Review Question - QID 214102

The patient has sustained a significantly displaced Salter Harris (SH) II distal femur fracture with posterior angulation. These injuries have an increased likelihood of vascular injuries. Given the reduced ABI (< 0.9), the next best step would be urgent reduction, percutaneous pinning/screw fixation, and then reassessing vascular status.

Displaced SH distal femur injuries should be treated as a dislocation of the knee and therefore, as a medical emergency. A high clinical suspicion should be present for a vascular injury even in the presence of pulses. In the setting of possible vascular injury, reduction and fixation should be performed followed by reassessment of the vascular status. In the presence of a vascular artery injury, patients will need undergo emergency vascular reconstruction or repair.

Wall and May reviewed the complication rates of distal femur growth plate fractures. They noted that these fractures often necessitate operative intervention, even in the youngest patients and even with minimal apparent displacement. Poor outcomes have been associated with pediatric fracture care of SH III and IV distal femurs. They conclude that complication rates are as high as 60% and include malunion, growth arrest, and posttraumatic arthritis.

McKenna et al. evaluated SH-type injuries of the distal femur. They note that these injuries should be treated as dislocations of the knee and therefore as a medical emergency. The authors note ABI ratio should be measured in all patients and the clinician should have a high index of suspicion for a vascular injury. Ideally reduction, stabilization, and vascular repair, if necessary, should be carried out within 6 hours of the initial event. There should be a low threshold for fasciotomies in the event of a vascular repair.

Illustrated A is the CT angiogram that shows the kinking of the popliteal vessel caused by the displacement of the distal femur physeal fracture.

Incorrect Answers:
Answer 1: Emergent fasciotomy should be performed in patients who have high clinical suspicion for compartment syndrome, or at that time of vascular repair after a long period of ischemia.
Answer 2: Fixation of distal femoral physeal fractures should avoid plate fixation across the physis if possible.
Answer 3: An MRI may be needed to confirm a physeal injury in the event of a non-displaced physeal fracture but plays no role in a clearly displaced distal femur physeal fracture.
Answer 5: A reduction should be performed with a reassessment of pulses prior to vascular exploration and repair.