A 12-year-old boy is brought to the emergency department by his parents to evaluate pain and swelling in his right ankle. The boy was riding his skateboard when he attempted a jump and landed awkwardly on his foot. He has not been able to put weight on his leg since the injury. On examination, there is diffuse swelling of the right ankle with no visible deformity. Examination is limited as any attempted motion of the ankle causes severe pain. Bilateral distal pulses are normal. Sensation is intact. Radiographs of the ankle partially visualize a fracture of the distal tibia. A CT scan of the fracture is shown below: This patient's fracture places him at increased risk for which of the following complications?

Question

A 12-year-old boy is brought to the emergency department by his parents to evaluate pain and swelling in his right ankle.  The boy was riding his skateboard when he attempted a jump and landed awkwardly on his foot.  He has not been able to put weight on his leg since the injury.  On examination, there is diffuse swelling of the right ankle with no visible deformity.  Examination is limited as any attempted motion of the ankle causes severe pain.  Bilateral distal pulses are normal.  Sensation is intact.  Radiographs of the ankle partially visualize a fracture of the distal tibia.  A CT scan of the fracture is shown below:  This patient's fracture places him at increased risk for which of the following complications?

Quizplus · Accepted Answer

11ec25c8_d976_c8c7_bc81_dfa145549ccf_MD0003_00 This patient has an ankle injury with diffuse swelling and an inability to bear weight; initial imaging with x-ray is appropriate, although a CT scan may be needed to fully visualize a fracture. The CT scan reveals a combination of: a distal tibial epiphysis fracture; and a growth plate (ie, physeal) fracture, as suggested by growth plate widening. This combination of fractures is known as a Salter-Harris type III (juvenile Tillaux fracture). Salter-Harris type III The distal tibial growth plate typically closes around age 14 in boys (age 12 in girls), and fractures involving the maturing, partially fused, physis (eg, Salter-Harris type III and IV fractures) carry an increased risk for long-term complications. In particular, injury to the growth plate can cause growth arrest and lead to persistent limb-length discrepancy. Other complications include formation of physeal bars (bony bridges across the growth plate), premature osteoarthritis, and decreased range of motion. (Choice A) Acute limb ischemia is most often due to arterial occlusion. When seen with limb fractures, it typically occurs soon after high-velocity femoral fractures and would be accompanied by signs of vascular impairment (eg, loss of distal pulses, reduced sensation, pallor, cyanosis). (Choice B) Post-fracture avascular necrosis is most common in areas of bone with limited blood supply such as the scaphoid, femoral head, or metadiaphyseal junction of the fifth metatarsal, but it is uncommon in distal tibia fractures. scaphoid femoral head metadiaphyseal junction of the fifth metatarsal (Choice C) Compartment syndrome results from increased pressure within nondistensible fascial planes. It is uncommon in ankle fractures because the bulk of the leg muscle bellies are proximal to the injury. (Choice E) Traumatic foot drop is typically caused by injury to the common peroneal nerve where it wraps around the lateral neck of the proximal fibula. Distal fractures of the tibia or fibula would not cause foot drop. Educational objective: A Salter-Harris type III (juvenile Tillaux fracture) is characterized by fracture of the distal tibial epiphysis and lateral physis (ie, growth plate) and most commonly occurs in adolescents when the physis is partially fused. Injury to the growth plate can cause growth arrest and lead to persistent limb-length discrepancy. References: Treatment for displaced Tillaux fractures in adolescent age group. (http://www.ncbi.nlm.nih.gov/pubmed/31031149)

A 12-Year-Old Boy Is Brought to the Emergency Department by His