Below-Knee Amputation Failure and Poor Functional Outcomes Are Higher Than Predicted in Contemporary Practice

Area of Science:

• Vascular Surgery
• Amputation Outcomes
• Limb Salvage

Background:

• Below-knee amputation (BKA) is performed with the aim of preserving limb function.
• However, the functional benefits must be weighed against the risk of reintervention and failure.
• The endovascular era has shifted amputation decision-making, necessitating updated outcome data.

Purpose of the Study:

• To evaluate contemporary clinical and functional outcomes of patients undergoing BKA.
• To assess factors associated with BKA failure, including conversion to above-knee amputation (AKA) and mortality.
• To examine the role of transcutaneous oximetry (TcPO2) in predicting BKA success.

Main Methods:

• Retrospective review of 130 BKAs in 120 patients from 2008-2014.
• Data collected included demographics, comorbidities, ambulation status, and TcPO2.
• End points: freedom from AKA conversion, freedom from AKA or death, BKA healing, and ambulation.

Main Results:

• 38% of BKA patients healed and ambulated postoperatively.
• 25% required reintervention, with 24% converting to AKA.
• One-year freedom from AKA was 76%, and freedom from AKA/death was 60%. Lower TcPO2 (<40 mmHg) was associated with significantly higher rates of AKA conversion and death.

Conclusions:

• Most patients undergoing BKA in the endovascular era do not achieve successful ambulation.
• Decreased TcPO2 levels (<40 mmHg) are a strong predictor of BKA failure (AKA conversion or death).
• Careful patient selection and shared decision-making are crucial for optimizing outcomes in this frail population.