Functional Outcome of Above-Knee Amputation After Infected Total Knee Arthroplasty

Background Periprosthetic joint infection is a serious complication of total knee arthroplasty (TKA). Management usually involves irrigation and debridement, polyethylene liner exchange, one-stage revision, two-stage revision, knee arthrodesis, or ultimately above-knee amputation (AKA). We present our experience with 21 patients who underwent AKA as a sequela of unresolved infected TKA, highlighting their etiology and functional outcomes. Methods A retrospective chart review was performed for all cases of infected TKA treated with AKA at 1 institute from January 2007 to December 2020, with a minimum follow-up of 1 year. Patient demographics, Charlson comorbidity index, culture results, ambulation status, prosthesis fitting, and functional outcomes were collected. Short Form-36 and activities of daily living questionnaires were used for functional outcome assessment. Results Twenty-one patients were identified, 7 of whom were male (33.3%). Mean ± standard deviation follow-up was 5.7 ± 3.1 years (range, 1-11 years). Mean ± standard deviation age was 57.9 ± 10.7 years (range, 38-87 years), and the mean body mass index was 33.5 ± 6.4 kg/m 2 (range, 25.4-46 kg/m 2 ). Gram-positive organisms were identified in 15 cases (66.7%). Prosthesis fitting was successful in 17 patients (81%). Post-AKA ambulation was achieved in 12 patients (57.1%). The ambulating group showed higher Short Form-36 and activities of daily living scores when compared with patients who did not ambulate (60.2 vs 43.3, P = .041, and 67.2 vs 52.7, P = .029, respectively). Conclusions AKA should be considered solely as the final recourse for infected TKA. Despite the low-to-moderate patient-reported postoperative outcomes, prosthesis fitting and maintaining ambulation can improve postoperative functional outcomes.