of Injury and Preexisting Conditions

Falls are the most common mechanism of injury in patients over age 65 years,⁴ and mortality as a result of falls increases with advanced age.⁵ In addition to the increased risk of trauma, comorbid diseases are also common in this population and include diabetes mellitus, coronary artery disease, arthritis, renal disease, and pulmonary disease.⁶

The presence of preexisting conditions, which affect a patient’s physiological age, is associated with increased mortality rates.^7,8 As with other age groups, outcomes for geriatric trauma patients can also be predicted using the Injury Severity Score.⁹ Conditions associated with altered mental status in the geriatric trauma population and are listed in Table 1.

  

Review Data

Geriatric trauma patients frequently present with altered mental status. An understanding of potential etiologies of altered mental status is important to the ED diagnosis and management.

The issue of traumatic injury in the aging population was studied at the authors’ institution through a retrospective chart review at the ED of Miami Valley Hospital, Dayton, Ohio, an urban hospital with an annual patient census of 95,000 visits.¹⁰ This study was approved by the Wright State University Institutional Review Board (IRB) and the Miami Valley Hospital Human Investigation and Research Committee (HIRC).

The study included 1,077 geriatric trauma patients, 144 of whom had a Glasgow Coma Score (GCS) of 14 or lower (13.4%). Fifty-four percent of the patients were male. Most (88.19%) of the patients were white, 9.72 % were black, 0.69% were Hispanic, and 1.39% were of other ethnicities. The median patient age was 78.5±7.81 (SD). Forty-two percent of patients were transferred to Miami Valley Hospital from another institution. The mode of arrival and mechanism of injury are outlined in Table 2. The most common mode of arrival was ambulance (n = 101), followed by helicopter (n = 38), and walk-in (n = 5). Fall (n = 106) and motor vehicle collision (n = 26) were the most common mechanisms of injury. The most common comorbid medical conditions were hypertension (56%) and heart disease (49%; Table 3).

Laboratory Findings

Hyperglycemia (n = 121) was the most common laboratory abnormality seen in patients, followed by anemia (n = 71), sodium abnormalities (n = 13), and hypoglycemia (n = 4). The most common finding on brain computed tomography (CT) was subdural hemorrhage (n = 55; Table 4). The results of both alcohol and urine toxicology screens are outlined in Table 5. In this study, 82 patients were not tested for alcohol intoxication, and 109 patients did not have a urine toxicology screen. Of the patients tested for alcohol intoxication, 20% had an alcohol level greater than 80 mg/mL (legal limit for operating a motor vehicle in the state of Ohio). There was no significant association between alcohol level and age, gender (Fisher’s exact test, P=.49), or ethnicity (Fisher’s exact test, P=.08). Opiates were the most commonly found substance in patients tested via a urine toxicology screen.

 

Mortality

Although traumatic injury is a common presentation among geriatric emergency patients, this population is overall less likely to be involved in a traumatic event compared to other age groups. However, when injured, geriatric trauma patients are more likely to have fatal outcomes.

As previously noted, falls are the most common mechanism of injury in patients older than age 65 years. The trend of fall-related mortality increases with advanced age. It has been estimated that 36% of geriatric patients who fall will require a repeat ED visit or will die within 1 year following the fall.¹¹ Previous reports have demonstrated that mortality is associated with advanced age, injury severity score, shock index, transfusion, head injury, hypotension, and treatment site.^12-16

Cerebral Hemorrhage

In the study conducted at the authors’ institution, most patients receiving a head CT scan had at least one abnormality.¹⁰ Subdural hemorrhage was the most commonly reported abnormality followed by subarachnoid and intraparenchymal hemorrhages, respectively.¹⁰

Falls are a common cause of intracranial hemorrhage, and 30% to 40% of patients over age 65 years will experience at least one fall each year.¹⁷ Consistent with these statistics, fall was the most common mechanism of injury in the patient population at the authors’ institution. Intracranial hemorrhage can cause altered mental status by increasing the intracranial pressure and decreasing the cerebral perfusion pressure. These abnormalities are often amenable to medical and/or surgical treatment if identified in time.¹⁸

Hyperglycemia

Hyperglycemia was one of the most common diagnostic test abnormalities associated with altered mental status in the authors' study.¹⁰ Although increased blood glucose is part of the stress response to injury, geriatric patients experience a higher incidence of stress hyperglycemia and are unable to mount an adequate insulin response in trauma.^19,20 High-glucose levels are associated with significantly higher mortality rates among trauma patients.^21-24

Alcohol Intoxication

Alcohol intoxication was common among the patients in the author’s study.¹⁰ In contrast, a smaller percentage of patients were tested and found to be positive for opioids or benzodiazepines. The risk of a traumatic brain injury (TBI) increases significantly if the patient sustained the injury while under the influence of alcohol.²⁵ Alcohol increases the mortality after trauma especially in patients over the age of 40.²⁶ Alcohol-related TBIs are associated with poorer outcomes with increasing age.²⁷ Falls at ground level after alcohol consumption are associated with more casualties than nonalcohol-related falls.^28,29

  

Differential Diagnosis

As the case in this review illustrates, among geriatric trauma patients with altered mental status, the most common mechanism of injury is fall. The differential diagnosis should be considered, including intracranial hemorrhage, alcohol intoxication, nonprescription drug use, prescription-drug effects, infection, and/or metabolic or endocrine disorders. Appropriate laboratory and radiographic tests should be obtained, and may include CT of the brain and cervical spine, chemistry profile, complete blood count, chest X-ray, urinalysis, alcohol level, and toxicology screen.

  

Conclusion

This case represents one of many common presentations of trauma among geriatric patients. There was evidence of multiple falls by chart review and physical examination. Evidence of multiple traumatic events of various stages should raise the suspicion of neurological deficits, substance or prescription-medication effects, or physical abuse of the elderly patient. The ED workup should include brain CT, electrolytes, complete blood count, chest radiograph, and urinalysis. The patient should be admitted for observation and workup for medical and traumatic etiologies of multiple falls. When discharged, home-health services or rehabilitation services should be considered.

The results of the authors’ chart-review study confirmed that falls are the most common mechanism of injury in geriatric trauma patients presenting to the ED with altered mental status.¹⁰ The most common diagnostic test abnormalities associated with altered mental status in this study included hyperglycemia, abnormal CT results, anemia, and alcohol intoxication. Future studies are needed to access relations between ethanol or opioid intoxication and the presence of positive CT findings to guide clinicians’ judgment when ordering CT scans and other tests.

  

---

Dr Marco is a professor of emergency medicine and surgery, Wright State University Boonshoft School of Medicine, Kettering, Ohio; and an emergency physician at Miami Valley Hospital, Dayton, Ohio. Ms Edgell, Ms Eggers, and Mr Fagan are students at Wright State University Boonshoft School of Medicine, Dayton, Ohio. Dr Olson is the director of the research laboratory and professor of emergency medicine at Wright State University Boonshoft School of Medicine, Kettering, Ohio.

Case

A 76-year-old woman presented to the ED with right rib pain after tripping on a rug and sustaining a fall down the stairs in her home. The patient’s chart review showed a history of multiple falls over the past year, with injuries including left rib fracture, right distal radius fracture, ankle sprain, forehead contusion, and left hip contusion. Regarding her social history, the patient denied any alcohol or drug use. She was not on any prescription medications and had no known medication or food allergies.

The physical examination was notable for a thin, white female in no apparent distress. The patient’s vital signs at presentation were: temperature, 97.2°F; blood pressure, 110/78 mm Hg; heart rate, 110 beats/minute; respiratory rate, 24 breaths/minute. She was somnolent but arousable and oriented to person, place, and time. The right chest wall was tender, and her lungs were clear to auscultation. The cardiac and neurological examinations were within normal limits. The patient had multiple contusions of various stages of healing over all extremities.

  

Introduction

Geriatric patients aged 65 years and older represent a large, growing segment of the US population and, according to US Census Bureau data, represent an estimated 14% of the  population.¹ Moreover, this population accounts for 36% of all ambulance transports, 25% of hospitalizations, and 25% of total trauma costs.² Although geriatric patients are less likely to be involved in trauma compared with other age groups, they are more likely to have fatal outcomes when injured. Approximately 28% of deaths due to accidental causes involve persons aged 65 and older. The highest mortality rates from trauma are noted in patients in the 8th decade and older.³

  

Mechanism of Injury and Preexisting Conditions

Falls are the most common mechanism of injury in patients over age 65 years,⁴ and mortality as a result of falls increases with advanced age.⁵ In addition to the increased risk of trauma, comorbid diseases are also common in this population and include diabetes mellitus, coronary artery disease, arthritis, renal disease, and pulmonary disease.⁶

The presence of preexisting conditions, which affect a patient’s physiological age, is associated with increased mortality rates.^7,8 As with other age groups, outcomes for geriatric trauma patients can also be predicted using the Injury Severity Score.⁹ Conditions associated with altered mental status in the geriatric trauma population and are listed in Table 1.

  

Review Data

Geriatric trauma patients frequently present with altered mental status. An understanding of potential etiologies of altered mental status is important to the ED diagnosis and management.

The issue of traumatic injury in the aging population was studied at the authors’ institution through a retrospective chart review at the ED of Miami Valley Hospital, Dayton, Ohio, an urban hospital with an annual patient census of 95,000 visits.¹⁰ This study was approved by the Wright State University Institutional Review Board (IRB) and the Miami Valley Hospital Human Investigation and Research Committee (HIRC).

The study included 1,077 geriatric trauma patients, 144 of whom had a Glasgow Coma Score (GCS) of 14 or lower (13.4%). Fifty-four percent of the patients were male. Most (88.19%) of the patients were white, 9.72 % were black, 0.69% were Hispanic, and 1.39% were of other ethnicities. The median patient age was 78.5±7.81 (SD). Forty-two percent of patients were transferred to Miami Valley Hospital from another institution. The mode of arrival and mechanism of injury are outlined in Table 2. The most common mode of arrival was ambulance (n = 101), followed by helicopter (n = 38), and walk-in (n = 5). Fall (n = 106) and motor vehicle collision (n = 26) were the most common mechanisms of injury. The most common comorbid medical conditions were hypertension (56%) and heart disease (49%; Table 3).

Laboratory Findings

Hyperglycemia (n = 121) was the most common laboratory abnormality seen in patients, followed by anemia (n = 71), sodium abnormalities (n = 13), and hypoglycemia (n = 4). The most common finding on brain computed tomography (CT) was subdural hemorrhage (n = 55; Table 4). The results of both alcohol and urine toxicology screens are outlined in Table 5. In this study, 82 patients were not tested for alcohol intoxication, and 109 patients did not have a urine toxicology screen. Of the patients tested for alcohol intoxication, 20% had an alcohol level greater than 80 mg/mL (legal limit for operating a motor vehicle in the state of Ohio). There was no significant association between alcohol level and age, gender (Fisher’s exact test, P=.49), or ethnicity (Fisher’s exact test, P=.08). Opiates were the most commonly found substance in patients tested via a urine toxicology screen.

 

Mortality

Although traumatic injury is a common presentation among geriatric emergency patients, this population is overall less likely to be involved in a traumatic event compared to other age groups. However, when injured, geriatric trauma patients are more likely to have fatal outcomes.

As previously noted, falls are the most common mechanism of injury in patients older than age 65 years. The trend of fall-related mortality increases with advanced age. It has been estimated that 36% of geriatric patients who fall will require a repeat ED visit or will die within 1 year following the fall.¹¹ Previous reports have demonstrated that mortality is associated with advanced age, injury severity score, shock index, transfusion, head injury, hypotension, and treatment site.^12-16

Cerebral Hemorrhage

In the study conducted at the authors’ institution, most patients receiving a head CT scan had at least one abnormality.¹⁰ Subdural hemorrhage was the most commonly reported abnormality followed by subarachnoid and intraparenchymal hemorrhages, respectively.¹⁰

Falls are a common cause of intracranial hemorrhage, and 30% to 40% of patients over age 65 years will experience at least one fall each year.¹⁷ Consistent with these statistics, fall was the most common mechanism of injury in the patient population at the authors’ institution. Intracranial hemorrhage can cause altered mental status by increasing the intracranial pressure and decreasing the cerebral perfusion pressure. These abnormalities are often amenable to medical and/or surgical treatment if identified in time.¹⁸

Hyperglycemia

Hyperglycemia was one of the most common diagnostic test abnormalities associated with altered mental status in the authors' study.¹⁰ Although increased blood glucose is part of the stress response to injury, geriatric patients experience a higher incidence of stress hyperglycemia and are unable to mount an adequate insulin response in trauma.^19,20 High-glucose levels are associated with significantly higher mortality rates among trauma patients.^21-24

Alcohol Intoxication

Alcohol intoxication was common among the patients in the author’s study.¹⁰ In contrast, a smaller percentage of patients were tested and found to be positive for opioids or benzodiazepines. The risk of a traumatic brain injury (TBI) increases significantly if the patient sustained the injury while under the influence of alcohol.²⁵ Alcohol increases the mortality after trauma especially in patients over the age of 40.²⁶ Alcohol-related TBIs are associated with poorer outcomes with increasing age.²⁷ Falls at ground level after alcohol consumption are associated with more casualties than nonalcohol-related falls.^28,29

  

Differential Diagnosis

As the case in this review illustrates, among geriatric trauma patients with altered mental status, the most common mechanism of injury is fall. The differential diagnosis should be considered, including intracranial hemorrhage, alcohol intoxication, nonprescription drug use, prescription-drug effects, infection, and/or metabolic or endocrine disorders. Appropriate laboratory and radiographic tests should be obtained, and may include CT of the brain and cervical spine, chemistry profile, complete blood count, chest X-ray, urinalysis, alcohol level, and toxicology screen.

  

Conclusion

This case represents one of many common presentations of trauma among geriatric patients. There was evidence of multiple falls by chart review and physical examination. Evidence of multiple traumatic events of various stages should raise the suspicion of neurological deficits, substance or prescription-medication effects, or physical abuse of the elderly patient. The ED workup should include brain CT, electrolytes, complete blood count, chest radiograph, and urinalysis. The patient should be admitted for observation and workup for medical and traumatic etiologies of multiple falls. When discharged, home-health services or rehabilitation services should be considered.

The results of the authors’ chart-review study confirmed that falls are the most common mechanism of injury in geriatric trauma patients presenting to the ED with altered mental status.¹⁰ The most common diagnostic test abnormalities associated with altered mental status in this study included hyperglycemia, abnormal CT results, anemia, and alcohol intoxication. Future studies are needed to access relations between ethanol or opioid intoxication and the presence of positive CT findings to guide clinicians’ judgment when ordering CT scans and other tests.

  

---

Dr Marco is a professor of emergency medicine and surgery, Wright State University Boonshoft School of Medicine, Kettering, Ohio; and an emergency physician at Miami Valley Hospital, Dayton, Ohio. Ms Edgell, Ms Eggers, and Mr Fagan are students at Wright State University Boonshoft School of Medicine, Dayton, Ohio. Dr Olson is the director of the research laboratory and professor of emergency medicine at Wright State University Boonshoft School of Medicine, Kettering, Ohio.

Case

The mother of a 3-year-old boy presented her son to the ED for evaluation after she noticed peeling of the skin in his perianal region. She stated that the peeling had started 1 day prior to presentation. Two days earlier, the mother had brought the same patient to the ED for evaluation of a fever, sore throat, and a slight rash over his face. The boy’s vital signs at the initial presentation were: temperature, 101.8°F; heart rate, 102 beats/minute; and respiratory rate, 28 breaths/minute. Oxygen saturation was 98% on room air.

During this first visit, the mother denied the child having had any fever, chills, headache, sore throat, facial rash, joint pain, or pain on defecation. He had no significant medical history and no known drug allergies. After examination, a throat culture was taken, and the patient was given acetaminophen and discharged home with a diagnosis of viral syndrome.

At the second presentation, physical examination revealed a well-developed child in no distress. The examination was negative except for a 4 x 2 cm area of desquamation present over the perianal region (Figure).

The area of desquamation was dry, mildly erythematous without discharge, and nontender. The patient’s vital signs at this presentation were stable, and he was afebrile. The remaining physical examination findings were normal. The throat culture taken during the first ED presentation was reported as negative. A perianal swab was sent for culture and sensitivity. This was later reported to be positive for group A β-hemolytic streptococci (GABHS), which is sensitive to penicillin. The patient was discharged home in the care of his mother with a prescription of penicillin.  A 10-day follow-up showed complete resolution of the skin rash.

  

Discussion

Perianal streptococcal dermatitis (PSD), which is caused by GABHS, is a frequently overlooked medical entity. Landolt et al¹ investigated the prevalence of PSD at the University Children’s Hospital Basel, Switzerland, from October 2000 to May 2001. In this study, 250 randomly selected patients were studied for signs of PSD by history, examination, and culture, the results of which showed that PSD was frequent in the study cohort. The study further underscored that, to appropriately treat affected patients, signs and symptoms of PSD should be searched for systematically.¹

The rash in this case was most likely the result of scarlet fever with an unusual presentation of PSD; the signs and symptoms of which include perianal erythema, itching, rectal pain, sometimes blood-streaked stools, rectal bleeding, irritation or pruritus, tissue loss and exudation, secondary constipation, and cellulitis. Perianal streptococcal dermatitis has also been described in the adult literature.² As with pediatric cases, PSD in adults is usually caused by GABHS.

Evaluation and Diagnosis

A rapid streptococcal test of suspicious areas can confirm the diagnosis. Fever, sore throat, and arthralgia are rare; however, culture from the perianal region grows GABHS. Titers are usually not elevated in laboratory evaluation. A routine skin culture is an alternative diagnostic aid.

Brilliant² described the bright red color of PSD as a sharply demarcated rash that is caused by GABHS. As previously stated, symptoms include perianal rash, itching, and rectal pain; blood-streaked stools may also be seen in one-third of patients. It primarily occurs in children between 6 months and 10 years of age and is often misdiagnosed and treated inappropriately.³

Prompt diagnosis of GABHS is important. If untreated, it can cause serious systemic infections, especially in elderly and in newborn patients. Treatment with antibiotics resolves the condition in the majority of patients.² In the acute stage, a white pseudomembrane may be present. As the rash becomes more chronic, the perianal eruption may consist of painful fissures, a dry mucoid discharge, or psoriasiform plaques. Perianal dermatitis can also be caused by Staphylococcus aureus or Candida. Confirmation of the diagnosis is accomplished by culturing a moderate-to-heavy growth of GABHS on 5% sheep-blood agar.

Treatment

A 10-day course of oral penicillin produces resolution of the dermatitis and other symptoms in most patients, but a relapse rate as high as 39% has been reported. Other treatment plans include amoxicillin, 40 mg/kg per day, divided into three doses, and/or topical applications of mupirocin 2% three times per day for 10 days. Penicillin, clindamycin phosphate, and erythromycin have also been used.

Although penicillin is generally recommended for treatment of GABHS infection, amoxicillin is often better tolerated in the pediatric population due to its superior palatability. Early antibiotic treatment causes a dramatic and rapid improvement of symptoms. However, according to Olson et al,⁴ PSD initially treated with amoxicillin or penicillin is consistently associated with a high risk of clinical recurrence. Whether treatment with a β-lactamase–resistant agent reduces this risk is uncertain.

 

  

Conclusion

This case represents an unusual presentation of scarlet fever manifesting as perianal dermatitis caused by GABHS. Although more common in the pediatric population, adult cases have been documented in the literature. As this case illustrates, early recognition and treatment with penicillin (or amoxicillin) produces rapid improvement and resolution of symptoms. 

  

---

Dr Nibhanipudi is a professor of clinical emergency medicine at New York Medical College - Metropolitan Hospital Center, New York.

Case

The mother of a 3-year-old boy presented her son to the ED for evaluation after she noticed peeling of the skin in his perianal region. She stated that the peeling had started 1 day prior to presentation. Two days earlier, the mother had brought the same patient to the ED for evaluation of a fever, sore throat, and a slight rash over his face. The boy’s vital signs at the initial presentation were: temperature, 101.8°F; heart rate, 102 beats/minute; and respiratory rate, 28 breaths/minute. Oxygen saturation was 98% on room air.

During this first visit, the mother denied the child having had any fever, chills, headache, sore throat, facial rash, joint pain, or pain on defecation. He had no significant medical history and no known drug allergies. After examination, a throat culture was taken, and the patient was given acetaminophen and discharged home with a diagnosis of viral syndrome.

At the second presentation, physical examination revealed a well-developed child in no distress. The examination was negative except for a 4 x 2 cm area of desquamation present over the perianal region (Figure).

The area of desquamation was dry, mildly erythematous without discharge, and nontender. The patient’s vital signs at this presentation were stable, and he was afebrile. The remaining physical examination findings were normal. The throat culture taken during the first ED presentation was reported as negative. A perianal swab was sent for culture and sensitivity. This was later reported to be positive for group A β-hemolytic streptococci (GABHS), which is sensitive to penicillin. The patient was discharged home in the care of his mother with a prescription of penicillin.  A 10-day follow-up showed complete resolution of the skin rash.

  

Discussion

Perianal streptococcal dermatitis (PSD), which is caused by GABHS, is a frequently overlooked medical entity. Landolt et al¹ investigated the prevalence of PSD at the University Children’s Hospital Basel, Switzerland, from October 2000 to May 2001. In this study, 250 randomly selected patients were studied for signs of PSD by history, examination, and culture, the results of which showed that PSD was frequent in the study cohort. The study further underscored that, to appropriately treat affected patients, signs and symptoms of PSD should be searched for systematically.¹

The rash in this case was most likely the result of scarlet fever with an unusual presentation of PSD; the signs and symptoms of which include perianal erythema, itching, rectal pain, sometimes blood-streaked stools, rectal bleeding, irritation or pruritus, tissue loss and exudation, secondary constipation, and cellulitis. Perianal streptococcal dermatitis has also been described in the adult literature.² As with pediatric cases, PSD in adults is usually caused by GABHS.

Evaluation and Diagnosis

A rapid streptococcal test of suspicious areas can confirm the diagnosis. Fever, sore throat, and arthralgia are rare; however, culture from the perianal region grows GABHS. Titers are usually not elevated in laboratory evaluation. A routine skin culture is an alternative diagnostic aid.

Brilliant² described the bright red color of PSD as a sharply demarcated rash that is caused by GABHS. As previously stated, symptoms include perianal rash, itching, and rectal pain; blood-streaked stools may also be seen in one-third of patients. It primarily occurs in children between 6 months and 10 years of age and is often misdiagnosed and treated inappropriately.³

Prompt diagnosis of GABHS is important. If untreated, it can cause serious systemic infections, especially in elderly and in newborn patients. Treatment with antibiotics resolves the condition in the majority of patients.² In the acute stage, a white pseudomembrane may be present. As the rash becomes more chronic, the perianal eruption may consist of painful fissures, a dry mucoid discharge, or psoriasiform plaques. Perianal dermatitis can also be caused by Staphylococcus aureus or Candida. Confirmation of the diagnosis is accomplished by culturing a moderate-to-heavy growth of GABHS on 5% sheep-blood agar.

Treatment

A 10-day course of oral penicillin produces resolution of the dermatitis and other symptoms in most patients, but a relapse rate as high as 39% has been reported. Other treatment plans include amoxicillin, 40 mg/kg per day, divided into three doses, and/or topical applications of mupirocin 2% three times per day for 10 days. Penicillin, clindamycin phosphate, and erythromycin have also been used.

Although penicillin is generally recommended for treatment of GABHS infection, amoxicillin is often better tolerated in the pediatric population due to its superior palatability. Early antibiotic treatment causes a dramatic and rapid improvement of symptoms. However, according to Olson et al,⁴ PSD initially treated with amoxicillin or penicillin is consistently associated with a high risk of clinical recurrence. Whether treatment with a β-lactamase–resistant agent reduces this risk is uncertain.

 

  

Conclusion

This case represents an unusual presentation of scarlet fever manifesting as perianal dermatitis caused by GABHS. Although more common in the pediatric population, adult cases have been documented in the literature. As this case illustrates, early recognition and treatment with penicillin (or amoxicillin) produces rapid improvement and resolution of symptoms. 

  

---

Dr Nibhanipudi is a professor of clinical emergency medicine at New York Medical College - Metropolitan Hospital Center, New York.

Case

The mother of a 3-year-old boy presented her son to the ED for evaluation after she noticed peeling of the skin in his perianal region. She stated that the peeling had started 1 day prior to presentation. Two days earlier, the mother had brought the same patient to the ED for evaluation of a fever, sore throat, and a slight rash over his face. The boy’s vital signs at the initial presentation were: temperature, 101.8°F; heart rate, 102 beats/minute; and respiratory rate, 28 breaths/minute. Oxygen saturation was 98% on room air.

During this first visit, the mother denied the child having had any fever, chills, headache, sore throat, facial rash, joint pain, or pain on defecation. He had no significant medical history and no known drug allergies. After examination, a throat culture was taken, and the patient was given acetaminophen and discharged home with a diagnosis of viral syndrome.

At the second presentation, physical examination revealed a well-developed child in no distress. The examination was negative except for a 4 x 2 cm area of desquamation present over the perianal region (Figure).

The area of desquamation was dry, mildly erythematous without discharge, and nontender. The patient’s vital signs at this presentation were stable, and he was afebrile. The remaining physical examination findings were normal. The throat culture taken during the first ED presentation was reported as negative. A perianal swab was sent for culture and sensitivity. This was later reported to be positive for group A β-hemolytic streptococci (GABHS), which is sensitive to penicillin. The patient was discharged home in the care of his mother with a prescription of penicillin.  A 10-day follow-up showed complete resolution of the skin rash.

  

Discussion

Perianal streptococcal dermatitis (PSD), which is caused by GABHS, is a frequently overlooked medical entity. Landolt et al¹ investigated the prevalence of PSD at the University Children’s Hospital Basel, Switzerland, from October 2000 to May 2001. In this study, 250 randomly selected patients were studied for signs of PSD by history, examination, and culture, the results of which showed that PSD was frequent in the study cohort. The study further underscored that, to appropriately treat affected patients, signs and symptoms of PSD should be searched for systematically.¹

The rash in this case was most likely the result of scarlet fever with an unusual presentation of PSD; the signs and symptoms of which include perianal erythema, itching, rectal pain, sometimes blood-streaked stools, rectal bleeding, irritation or pruritus, tissue loss and exudation, secondary constipation, and cellulitis. Perianal streptococcal dermatitis has also been described in the adult literature.² As with pediatric cases, PSD in adults is usually caused by GABHS.

Evaluation and Diagnosis

A rapid streptococcal test of suspicious areas can confirm the diagnosis. Fever, sore throat, and arthralgia are rare; however, culture from the perianal region grows GABHS. Titers are usually not elevated in laboratory evaluation. A routine skin culture is an alternative diagnostic aid.

Brilliant² described the bright red color of PSD as a sharply demarcated rash that is caused by GABHS. As previously stated, symptoms include perianal rash, itching, and rectal pain; blood-streaked stools may also be seen in one-third of patients. It primarily occurs in children between 6 months and 10 years of age and is often misdiagnosed and treated inappropriately.³

Prompt diagnosis of GABHS is important. If untreated, it can cause serious systemic infections, especially in elderly and in newborn patients. Treatment with antibiotics resolves the condition in the majority of patients.² In the acute stage, a white pseudomembrane may be present. As the rash becomes more chronic, the perianal eruption may consist of painful fissures, a dry mucoid discharge, or psoriasiform plaques. Perianal dermatitis can also be caused by Staphylococcus aureus or Candida. Confirmation of the diagnosis is accomplished by culturing a moderate-to-heavy growth of GABHS on 5% sheep-blood agar.

Treatment

A 10-day course of oral penicillin produces resolution of the dermatitis and other symptoms in most patients, but a relapse rate as high as 39% has been reported. Other treatment plans include amoxicillin, 40 mg/kg per day, divided into three doses, and/or topical applications of mupirocin 2% three times per day for 10 days. Penicillin, clindamycin phosphate, and erythromycin have also been used.

Although penicillin is generally recommended for treatment of GABHS infection, amoxicillin is often better tolerated in the pediatric population due to its superior palatability. Early antibiotic treatment causes a dramatic and rapid improvement of symptoms. However, according to Olson et al,⁴ PSD initially treated with amoxicillin or penicillin is consistently associated with a high risk of clinical recurrence. Whether treatment with a β-lactamase–resistant agent reduces this risk is uncertain.

 

  

Conclusion

This case represents an unusual presentation of scarlet fever manifesting as perianal dermatitis caused by GABHS. Although more common in the pediatric population, adult cases have been documented in the literature. As this case illustrates, early recognition and treatment with penicillin (or amoxicillin) produces rapid improvement and resolution of symptoms. 

  

---

Dr Nibhanipudi is a professor of clinical emergency medicine at New York Medical College - Metropolitan Hospital Center, New York.

 A bone island is a focus of normal cortical bone located within the medullary cavity. The vast majority of bone islands are small, measuring from 1 mm to 2 cm in size. They are found more frequently in adults than in children. The lesion can be virtually diagnosed on the basis of its characteristic clinical and imaging features. Differential diagnosis may be difficult when the lesion manifests itself uncharacteristically by being symptomatic, very large, and hot on bone scan.^1-4

The term giant bone island has been used to describe a large lesion1 that measures more than 2 cm in any dimension.⁵ Giant bone islands have been described only in adults,^1,5-15 and the longest bone island length reported is 10.5 cm.¹⁰ They are usually symptomatic and associated with increased radionuclide uptake on bone scintigraphy.¹⁴

The history and the clinical and imaging presentation of an even longer, symptomatic, and scintigraphically hot lesion in the tibial diaphysis of a 10-year-old boy is reported. The lesion further exhibited several atypical imaging features necessitating an open biopsy, which confirmed the diagnosis of a giant bone island. The pertinent differential diagnosis and the clinical and radiographic findings after 15-year follow-up are also presented and discussed. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 10-year-old boy was admitted for surgical repair of an inguinal hernia. Physical examination revealed a painless but tender anterior bowing of the right tibial diaphysis. The patient was a healthy-appearing white male with normal vital signs, gait, and posture. His parents noticed a slight protuberance of the tibia at age 2.5 years. No medical advice was asked for the bone swelling after that time. After recovery from the inguinal hernia repair 3 weeks later, the bone lesion was thoroughly examined. Radiographs showed an oblong, homogenous region of dense sclerosis in the diaphysis of the right tibia. The lesion had relatively well-defined margins and was located in the medullary cavity. Speculations were not obvious in the periphery of the lesion, which exhibited a sharp circumscription (Figures 1A, 1B). A well-defined lytic area was evident at the distal part of the lesion (Figure 1B). There was no periosteal reaction. Blood and serum chemistries were within normal limits, including serum calcium, phosphorus, and alkaline phosphatase. A conventional 3-phase bone scintigraphy (300 MBq) with technetium-99m HDP (hydroxydiphosphonate) indicated increased uptake in the area of the lesion but no other skeletal abnormality (Figure 2). Computed tomography (CT) showed that the lesion was purely intramedullary and densely blastic. The lesion originated from the medial cortex, which was thickened (Figure 3A). The lesion extended to the anterolateral cortex, which was thinned and included a lytic area. In the distal part of the lesion, the anterolateral cortex was thickened, included lytic areas, and exhibited an anterior portion of cortical destruction (Figure 3B). The fatty marrow adjacent to the region of sclerosis appeared normal. There was no evidence of extraosseous soft-tissue changes. On both T1- and T2-weighted magnetic resonance imaging (MRI), the lesion exhibited low-signal intensity. The lesion measured 10.8×2.2×1 cm. It originated from the medial cortical bone of the tibia, blended into the medullary cavity, and extended anteriorly towards and through the anterior cortex. The area of cortical destruction was clearly evident on the axial MRI. The periosteum was displaced and eroded anteriorly by focal radiating bony streaks. No enhancement was seen after the intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) as a contrast medium. There were no extraosseous soft-tissue changes. In the distal part of the lesion, sagittal and axial MRI showed a 1.2×0.8×0.7-cm well-defined ovoid focus, with characteristics of cystic degeneration that exhibited intermediate-signal intensity on T1-weighted MRI (Figure 4) and high-signal intensity on T2-weighted MRI.

 

 

An open biopsy was performed. Macroscopically, a wedge of compact bone measuring 3×1.7×0.6 cm was taken. Microscopic examination showed a thinned periphery of lamellar (mature) bone with haversian canals and, beneath it, woven (immature) bone with long-surface processes projecting within adjacent cancellous bone (Figure 5A). The woven bone contained loose vascular fibrous tissue. No osteoclasts were noted, and the very few osteoblasts lining the bone trabeculae were small, single-layered, and flat (Figure 5B). There was no evidence of neoplastic cells. There was no abnormality of the periosteum and the surrounding soft tissues.

The histology was pathognomonic of a giant bone island. No additional surgical intervention was recommended.

The postoperative course was uncomplicated, and the patient was discharged 2 weeks later. An above-the-knee plaster was recommended for 3 months and a below-the-knee splint for an additional 2-month period. Full weight-bearing was allowed only after the postsurgical sixth month to prevent an impending fracture. The tibial bowing was tender to pressure or palpation, and the patient reported mild spontaneous pain during follow-up. Radiographs 1 year after surgery indicated that the bone area removed for biopsy was replaced by compact bone. MRI performed 4 years after surgery showed that the volume of the lesion in relation to the host bone was not changed.

 

At the last follow-up 15 years after surgery, the anterior tibial bowing was not changed (Figure 6A), but the patient additionally complained of skin irritation after intense training wearing boots during military service. The radiographic appearance of the lesion was also not changed, while the periphery of the lesion exhibited scarce radiating bony streaks with rounded contours (Figures 6B, 6C). The clinical symptoms and signs from wearing military boots completely subsided after a couple of weeks’ rest from daily army activities, but the mild spontaneous pain and the local tenderness over the tibial bowing persisted.

Discussion

Giant bone islands are more likely to be associated with clinical symptoms than the usual small-sized bone island. Some degree of pain was detected in 8 of 10 patients with a giant bone island presented in the literature, but it was induced by trauma in 3 of them.¹⁴

Radiographic appearance is among the distinguishing diagnostic features of a giant bone island. It appears as an ovoid, round, or oblong, homogenously dense, single or multiple focus of sclerosis within the medullary cavity; it is oriented along the long axis of the host bone, and it exhibits peripheral pseudopodia or radiating spicules producing the typical “thorny” or “paintbrush” appearance.^8,16,17 It does not exhibit cortical penetration and it is not associated with periosteal reaction.10

The CT findings include a sclerotic and hyperdense focus with spiculated margins extending into the adjacent cancellous bone. The lack of bone destruction and soft-tissue mass are also diagnostic.^3,7 MRI findings will reflect the low-signal intensity characteristics of cortical bone on all pulse sequences.¹⁸

Enostoses usually exhibit no activity on skeletal scintigraphy, while giant lesions generally show increased radiotracer uptake.^{5,9-11,14,19-27} The latter may result from the increased amount of bone turnover, which is seen more often with larger lesions because of active bone deposition and remodeling.^20,21,23,28 Histopathology of a giant bone island appears identical to the well-described pathologic appearance of smaller bone islands. The lesion is composed of compact lamellar bone and haversian systems, which blend with the adjacent spongiosa. The surrounding cancellous bone forms thorn-like trabeculae radiating from the lesion and merging with the cancellous bone.^1,4,5,8,28

The presumptive diagnosis of a bone island is based on the clinical findings, imaging features, and follow-up examinations. An asymptomatic, isolated, sclerotic bone lesion showing the typical features of a bone island on plain radiography, CT, and MRI, whatever its size, that is nonactive on bone scan may be easily diagnosed. However, a symptomatic patient with a hot lesion on scintigraphy should be carefully observed. In addition, larger lesions may raise the suspicion of a neoplasm, such as a sclerotic variant of osteosarcoma. In such cases, an open biopsy may be undertaken. No specific treatment is required after the diagnosis has been confirmed. There is no literature to suggest that, after adequate biopsy confirmation, excision or resection is necessary. Follow-up radiographic examination of the lesion should be suggested to monitor for any potential growth.^2,10,23

The first giant bone island appearing in a child is presented in this report. The lack of a causative factor leading to the anterior tibial bowing indicated that the bone deformity was caused primarily by the lesion. The present case is unusual for the appearance of several atypical features, some of which have not been previously described. Peripheral radiating spiculated margin was absent on the patient’s initial radiographs and CT imaging. MRI indicated only the presence of radiating bony streaks that displaced and eroded the periosteum on the anterior border of the lesion. The CT findings that the lesion likely originated or was in close proximity with the medial cortex of the tibia were also atypical. It has been previously reported that spinal lesions located immediately below the cortex tend to fuse with the endosteal surface, while similar features may also be seen in the appendicular enostoses.^4,29 Other CT findings, such as the thinning of the overlying anterolateral cortical bone, as well as the cortical thickening at the periphery of the lesion associated with areas of soft-tissue attenuation and anterior cortical destruction, have not been described even in the atypical features of a giant bone island. The lytic area resembling a nidus that was evident at the distal part of the lesion was more likely consistent with an area of resorption, which, although rare, has been described on giant lesions.^2,9,29 The substantial amount of woven bone transforming to lamellar bone that was evident in the present patient’s microscopic features is also an atypical finding, although it may be expected to some degree in scintigraphically hot, large lesions.²⁸ The clinical and imaging progress of the lesion supported the diagnosis of a giant bone island. The degree of the anterior tibial bowing and the volume of the lesion in relation to the host bone were not changed throughout the follow-up period, indicating that the growth of the lesion followed the growth of the normal bone.

 

The differential diagnosis of a giant bone island includes a variety of benign tumors and tumor-like lesions, as well as malignant bone lesions.^{2,4,23,28,30,31} In the patient presented in this report, the diagnosis of an atypical sclerotic presentation of a nonossifying fibroma or healing stage of this lesion could be consistent with some of the CT findings, including the eccentric origin from the cortex associated with medial cortical thickening, the anterolateral cortical thinning, and the soft-tissue attenuation of cortical areas. In addition, unifocal osteofibrous dysplasia may also present with a long intracortical diaphyseal lucency within an area of marked cortical sclerosis and cause a bowing deformity. Both diagnoses were excluded, since no fibrous stroma was evident on the histologic examination of the lesion. A large or giant long-bone osteoma would be associated with the outer cortical margin of bone but would not involve the intramedullary space. The scintigraphically increased uptake of radioisotope, as well as the CT and MRI findings, were not consistent with the diagnosis of osteoid osteoma, osteoblastoma, or osteomyelitis. Although most imaging findings were consistent with a benign lesion, and contrast-enhanced MRI showed no increased vascularity, anterior cortical disruption necessitated a bone biopsy to rule out any potential malignancy.

The histopathology in association with the clinical and imaging findings indicated the diagnosis of a giant bone island. The increased proportion of maturing woven bone over lamellar bone indicated an active remodeling lesion that could be related to the patient’s age, since the clinical and radiographic features of the lesion were not changed after 15-year follow-up.

Conclusion

This is the first giant bone island diagnosed in a patient before puberty. Its greatest length was 10.8 cm, which is the longest reported in the literature. The imaging appearance included several atypical features that are very rare or have not been reported. Microscopic features indicated less mature lamellar bone and a prominent proportion of maturing woven bone. The clinical and the radiographic appearance of the lesion were not changed after 15-year follow-up.

 A bone island is a focus of normal cortical bone located within the medullary cavity. The vast majority of bone islands are small, measuring from 1 mm to 2 cm in size. They are found more frequently in adults than in children. The lesion can be virtually diagnosed on the basis of its characteristic clinical and imaging features. Differential diagnosis may be difficult when the lesion manifests itself uncharacteristically by being symptomatic, very large, and hot on bone scan.^1-4

The term giant bone island has been used to describe a large lesion1 that measures more than 2 cm in any dimension.⁵ Giant bone islands have been described only in adults,^1,5-15 and the longest bone island length reported is 10.5 cm.¹⁰ They are usually symptomatic and associated with increased radionuclide uptake on bone scintigraphy.¹⁴

The history and the clinical and imaging presentation of an even longer, symptomatic, and scintigraphically hot lesion in the tibial diaphysis of a 10-year-old boy is reported. The lesion further exhibited several atypical imaging features necessitating an open biopsy, which confirmed the diagnosis of a giant bone island. The pertinent differential diagnosis and the clinical and radiographic findings after 15-year follow-up are also presented and discussed. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 10-year-old boy was admitted for surgical repair of an inguinal hernia. Physical examination revealed a painless but tender anterior bowing of the right tibial diaphysis. The patient was a healthy-appearing white male with normal vital signs, gait, and posture. His parents noticed a slight protuberance of the tibia at age 2.5 years. No medical advice was asked for the bone swelling after that time. After recovery from the inguinal hernia repair 3 weeks later, the bone lesion was thoroughly examined. Radiographs showed an oblong, homogenous region of dense sclerosis in the diaphysis of the right tibia. The lesion had relatively well-defined margins and was located in the medullary cavity. Speculations were not obvious in the periphery of the lesion, which exhibited a sharp circumscription (Figures 1A, 1B). A well-defined lytic area was evident at the distal part of the lesion (Figure 1B). There was no periosteal reaction. Blood and serum chemistries were within normal limits, including serum calcium, phosphorus, and alkaline phosphatase. A conventional 3-phase bone scintigraphy (300 MBq) with technetium-99m HDP (hydroxydiphosphonate) indicated increased uptake in the area of the lesion but no other skeletal abnormality (Figure 2). Computed tomography (CT) showed that the lesion was purely intramedullary and densely blastic. The lesion originated from the medial cortex, which was thickened (Figure 3A). The lesion extended to the anterolateral cortex, which was thinned and included a lytic area. In the distal part of the lesion, the anterolateral cortex was thickened, included lytic areas, and exhibited an anterior portion of cortical destruction (Figure 3B). The fatty marrow adjacent to the region of sclerosis appeared normal. There was no evidence of extraosseous soft-tissue changes. On both T1- and T2-weighted magnetic resonance imaging (MRI), the lesion exhibited low-signal intensity. The lesion measured 10.8×2.2×1 cm. It originated from the medial cortical bone of the tibia, blended into the medullary cavity, and extended anteriorly towards and through the anterior cortex. The area of cortical destruction was clearly evident on the axial MRI. The periosteum was displaced and eroded anteriorly by focal radiating bony streaks. No enhancement was seen after the intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) as a contrast medium. There were no extraosseous soft-tissue changes. In the distal part of the lesion, sagittal and axial MRI showed a 1.2×0.8×0.7-cm well-defined ovoid focus, with characteristics of cystic degeneration that exhibited intermediate-signal intensity on T1-weighted MRI (Figure 4) and high-signal intensity on T2-weighted MRI.

 

 

An open biopsy was performed. Macroscopically, a wedge of compact bone measuring 3×1.7×0.6 cm was taken. Microscopic examination showed a thinned periphery of lamellar (mature) bone with haversian canals and, beneath it, woven (immature) bone with long-surface processes projecting within adjacent cancellous bone (Figure 5A). The woven bone contained loose vascular fibrous tissue. No osteoclasts were noted, and the very few osteoblasts lining the bone trabeculae were small, single-layered, and flat (Figure 5B). There was no evidence of neoplastic cells. There was no abnormality of the periosteum and the surrounding soft tissues.

The histology was pathognomonic of a giant bone island. No additional surgical intervention was recommended.

The postoperative course was uncomplicated, and the patient was discharged 2 weeks later. An above-the-knee plaster was recommended for 3 months and a below-the-knee splint for an additional 2-month period. Full weight-bearing was allowed only after the postsurgical sixth month to prevent an impending fracture. The tibial bowing was tender to pressure or palpation, and the patient reported mild spontaneous pain during follow-up. Radiographs 1 year after surgery indicated that the bone area removed for biopsy was replaced by compact bone. MRI performed 4 years after surgery showed that the volume of the lesion in relation to the host bone was not changed.

 

At the last follow-up 15 years after surgery, the anterior tibial bowing was not changed (Figure 6A), but the patient additionally complained of skin irritation after intense training wearing boots during military service. The radiographic appearance of the lesion was also not changed, while the periphery of the lesion exhibited scarce radiating bony streaks with rounded contours (Figures 6B, 6C). The clinical symptoms and signs from wearing military boots completely subsided after a couple of weeks’ rest from daily army activities, but the mild spontaneous pain and the local tenderness over the tibial bowing persisted.

Discussion

Giant bone islands are more likely to be associated with clinical symptoms than the usual small-sized bone island. Some degree of pain was detected in 8 of 10 patients with a giant bone island presented in the literature, but it was induced by trauma in 3 of them.¹⁴

Radiographic appearance is among the distinguishing diagnostic features of a giant bone island. It appears as an ovoid, round, or oblong, homogenously dense, single or multiple focus of sclerosis within the medullary cavity; it is oriented along the long axis of the host bone, and it exhibits peripheral pseudopodia or radiating spicules producing the typical “thorny” or “paintbrush” appearance.^8,16,17 It does not exhibit cortical penetration and it is not associated with periosteal reaction.10

The CT findings include a sclerotic and hyperdense focus with spiculated margins extending into the adjacent cancellous bone. The lack of bone destruction and soft-tissue mass are also diagnostic.^3,7 MRI findings will reflect the low-signal intensity characteristics of cortical bone on all pulse sequences.¹⁸

Enostoses usually exhibit no activity on skeletal scintigraphy, while giant lesions generally show increased radiotracer uptake.^{5,9-11,14,19-27} The latter may result from the increased amount of bone turnover, which is seen more often with larger lesions because of active bone deposition and remodeling.^20,21,23,28 Histopathology of a giant bone island appears identical to the well-described pathologic appearance of smaller bone islands. The lesion is composed of compact lamellar bone and haversian systems, which blend with the adjacent spongiosa. The surrounding cancellous bone forms thorn-like trabeculae radiating from the lesion and merging with the cancellous bone.^1,4,5,8,28

The presumptive diagnosis of a bone island is based on the clinical findings, imaging features, and follow-up examinations. An asymptomatic, isolated, sclerotic bone lesion showing the typical features of a bone island on plain radiography, CT, and MRI, whatever its size, that is nonactive on bone scan may be easily diagnosed. However, a symptomatic patient with a hot lesion on scintigraphy should be carefully observed. In addition, larger lesions may raise the suspicion of a neoplasm, such as a sclerotic variant of osteosarcoma. In such cases, an open biopsy may be undertaken. No specific treatment is required after the diagnosis has been confirmed. There is no literature to suggest that, after adequate biopsy confirmation, excision or resection is necessary. Follow-up radiographic examination of the lesion should be suggested to monitor for any potential growth.^2,10,23

The first giant bone island appearing in a child is presented in this report. The lack of a causative factor leading to the anterior tibial bowing indicated that the bone deformity was caused primarily by the lesion. The present case is unusual for the appearance of several atypical features, some of which have not been previously described. Peripheral radiating spiculated margin was absent on the patient’s initial radiographs and CT imaging. MRI indicated only the presence of radiating bony streaks that displaced and eroded the periosteum on the anterior border of the lesion. The CT findings that the lesion likely originated or was in close proximity with the medial cortex of the tibia were also atypical. It has been previously reported that spinal lesions located immediately below the cortex tend to fuse with the endosteal surface, while similar features may also be seen in the appendicular enostoses.^4,29 Other CT findings, such as the thinning of the overlying anterolateral cortical bone, as well as the cortical thickening at the periphery of the lesion associated with areas of soft-tissue attenuation and anterior cortical destruction, have not been described even in the atypical features of a giant bone island. The lytic area resembling a nidus that was evident at the distal part of the lesion was more likely consistent with an area of resorption, which, although rare, has been described on giant lesions.^2,9,29 The substantial amount of woven bone transforming to lamellar bone that was evident in the present patient’s microscopic features is also an atypical finding, although it may be expected to some degree in scintigraphically hot, large lesions.²⁸ The clinical and imaging progress of the lesion supported the diagnosis of a giant bone island. The degree of the anterior tibial bowing and the volume of the lesion in relation to the host bone were not changed throughout the follow-up period, indicating that the growth of the lesion followed the growth of the normal bone.

 

The differential diagnosis of a giant bone island includes a variety of benign tumors and tumor-like lesions, as well as malignant bone lesions.^{2,4,23,28,30,31} In the patient presented in this report, the diagnosis of an atypical sclerotic presentation of a nonossifying fibroma or healing stage of this lesion could be consistent with some of the CT findings, including the eccentric origin from the cortex associated with medial cortical thickening, the anterolateral cortical thinning, and the soft-tissue attenuation of cortical areas. In addition, unifocal osteofibrous dysplasia may also present with a long intracortical diaphyseal lucency within an area of marked cortical sclerosis and cause a bowing deformity. Both diagnoses were excluded, since no fibrous stroma was evident on the histologic examination of the lesion. A large or giant long-bone osteoma would be associated with the outer cortical margin of bone but would not involve the intramedullary space. The scintigraphically increased uptake of radioisotope, as well as the CT and MRI findings, were not consistent with the diagnosis of osteoid osteoma, osteoblastoma, or osteomyelitis. Although most imaging findings were consistent with a benign lesion, and contrast-enhanced MRI showed no increased vascularity, anterior cortical disruption necessitated a bone biopsy to rule out any potential malignancy.

The histopathology in association with the clinical and imaging findings indicated the diagnosis of a giant bone island. The increased proportion of maturing woven bone over lamellar bone indicated an active remodeling lesion that could be related to the patient’s age, since the clinical and radiographic features of the lesion were not changed after 15-year follow-up.

Conclusion

This is the first giant bone island diagnosed in a patient before puberty. Its greatest length was 10.8 cm, which is the longest reported in the literature. The imaging appearance included several atypical features that are very rare or have not been reported. Microscopic features indicated less mature lamellar bone and a prominent proportion of maturing woven bone. The clinical and the radiographic appearance of the lesion were not changed after 15-year follow-up.

 A bone island is a focus of normal cortical bone located within the medullary cavity. The vast majority of bone islands are small, measuring from 1 mm to 2 cm in size. They are found more frequently in adults than in children. The lesion can be virtually diagnosed on the basis of its characteristic clinical and imaging features. Differential diagnosis may be difficult when the lesion manifests itself uncharacteristically by being symptomatic, very large, and hot on bone scan.^1-4

The term giant bone island has been used to describe a large lesion1 that measures more than 2 cm in any dimension.⁵ Giant bone islands have been described only in adults,^1,5-15 and the longest bone island length reported is 10.5 cm.¹⁰ They are usually symptomatic and associated with increased radionuclide uptake on bone scintigraphy.¹⁴

The history and the clinical and imaging presentation of an even longer, symptomatic, and scintigraphically hot lesion in the tibial diaphysis of a 10-year-old boy is reported. The lesion further exhibited several atypical imaging features necessitating an open biopsy, which confirmed the diagnosis of a giant bone island. The pertinent differential diagnosis and the clinical and radiographic findings after 15-year follow-up are also presented and discussed. The patient provided written informed consent for print and electronic publication of this case report.

Case Report

A 10-year-old boy was admitted for surgical repair of an inguinal hernia. Physical examination revealed a painless but tender anterior bowing of the right tibial diaphysis. The patient was a healthy-appearing white male with normal vital signs, gait, and posture. His parents noticed a slight protuberance of the tibia at age 2.5 years. No medical advice was asked for the bone swelling after that time. After recovery from the inguinal hernia repair 3 weeks later, the bone lesion was thoroughly examined. Radiographs showed an oblong, homogenous region of dense sclerosis in the diaphysis of the right tibia. The lesion had relatively well-defined margins and was located in the medullary cavity. Speculations were not obvious in the periphery of the lesion, which exhibited a sharp circumscription (Figures 1A, 1B). A well-defined lytic area was evident at the distal part of the lesion (Figure 1B). There was no periosteal reaction. Blood and serum chemistries were within normal limits, including serum calcium, phosphorus, and alkaline phosphatase. A conventional 3-phase bone scintigraphy (300 MBq) with technetium-99m HDP (hydroxydiphosphonate) indicated increased uptake in the area of the lesion but no other skeletal abnormality (Figure 2). Computed tomography (CT) showed that the lesion was purely intramedullary and densely blastic. The lesion originated from the medial cortex, which was thickened (Figure 3A). The lesion extended to the anterolateral cortex, which was thinned and included a lytic area. In the distal part of the lesion, the anterolateral cortex was thickened, included lytic areas, and exhibited an anterior portion of cortical destruction (Figure 3B). The fatty marrow adjacent to the region of sclerosis appeared normal. There was no evidence of extraosseous soft-tissue changes. On both T1- and T2-weighted magnetic resonance imaging (MRI), the lesion exhibited low-signal intensity. The lesion measured 10.8×2.2×1 cm. It originated from the medial cortical bone of the tibia, blended into the medullary cavity, and extended anteriorly towards and through the anterior cortex. The area of cortical destruction was clearly evident on the axial MRI. The periosteum was displaced and eroded anteriorly by focal radiating bony streaks. No enhancement was seen after the intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) as a contrast medium. There were no extraosseous soft-tissue changes. In the distal part of the lesion, sagittal and axial MRI showed a 1.2×0.8×0.7-cm well-defined ovoid focus, with characteristics of cystic degeneration that exhibited intermediate-signal intensity on T1-weighted MRI (Figure 4) and high-signal intensity on T2-weighted MRI.

 

 

An open biopsy was performed. Macroscopically, a wedge of compact bone measuring 3×1.7×0.6 cm was taken. Microscopic examination showed a thinned periphery of lamellar (mature) bone with haversian canals and, beneath it, woven (immature) bone with long-surface processes projecting within adjacent cancellous bone (Figure 5A). The woven bone contained loose vascular fibrous tissue. No osteoclasts were noted, and the very few osteoblasts lining the bone trabeculae were small, single-layered, and flat (Figure 5B). There was no evidence of neoplastic cells. There was no abnormality of the periosteum and the surrounding soft tissues.

The histology was pathognomonic of a giant bone island. No additional surgical intervention was recommended.

The postoperative course was uncomplicated, and the patient was discharged 2 weeks later. An above-the-knee plaster was recommended for 3 months and a below-the-knee splint for an additional 2-month period. Full weight-bearing was allowed only after the postsurgical sixth month to prevent an impending fracture. The tibial bowing was tender to pressure or palpation, and the patient reported mild spontaneous pain during follow-up. Radiographs 1 year after surgery indicated that the bone area removed for biopsy was replaced by compact bone. MRI performed 4 years after surgery showed that the volume of the lesion in relation to the host bone was not changed.

 

At the last follow-up 15 years after surgery, the anterior tibial bowing was not changed (Figure 6A), but the patient additionally complained of skin irritation after intense training wearing boots during military service. The radiographic appearance of the lesion was also not changed, while the periphery of the lesion exhibited scarce radiating bony streaks with rounded contours (Figures 6B, 6C). The clinical symptoms and signs from wearing military boots completely subsided after a couple of weeks’ rest from daily army activities, but the mild spontaneous pain and the local tenderness over the tibial bowing persisted.

Discussion

Giant bone islands are more likely to be associated with clinical symptoms than the usual small-sized bone island. Some degree of pain was detected in 8 of 10 patients with a giant bone island presented in the literature, but it was induced by trauma in 3 of them.¹⁴

Radiographic appearance is among the distinguishing diagnostic features of a giant bone island. It appears as an ovoid, round, or oblong, homogenously dense, single or multiple focus of sclerosis within the medullary cavity; it is oriented along the long axis of the host bone, and it exhibits peripheral pseudopodia or radiating spicules producing the typical “thorny” or “paintbrush” appearance.^8,16,17 It does not exhibit cortical penetration and it is not associated with periosteal reaction.10

The CT findings include a sclerotic and hyperdense focus with spiculated margins extending into the adjacent cancellous bone. The lack of bone destruction and soft-tissue mass are also diagnostic.^3,7 MRI findings will reflect the low-signal intensity characteristics of cortical bone on all pulse sequences.¹⁸

Enostoses usually exhibit no activity on skeletal scintigraphy, while giant lesions generally show increased radiotracer uptake.^{5,9-11,14,19-27} The latter may result from the increased amount of bone turnover, which is seen more often with larger lesions because of active bone deposition and remodeling.^20,21,23,28 Histopathology of a giant bone island appears identical to the well-described pathologic appearance of smaller bone islands. The lesion is composed of compact lamellar bone and haversian systems, which blend with the adjacent spongiosa. The surrounding cancellous bone forms thorn-like trabeculae radiating from the lesion and merging with the cancellous bone.^1,4,5,8,28

The presumptive diagnosis of a bone island is based on the clinical findings, imaging features, and follow-up examinations. An asymptomatic, isolated, sclerotic bone lesion showing the typical features of a bone island on plain radiography, CT, and MRI, whatever its size, that is nonactive on bone scan may be easily diagnosed. However, a symptomatic patient with a hot lesion on scintigraphy should be carefully observed. In addition, larger lesions may raise the suspicion of a neoplasm, such as a sclerotic variant of osteosarcoma. In such cases, an open biopsy may be undertaken. No specific treatment is required after the diagnosis has been confirmed. There is no literature to suggest that, after adequate biopsy confirmation, excision or resection is necessary. Follow-up radiographic examination of the lesion should be suggested to monitor for any potential growth.^2,10,23

The first giant bone island appearing in a child is presented in this report. The lack of a causative factor leading to the anterior tibial bowing indicated that the bone deformity was caused primarily by the lesion. The present case is unusual for the appearance of several atypical features, some of which have not been previously described. Peripheral radiating spiculated margin was absent on the patient’s initial radiographs and CT imaging. MRI indicated only the presence of radiating bony streaks that displaced and eroded the periosteum on the anterior border of the lesion. The CT findings that the lesion likely originated or was in close proximity with the medial cortex of the tibia were also atypical. It has been previously reported that spinal lesions located immediately below the cortex tend to fuse with the endosteal surface, while similar features may also be seen in the appendicular enostoses.^4,29 Other CT findings, such as the thinning of the overlying anterolateral cortical bone, as well as the cortical thickening at the periphery of the lesion associated with areas of soft-tissue attenuation and anterior cortical destruction, have not been described even in the atypical features of a giant bone island. The lytic area resembling a nidus that was evident at the distal part of the lesion was more likely consistent with an area of resorption, which, although rare, has been described on giant lesions.^2,9,29 The substantial amount of woven bone transforming to lamellar bone that was evident in the present patient’s microscopic features is also an atypical finding, although it may be expected to some degree in scintigraphically hot, large lesions.²⁸ The clinical and imaging progress of the lesion supported the diagnosis of a giant bone island. The degree of the anterior tibial bowing and the volume of the lesion in relation to the host bone were not changed throughout the follow-up period, indicating that the growth of the lesion followed the growth of the normal bone.

 

The differential diagnosis of a giant bone island includes a variety of benign tumors and tumor-like lesions, as well as malignant bone lesions.^{2,4,23,28,30,31} In the patient presented in this report, the diagnosis of an atypical sclerotic presentation of a nonossifying fibroma or healing stage of this lesion could be consistent with some of the CT findings, including the eccentric origin from the cortex associated with medial cortical thickening, the anterolateral cortical thinning, and the soft-tissue attenuation of cortical areas. In addition, unifocal osteofibrous dysplasia may also present with a long intracortical diaphyseal lucency within an area of marked cortical sclerosis and cause a bowing deformity. Both diagnoses were excluded, since no fibrous stroma was evident on the histologic examination of the lesion. A large or giant long-bone osteoma would be associated with the outer cortical margin of bone but would not involve the intramedullary space. The scintigraphically increased uptake of radioisotope, as well as the CT and MRI findings, were not consistent with the diagnosis of osteoid osteoma, osteoblastoma, or osteomyelitis. Although most imaging findings were consistent with a benign lesion, and contrast-enhanced MRI showed no increased vascularity, anterior cortical disruption necessitated a bone biopsy to rule out any potential malignancy.

The histopathology in association with the clinical and imaging findings indicated the diagnosis of a giant bone island. The increased proportion of maturing woven bone over lamellar bone indicated an active remodeling lesion that could be related to the patient’s age, since the clinical and radiographic features of the lesion were not changed after 15-year follow-up.

Conclusion

This is the first giant bone island diagnosed in a patient before puberty. Its greatest length was 10.8 cm, which is the longest reported in the literature. The imaging appearance included several atypical features that are very rare or have not been reported. Microscopic features indicated less mature lamellar bone and a prominent proportion of maturing woven bone. The clinical and the radiographic appearance of the lesion were not changed after 15-year follow-up.