Currently, over 230,000 total hip arthroplasties (THA) are performed each year in the United States to alleviate pain and disability associated with osteoarthritis (OA). However, full recovery of muscle strength and function after hip arthroplasty remains a major challenge. A major factor influencing full recovery of physical function is the presence of chronic movement compensations, which may be the biggest rehabilitative challenge after THA. These movement compensations reflect failure to fully remediate strength losses resulting from hip OA and THA as well as a failure to integrate muscle strength gains into functional movement. Functional strength integration during performance of functional tasks refers to the ability of the body to produce stable, coordinated movements. Around the hip joint, optimal functional strength integration is largely dependent on the ability of hip abductor muscles to produce hip abduction moments, which stabilize the pelvis during unilateral stance tasks. Thus, inability to integrate hip abductor strength during functional tasks leads to lower hip abduction moments during functional tasks, resulting in poor pelvic stability and movement compensations. This lack of functional strength integration possibly explains lingering deficits in functional recovery after THA. However, current rehabilitation practices do not target the integration of strength and functional movement to resolve movement compensations for improved physical function. A rehabilitation program emphasizing functional strength integration after THA has the potential to substantially improve postoperative physical function by improving movement compensations with greater hip abductor strength and recruitment during function, providing greater pelvic control and movement quality. Therefore, the proposed investigation involves a randomized controlled trial to determine if an 8-week functional strength integration (FSI) program improves physical function and muscle performance more than control intervention (CON) in Veterans undergoing unilateral THA. The secondary goal is to determine if FSI improves movement compensations during functional activity (walking and stair climbing). Functional and biomechanical outcomes will be assessed pre-operatively (PRE) and at three postoperative time points: intervention mid-point, 4 weeks (POST1), intervention end-point, 8 weeks (POST2) (primary endpoint) and late recovery, 26 weeks (POST3).
STATEMENT A large increase in total hip arthroplasty (THA) surgeries is anticipated in the next two decades, yet innovative rehabilitation techniques are still needed to optimize long-term physical function. This study has high potential to change current rehabilitation practice for THA in Veterans because functional strength integration rehabilitation strategies can be easily implemented in clinical settings.