Eleven of 202 patients operated for acute knee instability from 1976 to 1988 showed an associated popliteal vascular injury. No patient with intact posterior cruciate ligament had a vascular lesion, and all patients with popliteal vascular injury had a ruptured posterior cruciate ligament. Our patients are analyzed with respect to clinical symptoms of the ischemia, management and results at assessment. Prompt recognition and early revascularisation with debridement of all grossly damaged arterial wall, a tension-free reconstruction and the liberal use of fasciotomy is the key to improved limb salvage.