Physical measures predicting better outcomes in knee arthroplasty patients: a secondary analysis of the CORKA randomised controlled trial.

Abstract

Evaluate functional and participation predictors of outcome following knee arthroplasty (KA) focusing on theInternational Classification of Functioning, Disability, and Health framework. Secondary analysis of the CORKA randomised controlled trial, which included patients undergoing KA. The primary outcome was the Late-Life Function and Disability Instrument (LLFDI) was assessed using a linear mixed-effects model. Secondary outcomes with baseline assessments of the Physical Activity Scale for the Elderly (PASE), Figure of 8 Walk Test (F8WT), 30-Second Chair Stand Test (30CST), and single-leg stance on the operated leg (SLS) were used to predict functional and participation outcomes at 6, 12, and 24-months using multiple linear regression models. 621 participants were recruited (males 250, females 371), with a mean age of 70 ± 8 years. SLS significantly predicted LLFDI function across all time points (6-months 0.14, 0.06-0.22, p = 0.001, 12-months 0.18, 0.09-0.27, p < 0.001, 24-months 0.21, 0.11-0.31, p < 0.001), while PASE predicted it at 6-months 0.02, 0.01-0.03, p = 0.006 and 24-months 0.02, 0.004-0.04, p = 0.012. PASE also predicted disability frequency at all intervals(6-months 0.03, 0.02-0.05, p < 0.001, 12-months 0.04, 0.02-0.05, p < 0.001, 24-months 0.03, 0.01-0.05, p = 0.001), with SLS and F8WT as significant predictors at 12 and 24-months, respectively (SLS 12-months 0.13, 0.04-0.21, p = 0.005, F8WT 24-months -0.37, -0.73 to -0.01, p = 0.044). Only PASE (12-months 0.04, 0.01-0.07, p = 0.003, 24-months 0.04, 0.01-0.07, p = 0.003) and SLS (12-months 0.26, 0.10-0.42, p = 0.002, 24-months 0.28, 0.12-0.44, p = 0.001) predicted disability limitation at 12 and 24-months. Findings suggest functional measures may be used to predict short-term outcomes, while participation measures better suit long-term outcomes after KA.