Incidence of Above-Knee Amputation Following Total Knee Arthroplasty: A Comprehensive Analysis from a Midwestern Metropolitan Hospital System
Abstract
Background Rates of total knee arthroplasty (TKA) in the United States exceed 800,000 annually and are projected to surpass 1.2 million by 2040. The reported infection rate following primary TKA was approximately 2% in 2023 . Above-knee amputation (AKA) is considered a terminal salvage procedure for failed TKA refractory to other treatments. Historical data from 1970–2000 reported an AKA rate of 0.36% following TKA. This study aimed to evaluate whether the rate of AKA per primary TKA has changed in a contemporary cohort. Methods A retrospective study was conducted using the HCA Midwest Health System database to identify patients treated between 2016 and 2022 who underwent AKA (CPT 27590). ICD-10 codes were used to evaluate comorbidities, body mass index (BMI), demographic characteristics, and microbiologic data. Primary TKA cases were identified using CPT 27447, and operative reports were reviewed to confirm the indication for amputation. Associations between comorbidities and progression to AKA were evaluated using independent t-tests and chi-square analyses. Results A total of 360 AKA cases were identified, of which 255 met inclusion criteria after exclusions. Thirty AKAs were attributable to failed TKA, including prosthetic joint infection (PJI) and arthrofibrosis. During the study period, 9,900 primary TKAs were performed. The incidence of AKA following primary TKA was 0.29% (29/9,900 No statistically significant associations were identified; however, the study was underpowered to detect modest differences because of the small number of events.). Conclusion The incidence of AKA per primary TKA remains comparable to historical reports. Above-knee amputation represents a rare but catastrophic salvage outcome following failed TKA. Continued surveillance of this outcome and other severe complications is warranted given evolving surgical techniques, implant technology, and increasing procedural volume.