Rehabilitation-Specific Predictors of Pain Intensity and Physical Activity Levels in Individuals With Acetabular Dysplasia 6 Months After Periacetabular Osteotomy

Introduction: Individuals with acetabular dysplasia often report hip joint instability, pain, and poor hip-related function. Periacetabular osteotomy (PAO) is a surgical procedure that aims to reposition the acetabulum to improve joint congruency and improve pain and function. We aimed to examine the influence of presurgery clinical measures on functional recovery following PAO and the associations among clinical outcomes after PAO. Methods: We screened 49 potential participants, 28 were enrolled, and 23 completed both study visits (pre-PAO and 6 months post-PAO). We evaluated dynamometer-measured hip and thigh strength, loading patterns during a squat and countermovement jump (CMJ), pain intensity, and device-measured physical activity (PA) levels (light, moderate-to-vigorous PA [MVPA], and daily steps). We used linear regression models to examine the influence of muscle strength (peak torque; limb symmetry index [LSI]) and loading patterns before PAO on pain intensity and PA levels in individuals 6 months following PAO. Additionally, we used Pearson correlation coefficient to examine cross-sectional associations among all variables 6 months following PAO. Results: Lower extremity muscle strength and loading patterns during the squat and CMJ before PAO did not predict pain intensity or device-measured PA levels in individuals 6 months following PAO (p > 0.05). Six months following PAO, higher knee extensor LSI was associated with higher time spent in MVPA (r = 0.56; p = 0.016), higher hip abductor LSI was associated with both lower pain (r = 0.50; p = 0.036) and higher involved limb loading during the squat task (r = 0.59; p = 0.010). Lastly, higher hip flexor LSI was associated with higher CMJ takeoff involved limb loading (r = 0.52; p = 0.021) and higher involved hip extensor strength was associated with higher CMJ landing involved limb loading (r = 0.56; p = 0.012). Conclusion: Six months after PAO, higher hip and thigh muscle strength and strength symmetry were associated with lower pain, higher PA levels, and greater normalized limb loading during dynamic movement tasks.