Through-knee amputation in patients with peripheral arterial disease: a review of 50 cases.

BACKGROUND

For good rehabilitation candidates, the biomechanical advantages of the end weight-bearing through-knee amputation (TKAmp) compared with the above knee amputation (AKA) are well established. However, the TKAmp has been abandoned by vascular surgeons because of poor wound healing rates related to long tissue flaps and challenges to prosthetic fitting related to the femoral condyles. Since 1998, we have performed the modified "Mazet" technique TKAmp procedure that creates shorter flaps to close the wound and greatly facilitates prosthesis fitting. The purpose of this study is to review our results with TKAmp in patients with peripheral vascular disease who were not candidates for below-knee amputation.

METHODS

The records of all patients who underwent through-knee amputation between 1998 and 2006 were retrospectively reviewed. Mean follow-up was 33 months (range, 38 days to 99 months). Amputations for trauma and malignancy were excluded. Patient survival, maintenance of ambulation, and independent living status were analyzed using Kaplan-Meier survival analysis methods.

RESULTS

Fifty patients underwent TKAmp using a modified Mazet technique. The mean age was 63 years; 50% were men, and 50% had diabetes mellitus. All patients had peripheral arterial disease. Thirty-five patients (70%) had prior revascularization procedures. Those patients averaged 2.2 revascularization procedures prior to amputation. There were three (6%) perioperative deaths. The ipsilateral common femoral artery was patent in 43/50 (86%) of patients at the time of amputation. Forty patients (80%) had open wounds and three patients (6%) had a failed below-knee amputation at the time of TKAmp. Thirty-eight patients (81%) healed their TKAmp wound. Nine patients failed to heal and were revised to an above knee amputation. The cumulative probability of regular prosthetic usage and maintenance of ambulation was estimated to be 0.56 at 3 years and 0.41 at 5 years. The probability of maintaining independent living status at 3 and 5 years was 0.77 and 0.65, respectively. Survival probabilities for patients in this series were 0.60 at 3 years and 0.44 at 5 years.

CONCLUSION

These data show that the TKAmp is associated with an acceptable primary healing rate and satisfactory functional outcomes in patients with peripheral arterial disease. The advantages of TKAmp over AKA make it the preferred alternative for patients with vascular disease who are candidates for prosthetic rehabilitation.