Combined orthopedic and vascular injury in the lower extremities: indications for amputation. A retrospective review was undertaken to determine risk factors associated with amputation after open fractures of the lower extremity that were complicated by vascular injury. During an 11-year period ending in December 1987, we observed open fractures in 31 patients and injuries to the popliteal artery in 16 patients, to the tibial arteries in eight patients, to the femoral artery in five patients, and to the dorsal artery of the foot in two patients. Vascular repair was accomplished in 25 patients; 12 patients had primary end-to-end anastomosis, 12 patients had reverse saphenous vein grafts, and one patient had a bovine graft. Of these 25 patients, five patients required amputation because of infection and three patients required amputation because of continued ischemia. Three patients with irreparable damage had immediate amputation, and three patients without distal ischemia had vessel ligation only. The risk factors associated with amputation were shock on admission (10 of 19 patients [p less than 0.02]) and a crushed extremity (10 of 18 patients [p less than 0.01]). The overall amputation rate, which included three immediate amputations and eight late amputations, was 35.2%. The data suggest that limb salvage is possible in two thirds of patients with combined orthopedic and vascular injuries of the lower extremity, but a history of shock or crush injury with vascular compromise is an unfavorable prognostic sign. 