Lower Limb Amputations - Distal or Proximal to the Ankle? - That is the Question

Introduction: The avid surgeon is faced with an ever ongoing dilemma: where to draw the line of amputation. Often, the attempts to perform ankle preserving amputations seem futile and even harmful to our patients. The aim of this study was to examine the mortality rate of patients after various amputations at different levels of the lower limb.

Methos: We retrospectively reviewed 696 patients who underwent lower limb amputations at various levels, during the years 2002-2014, at Kaplan Medical Center. Amputations were classified as distal to ankle amputations (DAA) and proximal to ankle amputations (PAA). Data was collected and charted with emphasis on co-morbidities, time to amputation, occurrence of re-amputation, one-year mortality and five-year mortality.

Results: 375 patients underwent initial DAA amputation (53.8%). Eighty four (22.4%) of these patients required conversion of amputation (COA) from DAA to PAA. The success rate of distal amputation, defined as the patients that did not require conversion to PAA was 77.8% (291/375).

The overall 5 year mortality in our study was 54% (377/696), while the 1- year mortality 35.7% (249/696). The 5-year mortality of the initial PAA group was significantly (p=0.002) higher than that of the DAA group, 68.8% (221/321) versus 42.13% (158/375), respectively. Similarly, the 1 year mortality of initial PAA group was significantly (p=0.002) higher than the DAA was 54.8% (176/321) versus 17.5% (51/291), respectively.

The 5 year mortality among the group of patients who were converted to proximal amputation (COA) was 60.7% (51/84) while their 1 year mortality was 26.2% (22/84). Subsequently, the 1 year mortality rate was significantly (p=0.002) lower than the PAA, and significantly (p=0.03) higher than the DAA.

Conclusion: Based on our data we contend that reasonable attempts to perform DAA and avoid unwarranted PAA may improve the 1 and five year survival of candidates for lower limb amputation.