Vascular injury after occult knee dislocation presenting as compartment syndrome

Popliteal artery injury can occur in up to one-third of patients with knee dislocation. Delay in the diagnosis of popliteal artery injury is the leading cause of amputation in this limb-threatening injury.

To remind emergency physicians to consider popliteal artery injury in any pulseless lower extremity, even in cases of spontaneous reduction of the knee dislocation before evaluation by medical personnel.

We present a case of popliteal artery injury and occult knee dislocation in which the diagnoses were delayed for hours by incorrectly attributing the absence of posterior tibial and dorsalis pedis pulses to compartment syndrome. The correct diagnosis was made after operative release of lower extremity compartment pressures, when it was noted that distal vascular flow remained absent. A computed tomography angiogram demonstrated complete rupture of the popliteal artery and magnetic resonance imaging performed later revealed total disruption of both cruciate ligaments, as well as posterolateral ligaments.

As absence of distal pulses is a very late finding in compartment syndrome, it should be considered a result of arterial injury in patients with lower extremity trauma until proven otherwise.