Systemic and local risk factors for major amputation following diabetic minor amputation

Diabetes-related foot complications could lead to amputation and death. Major amputations are known to yield higher mortality rate compared to minor amputations. In patients who already had a minor diabetic amputation, knowing the risk factors contributing to a major re-amputation is of great importance. This study aims to quantify the risk of major amputation following minor diabetic amputation and to investigate the systemic and local risk factors of the re-amputation event.

This is a retrospective comparative study among patients who had a minor amputation as a diabetic complication where one group had no subsequent amputation (Group 1) versus another group with subsequent major amputation (Group 2). The minimum follow-up period was of 24 months. The main outcomes were set as the frequency of major re-amputation and the independent systemic and the local risk factors such as wound healing complications, stump issues and the impact of using MRI-guided level for index amputation.

Out of the 107 index amputations (97 patients), 70 cases (65 patients) did not present with subsequent amputations (Group 1) and 18 patients/cases (16.8 %) required a major amputation at the last follow-up (Group 2). The logistic regression analysis showed peripheral artery disease (PAD) and non MRI-guided index minor amputation as independent factors for higher subsequent major amputations (p = 0.04 and p = 0.02, respectively).

The risk of a major amputation following a diabetic minor amputation is not infrequent, almost 17 %. PAD was found to be the only independent systematic factor to positively correlate with the risk of major re-amputation. MRI-guided level of index amputation, at least 1 cm proximal to MRI bone infection sign, was significantly negatively correlated with re-amputation.