Peri-surgical changes in functional capabilities associated with reconstructive knee surgery
This thesis, using a meta-analytical review of the literature and a controlled longitudinal cohort trial, addresses a knowledge gap regarding peri-surgical changes in self-reported and objective measures of physical function, neuromuscular and sensorimotor performance capabilities of patients undergoing total knee arthroplasty (TKA). Responsiveness and patterns of change in perceived exertion (Borg Category-Ratio Scale [CR-10]), perceived task duration (PTD) and neuromuscular performance during an intermittent isometric fatigue task (IIF) were also investigated. Twenty-six individuals (50 % female, 66.8 ± 1.4 years) underwent evaluation at 3 and ~12 weeks pre-surgery, and again at 6 and 12 weeks post-operatively. Patient-reported outcomes including the Knee injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS), 36-Item Short Form Health Survey (SF-36), Performance Profile and International Physical Activity Questionnaire demonstrated significant changes in peri-surgical functional status. Significant time related interactions between operated and control legs were observed for range of movement, knee circumference and neuromuscular performance indices of volitional peak force (PFV), rate of force development, rate of force relaxation, electromechanical delay activation and relaxation (vastus medialis). Items of the KOOS (pain and activities of daily living), OKS and SF-36 (role emotional) and PFV demonstrated significant differences at three weeks pre-surgery compared to baseline. Differences in the rate of change of performance at week 6 and week 12 post-surgery contributed most to the overall interactive- and main effect-related changes in the selected outcome measures. In estimating patient perceptions of exercise stress in an environment mimicking aspects of self-managed rehabilitative conditioning, the Borg Category-Ratio Scale and PTD showed a differential pattern of change during a novel IIF, with the latter perceptual tool showing congruency with patterns of objective fatigue-related loss of performance. This thesis provides the most comprehensive evaluation of peri-surgical physical function using patient-reported and objective (physical and physiological performance) outcomes. Further, this study is the first to contribute insight into how people undergoing TKA perceive exercise exertion and task duration. The research presents possible directions of future research to optimise physical function of TKA recipients.