Review Question - QID 214235

This child sustained a SH II distal femur fracture with resultant physeal arrest and has roughly 6 years of growth remaining. His current leg length discrepancy will worsen over time, resulting in a >5cm discrepancy (2cm of discrepancy at age 11, 5 years of growth remaining with ~1cm per year = 7cm projected discrepancy), thereby making lengthening of the right femur the correct answer.

The most common complication of pediatric distal femur fractures is growth disturbance, occurring in up to 60% of patients. Treatment for leg length discrepancies is based on the projected discrepancy at skeletal maturity: patients with a projected LLD < 2cm are best treated with observation or a shoe lift, while those with a projected LLD of 2-5cm are treated with epiphysiodesis of the unaffected side and those with a projected LLD > 5cm treated with limb lengthening of the affected side.

Basener et al. performed a meta-analysis looking at distal femur growth plate fractures. They found that 52% of distal femoral growth plate fractures had some sort of growth disturbance and 22% of patients developed a leg length discrepancy of greater than 1.5 cm. SH I had the lowest incidence of growth disturbance (36%), while SH IV had the highest rate at 64%.

Arkader et al. report that both SH classification and displacement of the fracture are significant predictors of the final outcome. They found that the SH classification was significantly correlated with the rate of complications. There was also a significantly higher rate of complications in fractures that were displaced. The amount and direction of displacement did not correlate with outcome, however. They also noted a higher rate of complications if hardware violated the physis.

Figure A is an AP radiograph of a SH II distal femur fracture. Figure B is a fluoroscopic image demonstrating fixation of a distal femur fracture using lag screws.

Incorrect Answers:
Answer 1: Observation is indicated in patients with a projected LLD < 2cm. This patient has an expected LLD > 5cm so observation would therefore be inappropriate.
Answers 2 and 3: Epiphysiodesis is indicated in patients with a projected LLD of 2-5cm. This patient has an expected LLD > 5cm so epiphysiodesis alone would therefore be inappropriate.
Answer 5: Right tibial osteotomy and lengthening at or near skeletal maturity is the appropriate treatment for patients with an expected LLD > 5cm; however, in this patient, it should be performed in the femur to keep the knee heights symmetric.