Multivariate Profiling of Physical Resilience in Older Adults After Total Knee Replacement Surgery: Results from a Prospective Observational Study

Background As individuals age, their ability to cope with and recovering from health challenges becomes vital for maintaining independence and quality of life. This study aims to develop a multivariate phenotype of physical resilience based on individual recovery dynamics before and after a physical stressor. Methods This prospective observational study included 104 individuals aged ≥ 60 who underwent elective total knee replacement (TKR) for degenerative joint disease between December 2, 2019, and January 4, 2023. A multivariate resilience phenotype was derived from physical function assessments over 12 months after TKR using the Short Physical Performance Battery, the Pittsburgh Fatigability Scale Physical Subscale, the Knee Injury and Osteoarthritis Outcome Quality of Life Score, and the 36-Item Short Form Health Survey Physical Component Score. Validation was performed using markers (i.e., frailty and self-reported health) and determinants (e.g., the Charlson Comorbidity Index (CCI)) of recovery potential. Results Distinct resilience profiles were identified across the four measures, showing varied baseline levels and/or change rates over 12 months. By combining and analyzing resilience profiles across measures, two distinct groups emerged: 33.7% were classified as non-resilient and 66.4% as resilient. The non-resilient group had a higher prevalence of frailty (37.1% vs. 10.1%, p<0.01), poor or fair self-reported health (48.6% vs. 5.8%, p<0.01), and moderate or severe comorbidity burden (CCI >2; 28.6% vs. 10.1%, p=0.03). Conclusions Recovery trajectories after TKR revealed varying resilience levels that could not be fully explained by baseline health status. Understanding individual resilience can enhance patient care by promoting recovery and overall well-being.