The Outcome Assessment Requires Both Performance-Based and Patient-Reported Measures After Revision Total Knee Arthroplasty

Abstract

Purpose: To investigate the correlation between performance-based and patient-reported measures and their relation with knee muscle strength in the assessment of revision total knee arthroplasty (rTKA) patients. Materials and Methods: This cross-sectional study recruited 92 patients with rTKA. The outcome assessment was performed using three performance tests (the Timed Up and Go (TUG), 30-second Chair Stand Test (30CST), and 50-Foot Walking Test (50FWT)) and one patient-reported questionnaire (the Hospital for Special Surgery (HSS)). The maximum isometric muscle strength of knee flexors and knee extensors was assessed with Handheld Dynamometry (HHD). Results: The total HSS knee score showed low significant associations with performance-based tests (all, p< 0.05), but no associations with knee muscles strength. The knee extensor strength showed moderate to strong significant associations with all performance tests, while the knee flexor strength had a low to moderate significant correlation with these performance tests (all, p<0.05). Conclusion: Our findings, which show a low correlation between performance-based tests and patient-reported questionnaire, suggest patient perception fails to accurately capture the functioning at the late follow-up of rTKA. Therefore, performance-based tests should be included in the outcome assessment to determine an appropriate rehabilitation program and exercise training after rTKA. Moreover, the higher associations between functional tests and knee muscle strength than the associations of the questionnaire with these performance measures advocate this assertion. These findings could be crucial in informing the design and implementation of interventions tailored to this population.