Assessing Physical Function in Bilateral and Unilateral Total Knee Arthroplasty Patients.

Abstract

The general objective of this dissertation was to investigate physical function in osteoarthritis (OA) and total knee replacement (TKA) patients. First, a validation study was performed to evaluate the validity of the Continuous Scale Physical Functional Performance (CS-PFP10) test in knee OA awaiting TKA. The CS-PFP10 scores were compared to the Western Ontario and McMaster Universities OA Index (WOMAC), The Knee Society’s Clinical Rating System (KSS), and the Short Form 36-item health survey (SF-36) physical function scores. It was hypothesized that at least moderate associations between the CS-PFP10 test scores and the WOMAC, KSS, and SF-36 scores in TKA candidates exist. The results of this study indicated moderate to strong associations between the CS-PFP10 and other physical function scores (r=.474 to .598, p<.001) showing that the CS-PFP10 is a valid tool for measuring physical function in OA/TKA patients. The second study was a 12-week prospective study investigating the return of physical function in TKA patients following surgery. We also examined the sensitivity of the CS-PFP10 test to change in TKA patients. The hypotheses of this investigation included that the CS-PFP10 would be sensitive to functional changes in TKA patients and that the magnitude of effect sizes during the initial recovery period following surgery (between 3 and 6 weeks post-op) would be greatest for the CS-PFP10 and the KSS. Finally, we hypothesized that improvements in objective measures of function would not be affected by dispositional optimism, but the subjective measures would be. Consistent with our hypotheses, the results demonstrated a functional incline over the time course of the study. The effect sizes of the follow-up data suggest that the CS-PFP10 is sensitive in detecting change in function over time, even in a small group of patients. Unexpectedly, the CS-PFP10 indicated an initial drop in physical function immediately after surgery (3 weeks post), while the other tests did not. These findings indicate that there are differences in perceived and performance-based physical function and could be an indication of the CS-PFP10 being a more sensitive measure of function when compared to the other instruments.