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.