The impact of self-efficacy for physical activity on health-related quality of life in total knee arthroplasty recipients.

Background: Some patients with end-stage osteoarthritis of the knee remain unsatisfied after total knee arthroplasty (TKA). We postulated that to increase satisfaction, self-efficacy (SE) for physical activity should receive more attention in rehabilitative intervention, alongside the management of patient expectations, pain, and function.

Objective: We examined the relative impact of Physical Activity SE on Health-Related Quality of Life (HRQOL) alongside other factors such as pain and physical function which are well-addressed by current interventions.

Methods: One hundred and six first-TKA recipients (15 Male/91 Female, age 73.6 ± 7.2) were evaluated at 3 and 6 months post-operatively using the Medical Outcomes Study 36-Item Health Survey (SF-36v2) for HRQOL, knee extension strength measurement, Timed Up and Go test (TUG), One Leg Standing time test (OLS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) for pain and function, and an instrument for measuring Physical Activity SE among the frail elderly in Japan.

Results: Significant improvement over pre-operative values was found at 3 and 6 months in TUG, OLS, WOMAC Pain and Function, and the 8 subscales of the SF-36v2. Factors found to significantly impact SF-36v2 subscale scores at 6 months post-operatively were found to be knee pain, knee function, and SE for physical activity.

Conclusion: These results support our postulation that interventions to improve SE for physical activity could have comparable impact alongside interventions for knee pain and knee function, on the advancement of HRQOL among TKA recipients.