Abstract
OBJECTIVES:
To evaluate mediating factors for the effect of therapeutic exercise on pain and physical function in people with knee/hip osteoarthritis (OA).
METHODS:
For Subgrouping and TargetEd Exercise pRogrammes for knee and hip OsteoArthritis (STEER OA), individual participant data (IPD) were sought from all published randomised controlled trials (RCTs) comparing therapeutic exercise to non-exercise controls in people with knee/hip OA. Using the Counterfactual framework, the effect of the exercise intervention and the percentage mediated through each potential mediator (muscle strength, proprioception and range of motion (ROM)) for knee OA and muscle strength for hip OA were determined.
RESULTS:
Data from 12 of 31 RCTs of STEER OA (1407 participants) were available. Within the IPD data sets, there were generally statistically significant effects from therapeutic exercise for pain and physical function in comparison to non-exercise controls. Of all potential mediators, only the change in knee extension strength was statistically and significantly associated with the change in pain in knee OA (β -0.03 (95% CI -0.05 to -0.01), 2.3% mediated) and with physical function in knee OA (β -0.02 (95% CI -0.04 to -0.00), 2.0% mediated) and hip OA (β -0.03 (95% CI -0.07 to -0.00), no mediation).
CONCLUSIONS:
This first IPD mediation analysis of this scale revealed that in people with knee OA, knee extension strength only mediated ±2% of the effect of therapeutic exercise on pain and physical function. ROM and proprioception did not mediate changes in outcomes, nor did knee extension strength in people with hip OA. As 98% of the effectiveness of therapeutic exercise compared with non-exercise controls remains unexplained, more needs to be done to understand the underlying mechanisms of actions.
| Original language | English |
|---|---|
| Article number | e003220 |
| Journal | RMD Open |
| Volume | 9 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 28 Aug 2023 |
Bibliographical note
Funding Information:The STEER OA project, of which this analysis was part, was supported by a Grant from the Chartered Society of Physiotherapy Charitable Trust (grant number PRF/16/A07), and the National Institute for Health Research (NIHR) School of Primary Care Research (grant number 531). JR received a Fellowship from the Foundation for Research in Rheumatology (FOREUM). KD (ID NIHR 200259) and NEF are NIHR Senior Investigators. KD is part funded by the National Institute for Health and Care Research (NIHR) Applied Health Research Collaboration (ARC) West Midlands (NIHR 200165). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. JQ was part-funded by an NIHR CRN West Midlands Research Scholarship and part funded by the Haywood Foundation. ELH is part funded by the NIHR Applied Research Collaboration (ARC) West Midlands. The OA Trial Bank receives long-term funding from the Dutch Arthritis Society.
Publisher Copyright:
© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.