Risk factors for transtibial amputation after minor amputation in diabetic foot patients

Diabetic foot ulcers are a serious complication of diabetes, often leading to deep tissue infections, osteomyelitis and gangrene, with subsequent risk of amputations. Diabetic foot disease (DFD) affects 15-25% of diabetic patients and 15% of these cases require amputation. This study aims to investigate factors associated with transtibial amputation following minor amputation.

A retrospective analysis was conducted on diabetic patients who underwent minor amputation for DFD at a tertiary center between 2012 and 2022. Minor amputations were defined as those occurring between toes and ankle joint, while transtibial amputations were those occurring between the ankle and knee joint within 6 months of a minor amputation. Clinical and demographic data were collected and analyzed.

A total of 93 patients were included in the study, with 66 in the minor amputation group and 27 in major amputation group. There were no significant differences in age (p = 0.793) or gender (p = 0.500). Inflammatory markers and blood tests showed no significant differences between the groups. The presence of osteomyelitis (p = 0.047) and the number of surgical debridements required (p < 0.001) were significantly higher in the major amputation group. The ROC curve analysis indicated that number of surgical debridements was a strong predictor for transtibial revision (AUC = 0.838).

The presence of osteomyelitis and need for multiple surgical debridements are associated with higher risk of transtibial amputation following minor amputation in diabetic patients. Prospective, randomized controlled studies with larger patient samples are needed to confirm these findings.