Impact of preoperative spinopelvic risk factors on functional outcomes after total hip arthroplasty

Aims: This study aims to assess the functional outcomes of total hip arthroplasty (THA) in patients with pre-existing spinopelvic risk factors, hypothesizing that reduced spinal mobility and spinal deformities will result in poorer postoperative outcomes. Methods: )) ≥ 13°. Functional outcomes were measured using the Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) 12 months postoperatively. A mixture of both parametric and non-parametric statistical tests were used as required by the data, including Krusal-Wallis tests with Dunn's post-hoc testing, chi-squared tests, Mann-Whitney U tests, multiple linear regression, and propensity score matching. Results: Of the 825 THAs in 775 patients (mean age 64.57 years (SD 10.01), 50.55% female (n = 417)), 21.7% (179 patients) had one or more spinopelvic risk factors. The mean postoperative HOOS JR scores were 91.6 (SD 11.3) for patients without risk factors and 89.3 (SD 12.4) for those with at least one risk factor, with no clinically significant reduction in score (p = 0.125). However, patients with two or more risk factors had significantly lower HOOS-JR scores compared to those with no risk factors (p = 0.001). Multiple linear regression identified standing PT ≤ -10° as the only individual risk factor significantly associated with poorer functional outcomes (p = 0.029). Conclusion: While preoperative spinopelvic risk factors did not universally result in inferior functional outcomes, patients with multiple risk factors (two or more), particularly those with abnormal standing pelvic tilt, showed significantly lower postoperative HOOS-JR scores. These findings highlight the importance of comprehensive preoperative evaluation of spinopelvic parameters to optimize functional outcomes in THA.