Review Question - QID 210202

The patient suffered a distal femur fracture involving the physis. These injuries often lead to growth disturbances leading to either angular deformity or a leg length discrepancy. Given her proximity to skeletal maturity (2 years remaining), the projected leg length discrepancy would be less than 2cm and can be followed clinically.

Distal femoral physeal fractures are often seen among adolescents after high energy sporting collision, usually from a valgus-directed force. The epiphysis separates on the tension side while the metaphysis fractures on the compression side, producing a Salter Harris type II pattern. Physeal disturbances are common after these injuries and all treatments should be done in a manner to avoid further damage. With this in mind, reduction should be done under general sedation to allow gentle reduction, and if anatomic reduction can be maintained closed, percutaneous pinning or screw fixation should be performed sparing the physis when possible. If the projected leg length inequality after this injury would be greater than 2cm, a contralateral physeal procedure may be necessary if growth arrest observed after the index procedure; otherwise, these can be followed closely until maturity.

Basener et al. performed a meta-analysis of growth disturbances following distal femoral physeal fractures. They found a 52% overall rate of growth disturbance, with nondisplaced fractures having a 31% rate of growth disturbance and initially displaced fractures having a 65% rate. Salter-Harris type IV fracture patterns had the highest incidence of growth disturbance. This demonstrates the significance that even nondisplaced fractures may lead to physeal arrest.

Figure A is an AP radiograph showing a Salter-Harris II fracture involving the physis of the distal femur.

Incorrect Answers:
Answer 1: Avascular necrosis is not commonly described following these injuries
Answer 2: While knee stiffness is seen after distal physeal injuries, it is not the most common complication
Answer 4: If this patient had more growth remaining, and growth arrest was observed, growth modulation of the contralateral side would be warranted if the calculated LLD was greater than 2cm
Answer 5: If the projected LLD were greater than 5cm, ipsilateral limb lengthening procedures would be indicated