To determine the frequency and type of arterial injuries associated with complete dislocation of the knee and to correlate the findings at physical examination with those at arteriography, a computerized search for patients with a diagnosis of dislocation of the knee at discharge from an urban trauma hospital was performed. Nineteen patients with complete dislocation of the knee were found. Arterial injuries were seen in six patients (32%). Four of the 19 patients had no pedal pulse at physical examination. In three of these four patients, occlusion of the popliteal artery was seen on arteriograms. The fourth patient had occlusion of an anomalous anterior tibial artery and a compartmental syndrome. Two of the 15 other patients with pedal pulses (13%) had nonoccluding intimal defects of the popliteal artery; these two patients did well without surgery. It is concluded that abnormal peripheral pulses associated with complete knee dislocation are highly predictive of major arterial injury. If peripheral pulses are normal, a low but definite frequency of arterial damage exists.