Predictors of healing and functional outcome following transmetatarsal amputations

Objectives: To evaluate factors that predict healing and to assess functional outcome and survival following transmetatarsal amputations (TMAs) for forefoot gangrene. Design: Retrospective case-control study. Setting: University hospital. Patients: All patients undergoing TMA from January 1, 2004, through December 31, 2010. Intervention: Transmetatarsal amputations performed in all patients. Main Outcome Measures: Transmetatarsal amputation healing, ambulation, living status, and survival. Demographic characteristics, preoperative vascular status, and perioperative variables were analyzed as predictor variables. Univariate and multivariate analyses were performed to determine predictors of healing and survival. Results: Sixty-two TMAs were performed in 57 patients. Healing occurred in 33 TMAs (53%), with 22 TMAs (35%) in patients who proceeded to below-knee amputation and 7 TMAs (11%) in patients who died without healing. No demographic or perioperative variables significantly predicted healing. Independent ambulation was achieved in 24 patients with healed TMAs (73%) but in only 4 patients with nonhealed TMAs (14%) (P < .001). Mean survival was 16.5 months (range, 0-94 months), with no difference between patients with healed and those with nonhealed TMA. Significant predictors of mortality were dialysis-dependent renal failure (odds ratio, 4.85; 95% confidence interval, 1.01-23.30) (P = .047), non-independent living (17.80; 3.03-104.80) (P = .001), and need for preoperative revascularization (4.80; 1.24-18.50) (P = .02). Conclusions: Transmetatarsal amputations have low healing rates, and patient demographic characteristics and preoperative assessment do not help predict healing. Transmetatarsal amputation healing, however, significantly predicts subsequent ambulatory status and should be pursued in patients with good rehabilitation potential.