Below-knee amputation: is the effort to preserve the knee joint justified?

The records of 50 patients (31 men and 19 women, ranging in age from 49 to 89 years) undergoing definitive below-knee amputation for ischemia from May 1971 to May 1979 were reviewed. Forty-three (86%) had ulceration or necrosis involving the foot or toes. Seven had rest pain without tissue loss. Overall healing rate was 86%. Seven patients (14%) failed to heal and required reamputation above the knee; the functional status of the remaining 43 patients was graded preoperatively and at the time of late follow-up (mean, 3.4 years). Twenty-five of 35 (71%) unilateral below-knee amputees could walk with a prosthesis; ten could not. Seventeen patients (34%) either required an additional, higher amputation or did not use the knee joint to increase mobility. The patient with marginal circulation and marked preoperative functional limitations may have the above-knee level as the chosen site for amputation.