Healing of transmetatarsal amputation in the diabetic patient: is angiography predictive?

Transmetatarsal amputation (TMA) is a durable reconstruction in the diabetic patient with limited forefoot gangrene. However, predicting TMA healing remains difficult. Our goals were to (1) determine the success rate of TMA and (2) identify factors predictive of TMA healing, in particular arterial foot anatomy. A retrospective review of all diabetic patients undergoing TMA was done. Blood supply to the foot was classified as mostly anterior (anterior tibial and/or dorsalis pedis artery), mostly posterior (posterior tibial or plantar arteries), or equally distributed (both systems patent or peroneal runoff). Foot vessels were assigned runoff scores from 0 to 3 according to Society for Vascular Surgery/International Society for Cardiovascular Surgery (SVS/ISCVS) criteria. Forty-four TMAs in 29 men and 12 women were reviewed. Revascularization was done in 35 cases. In nine cases (20%), no bypass was deemed necessary (n = 7) or feasible (n = 2). Blood flow to the foot was deemed mostly anterior in 16 cases, mostly posterior in 17 cases, and equally distributed in 11. The TMA was left open in 19 cases and closed with staples or sutures in the rest. Limb salvage was achieved in 30 cases (68%) at a median follow-up of 48 weeks. Three of the four patients on dialysis required leg amputation (75%) vs. 11 of the 40 (27%) nondialysis patients (p = 0.05). When the TMA was left open, leg amputation was more likely (58%) than when closed primarily (12%) (p < 0.01). No angiographic factors were predictive of limb salvage. The need for revascularization was not associated with limb loss, although both patients with no feasible bypass option required below-knee amputation. TMA healing can be expected in a majority of diabetic patients after adequate revascularization but cannot be predicted by angiographic findings. Efforts should be made to achieve primary wound closure.