Association of spinopelvic mobility and osteosarcopenia with total hip arthroplasty outcomes.

Purpose: This study assessed the association of spinopelvic mobility and osteosarcopenia with the achievement of a patient-acceptable symptom state in patient-reported outcomes after total hip arthroplasty. Methods: This retrospective study included 244 patients who underwent primary total hip arthroplasty with a minimum follow-up of 24 months. Spinopelvic mobility was assessed using changes in sacral slope during postural transitions, classified as stiff (<10°), normal (10°-30°), or hypermobility (≥30°). Osteosarcopenia was defined by psoas muscle area on computed tomography and lumbar bone mineral density. Outcomes were assessed using the EuroQol 5-Dimension and the Hip Disability and Osteoarthritis Outcome Score-Joint Replacement. Multivariate logistic regression analysis was performed to identify predictors of a patient-acceptable symptom state achievement on the EuroQol 5-Dimension. Propensity score matching yielded 35 patients with limited mobility and 70 controls. Results: Physiological spinopelvic mobility (odds ratio 0.66, 95% confidence interval 0.56-0.78, Conclusion: Preoperative spinopelvic stiffness and osteosarcopenia independently predict poor functional recovery following total hip arthroplasty. This indicates the need for comprehensive preoperative assessments addressing both spinopelvic biomechanics and musculoskeletal health to optimise total hip arthroplasty strategies. Future research should explore tailored surgical approaches to improve outcomes in vulnerable populations, particularly those with impaired spinopelvic mobility and osteosarcopenia. Level of Evidence: Level III, retrospective cohort study.