Risk Factors for Failure of Transmetatarsal Amputation in Diabetic Patients: A Cohort Study

Introduction: This study analysed the factors affecting wound healing of a transmetatarsal amputation (TMA) in patients with diabetes. Materials and Methods: Twenty-one patients who failed a TMA and were revised to transtibial amputation (TTA) within the first year were compared with a matched cohort of 21 successful TMA's. The factors compared included demographics, systemic issues, and local conditions in the foot. Chi-square comparisons were used for group data, and Analysis of Variance (ANOVA) for numeric data. Results: Blood glucose control as measured by HbA1c was the most important single factor predicting the success of TMA. Need for debridement after TMA was also found to be a significant predictor of failure of TMA. There was a trend towards duration of ulcer prior to TMA and smoking being significant. All other variables, including vascular status or renal failure were not significantly different between the two groups. Conclusion: The primary factor determining the success of a TMA was the quality of glucose control. The results of this study can be extrapolated to diabetic patients undergoing other types of surgery, with preoperative diabetic control as measured by HbA1c being an important determinant of the outcome of surgery. As a result of this study we currently do not perform any elective, trauma or emergency surgery on diabetic patients with an HbA1c of over 8 unless the need for surgery is to save life or limb.