Below-knee Amputations Are Associated with Decreased Mortality and Reoperation in Elderly, Dependent Patients with Atherosclerotic Disease

Abstract

Patients with dependent functional status are often offered above-knee amputations (AKAs), even if a below-knee amputation (BKA) could be an option, because AKA heals more easily than BKA. However, there is little data that directly compares the outcomes of these procedures in dependent patients to support this practice. The American College of Surgeons National Surgical Quality Improvement Program was used to identify functionally dependent patients who underwent non-traumatic BKA and AKA for atherosclerotic disease from 2005 to 2021. Emergent cases and those with preoperative sepsis and wound infections were excluded. The studied outcomes were 30-day mortality, major organ dysfunction, wound complications, and unplanned return to the operating room. Multivariable analysis was used. Institutional data from 2017 to 2022 on patients with BKA and AKA were included to provide more granular details about perfusion status of the legs by angiogram to predict the healing success of BKA. A total of 2399 patients were identified in the National Surgical Quality Improvement Program; 1039 underwent BKA and 1360 underwent AKA. BKA was associated with lower mortality (adjusted odds ratio [aOR], 0.60; P ≤ .001) and stroke (aOR, 0.14; P = .009) but higher wound complications (aOR, 1.87; P ≤ .001) and reoperation (aOR, 1.88; P ≤ .001) when compared with AKA (Table I). Preoperative imaging from 66 BKA patients was reviewed from institutional data to investigate factors associated with reoperation or BKA failure. There were 17 patients (25%) who failed a BKA and needed conversion to an AKA. Reoperation occurred at an average of 52 ± 37 days postoperatively. The status of the profunda appeared to make little difference; those failed BKA requiring AKA conversion were more likely to have occlusion of the popliteal artery when compared with those with successful BKA (69.2% vs 34.3%; P = .03) (Table II). Elderly, dependent patients requiring lower extremity amputation should initially be considered for BKA, as this is associated with decreased risk for mortality and reoperation when compared with AKA. Clinical judgement should be used in patients with popliteal occlusion, as this may contribute to BKA failure requiring conversion to AKA.Table IFactors predictive of mortality, wound complications, and reoperation in patients with below-knee amputation (BKA) and above-knee amputation (AKA)Adjusted odds ratio95% confidence intervalP-valueBKA MortalityHypoalbuminemiaa2.521.45-4.41.001Thrombocytopeniab2.681.41-5.08.003 Wound complicationsAge >70 years0.691.03-1.04.080 ReoperationAge >70 years0.560.32-0.83.004AKA MortalityChronic obstructive pulmonary disease1.611.03-2.51.036Congestive heart failure2.811.46-3.71<.001Dialysis dependence2.331.15-2.99<.001Steroid use2.171.15-4.10.017Thrombocytopeniab1.881.18-2.99.008 Wound complicationsBody mass index >30 kg/m21.931.14-3.28.014 ReoperationAge >70 years0.520.31-0.87.013Dialysis dependence1.891.05-3.37.031aSerum albumin less than 3.4 mg/dL.bSerum platelets less than 150 × 109/mL. Open table in a new tab Table IIPreoperative imaging scoring demonstrates prevalence of patent popliteal artery among patients with healed below-knee amputation (BKA) when compared with failed BKAHealed BKAFailed BKAP-valueTotal patients, n (%)4917Profunda stenosis.433 0-75% stenosis32 (91.4)10 (83.3) 76-100% stenosis3 (8.6)2 (16.7)Profunda disease length.091 0-2 cm34 (97.1)10 (83.3) 2->5 cm1 (2.9)2 (16.7)Patent popliteal23 (65.7)4 (30.8).030Patent SFA26 (74.3)10 (76.9).915Data are presented as number (%). Open table in a new tab