Background: Popliteal artery injury is frequently associated with knee dislocation following blunt trauma, an injury that is being seen with increasing frequency. The primary purpose of the present study was to evaluate the use of physical examination to determine the need for arteriography in a large series of patients with knee dislocation. The secondary purpose was to evaluate the correlation between physical examination findings and clinically important vascular injury in the subgroup of patients who underwent arteriography. Methods: One hundred and thirty consecutive patients (138 knees) who had sustained an acute multiligamentous knee injury were evaluated at our level-1 trauma center between August 1996 and May 2002 and were included in a prospective outcome study. Four patients (four knees) were lost to follow-up, leaving 126 patients (134 knees) available for inclusion in the study. The results of the physical examination of the vascular status of the extremities were used to determine the need for arteriography. The mean duration of follow-up was nineteen months (range, eight to forty-eight months). Physical examination findings, magnetic resonance imaging findings, and surgical findings were combined to determine the extent of ligamentous damage. Results: Nine patients had flow-limiting popliteal artery damage, for an overall prevalence of 7%. Ten patients had abnormal findings on physical examination, with one patient having a false-positive result and nine having a true-positive result. The knee dislocations in the nine patients with popliteal artery damage were classified, according to the Wascher modification of the Schenck system, as KD-III (one knee), KD-IV (seven knees), and KD-V (one knee). Conclusions: Selective arteriography based on serial physical examinations is a safe and prudent policy following knee dislocation. There is a strong correlation between the results of physical examination and the need for arteriography. Increased vigilance may be justified in the case of a patient with a KD-IV dislocation, for whom serial examinations should continue for at least forty-eight hours. Level of Evidence: Diagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference "gold" standard]).