High early complication risk but low risk of re‐revision beyond 5 years following revision knee arthroplasty in the elderly: An analysis of 2833 cases using real‐world data from an international database

PURPOSE: With an increasing global elderly population, the number of revision total knee arthroplasties (rTKAs) in patients aged ≥80 years is rising. However, outcomes in this age group remain difficult to report and poorly understood. This study aimed to evaluate clinical outcomes, 90-day complication rates and long-term implant survivorship after rTKA in patients aged ≥80 years, and to compare results between revisions for aseptic loosening and prosthetic joint infection (PJI). METHODS: Data were extracted from TriNetX, a global healthcare database covering 21 countries. Patients aged ≥80 years undergoing rTKA were included. Outcomes assessed included 90-day complications and mortality, crude re-revision rates at 2, 5 and 10 years, and implant and patient survivorship. Propensity score-matched analysis compared outcomes between aseptic loosening and PJI cohorts. Cox regression identified predictors of 90-day mortality and 2-year re-revision risk. RESULTS: A total of 2833 patients were included. Ninety-day mortality was 2.7%. Acute kidney injury (AKI) was the most frequent complication (9.9%), particularly among PJI patients (18.2%). Crude re-revision rates were 9.3%, 10.4% and 10.5% at 2, 5 and 10 years, respectively, while implant survivorship was 87.7%, 83.6% and 81.8%. Ten-year patient survivorship was 38.8%. Patients with PJI had higher comorbidity burdens and postoperative complication rates. After matching, PJI patients showed increased risk of 90-day mortality (relative risk [RR] = 2.00, p = 0.051) and AKI (RR = 1.91, p < 0.001). Cox regression confirmed PJI as an independent predictor of 90-day mortality (hazard ratio [HR] = 2.51, p = 0.008) and 2-year re-revision (HR = 1.70, p = 0.001). CONCLUSIONS: Elderly patients undergoing rTKA for PJI exhibit greater comorbidity, higher complication rates and increased early mortality compared to those revised for aseptic loosening. Re-revision beyond 5 years is uncommon. In this population, outcomes such as mortality, mobility and quality of life may be more clinically meaningful than long-term implant survivorship. LEVEL OF EVIDENCE: Level IV.