Study Design: Retrospective cohort study. Objectives: The interactions between hip osteoarthritis (OA) and spinal malalignment are poorly understood. The purpose of this study was to assess the influence of total hip arthroplasty (THA) on standing spinopelvic alignment. Methods: In this retrospective cohort study, patients undergoing THA for OA with pre-and postoperative full-body radiographs were included. Standing spinopelvic parameters were measured. Contralateral hip was graded on the Kellgren-Lawrence scale. Pre-and postoperative alignment parameters were compared by paired t-test. The severity of preoperative thoracolumbar deformity was measured using TPA. Linear regression was performed to assess the impact of preoperative TPA and changes in spinal alignment. Patients were separated into low and high TPA (<20 or >/=20 deg) and change in parameters were compared between groups by t-test. Similarly, the influence of K-L grade, age, and PI were also tested. Results: 95 patients were included (mean age 58.6 yrs, BMI 28.7 kg/m2, 48.2% F). Follow-up radiographs were performed at mean 220 days. Overall, the following significant changes were found from pre-to postoperative: SPT (14.2 vs. 16.1, P = 0.021), CL (−8.9 vs. −5.3, P = .001), TS-CL (18.2 vs. 20.5, P = .037) and SVA (42.6 vs. 32.1, P = .004). Preoperative TPA was significantly associated with the change in PI-LL, SVA, and TPA. High TPA patients significantly decreased SVA more than low TPA patients. There was no significant impact of contralateral hip OA, PI, or age on change in alignment parameters. Conclusion: Spinopelvic alignment changes after THA, evident by a reduction in SVA. Preoperative spinal sagittal deformity impacts this change. Level of evidence: III.
The impact of capsular repair on the risk for dislocation after revision total hip arthroplasty – a retrospective cohort-study of 259 cases
