179 Duration of Physical Activity Following Total Hip or Knee Replacement: An Analysis of the Epic-Norfolk Cohort

Abstract

Background: It has been suggested that following total hip (THR) and knee replacement (TKR) people increase their levels of physical activity as a result of reduced pain and increased range of motion. Engagement in physical activity is important for promoting physical and mental health and reducing the burden of non-communicable diseases on primary and secondary care services. Therefore, joint replacement is hypothesized to have wider health benefits in addition to improvement of joint pain and disability. However, the degree to which physical activity increases following THR and TKR is unknown. This study answered this question with a UK population cohort, the European Prospective Investigation of Cancer (EPIC)-Norfolk. We determined whether there was a change in the duration of physical activity following THR or TKR; if the duration of physical activity changes following THR or TKR, which specific forms of physical activity are altered and by how much; and which characteristics or variables predicted an absolute change in duration of physical activity following THR or TKR. Methods: In total, 653 people from the EPIC-Norfolk community cohort were identified who had undergone primary THR or TKR between EPIC Health Check 2 (1998–2001) and 3 (2006–2011). Paired t-test and multivariable regression analyses were conducted to determine whether there was a change in pre- vs post-arthroplasty duration of physical activity [assessed through duration of waking hours, stair climbing, activities of extended daily living (in and around the home), time spent undertaking physically active recreational pursuits]. Paired t-test analyses were undertaken to assess the change in physical activity over time, while a multivariable regression analysis modelled the absolute change in physical activity measures against potential explanatory factors such as age, gender and co-morbidities. Results: There was a statistically significant reduction from pre- to post-arthroplasty duration of daily stair climbing at home [THR: mean difference 6.19 (95% CI 2.88, 9.50), P < 0.01; TKR: mean difference 9.42 (95% CI 3.00, 15.43), P < 0.01] and time spent participating in recreational activities [THR: mean difference 1.10 (95% CI 0.26, 1.95), P = 0.03]. There was no statistical difference in pre- to post-arthroplasty change in physical activity duration for the other activities. Only age was consistently associated with the duration of physical activity change, whereby older people pre-arthroplasty demonstrated the least change in duration of physical activity. Conclusion: The duration of physical activity does not increase and may actually decrease following THR and TKR for some domains, most notably stair climbing. This is contrary to previous understanding. Accordingly, greater education by primary and secondary care services at pre- and post-operative stages should be provided to patients on their expected change and/or their potential change in physical activity post-arthroplasty. This is warranted given the benefits physical activity confers on physical and mental health.