Through-Knee Amputation in Patients With Peripheral Arterial Disease: A Review of 50 Cases

Background: For the patient who is a good candidate for prosthetic rehabilitation, the biomechanical advantages of the end weight-bearing through-knee amputation (TKA) compared to the above knee amputation are well established. However, the TKA has been abandoned by vascular surgeons due to the concern that the long tissue flaps needed to close the wound over the femoral condyles is associated with poor wound healing. Furthermore, the bulbous femoral condyles present challenges to prosthetic fitting. Consequently, over the past four decades there have been few reports in the literature reporting the outcome of TKA for the patient with peripheral arterial disease.
Since 1998 we have performed a TKA procedure that removes the patella and shaves the femoral condyles. This modified "Mazet" technique requires shorter flaps to close the wound and greatly facilitates prosthesis fitting and donning by the patient.
The purpose of this study is to review our results with TKA 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 1996 and 2005 were retrospectively reviewed. Mean follow-up was 32.8 months (range, 2 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 life table methods.
Results: Between 1996 and 2005, 50 patients underwent TKA using a modified Mazet technique. The mean age was 63.3 years; 36% were men, 50% had diabetes mellitus, and 100% had peripheral arterial disease. Thirty-five patients (70%) had prior revascularization procedures. Those patients averaged 2.2 revascularization procedures prior to amputation. 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 3 patients (6%) had a failed below knee amputation at the time of TKA. Forty-one patients (82%) healed their TKA wound. Nine patients failed to heal and were revised to an above knee amputation. Regular prosthetic usage and maintenance of ambulation was achieved in 55% of patients at 3 years and 41% of patients at 5 years. Independent living status was maintained in 77% and 65% of patients at 3 and 5 years respectively. Survival for patients in this series was 60% at 3 years and 44% at 5 years.
Conclusions: These data show that the TKA is associated with an acceptable primary healing rate and satisfactory functional outcomes in patients with peripheral arterial disease. The functional advantages of TKA over AKA make it the preferred alternative for patients with vascular disease who are candidates for prosthetic rehabilitation.