MUSCLE FUNCTION, FUNCTIONAL PERFORMANCE, BIOMECHANICAL AND SELF-REPORTED IMPAIRMENTS AFTER TOTAL KNEE ARTHROPLASTY

Abstract

Knee osteoarthritis (OA) is a common disease affecting older people. Total knee arthroplasty (TKA) is the most common surgical intervention for advanced knee OA, and it usually achieves good outcomes for patients. However, some patients retain impairments in self-reported pain, activity limitation, or quality of life (QoL) after TKA. Muscle function, functional performance, physical activity, and/or gait biomechanics may influence these outcomes, however, this had rarely been investigated. The primary aim of this thesis was to determine if pain, activity limitation or QoL 12 months after TKA were predicted by muscle function, functional performance, physical activity, or gait biomechanics six months after TKA. A systematic review (Chapter 2) showed no study had predicted self-reported outcomes at 12 months from muscle function or functional performance at least three months after TKA. Chapter 3 showed that among performance-based measures (knee extensor strength, stair climbing power, and walking speed) at six months, only knee extensor strength predicted self-reported outcomes at 12 months. Chapter 4 evaluated sex differences in performance and self-reported outcomes at six and 12 months after TKA. While walking speed and self-reported outcomes did not differ between men and women, normalised knee extensor strength and stair climbing power were higher among men. Chapter 5 showed that neither physical activity (steps per day, time in moderate and vigorous activities) nor sedentary behaviour at six months predicted self-reported outcomes 12 months after TKA. Chapter 6 examined prediction of the self-reported outcomes from selected gait biomechanics. Lower first knee extensor moment peak and better QoL (SF-12 mental component summary score) six months after TKA predicted better QoL (SF-12 MCS) 12 months after TKA. These findings will guide clinicians and patients regarding prognosis of self-reported outcomes and rehabilitation targets after TKA.