A reappraisal of a modified through-knee amputation in patients with peripheral vascular disease

Background: Through-knee amputation provides a longer lever arm and improved muscle control of the limb compared with above-knee amputation. Through-knee amputation also allows use of a total end-bearing prosthesis, which avoids the ischial pressure and suspension belts required of the above-knee amputation prosthesis. Several reports in the European literature tout the superiority of the through-knee amputation over the above-knee amputation in the patient with vascular disease. Through-knee amputation has received little attention in the United States, however, owing to the belief that the long flaps necessary to close a standard through-knee amputation are associated with an unacceptable rate of wound problems and offer no functional ambulatory advantage to above-knee amputation. We reviewed our experience with a modified technique of through-knee amputation in a group of patients with severe lower extremity ischemia who were not candidates for below-knee amputation to determine the incidence of wound complications and their functional outcome. Methods: Since 1996, 12 patients with severe lower extremity arterial insufficiency have undergone through-knee amputation utilizing a technique designed to limit flap length and facilitate the fit of a suction prosthesis. Two patients died of myocardial infarction in the immediate postoperative period and were excluded from the study. In the remaining 10 patients (1 man, 9 women; mean age 63 years (range 40 to 86), the below-knee amputation level was precluded because of gangrene or nonhealing wounds of the mid leg in 5 patients, failure of a previous below-knee amputation attempt in 4 patients, and severe ischemia that would compromise below-knee amputation healing in 1 patient. Nine patients had at least one failed vascular reconstruction procedure. Results: Mean follow-up is 25 months (range 6 to 41). Six (60%) patients had primary healing of their amputations. Two (20%) patients had delayed healing (6 weeks and 8 weeks). Two (20%) patients developed wound infections, which required amputation revision to the above-knee level. Seven (70%) patients were fitted with a suction socket prosthesis and are fully ambulatory. One patient healed but has not ambulated because of ischemia and subsequent ulceration of the contralateral limb. Conclusions: These data show that through-knee amputation is associated with an acceptable primary healing rate (80%) and satisfactory functional outcomes (70% ambulation) in a high-risk vascular population. The functional advantages of through-knee amputation over above-knee amputation make it the preferred alternative for patients with vascular disease.