Impact On The Outcome Of Spinopelvic Relationship On Total Hip Arthroplasty

Background: Total hip arthroplasty (THA) is a highly successful procedure for end-stage hip arthritis; however, complications such as dislocation and instability persist. Increasing evidence highlights the role of spinopelvic dynamics in influencing acetabular orientation and postoperative stability. Conventional static guidelines for cup placement may not adequately address individual variations in spinopelvic mobility. Aim: To evaluate the impact of spinopelvic relationship on functional outcomes and stability following THA and to assess the effectiveness of individualised acetabular component positioning based on spinopelvic parameters. Methods: This prospective comparative study included 48 patients undergoing primary THA over 18 months. Patients were randomly assigned to Group A (conventional cup placement) and Group B (spinopelvic-guided cup placement). Preoperative and postoperative spinopelvic parameters, including difference in sacral slope (dSS) and pelvic-femoral angle (dPFA), were assessed on standing and sitting lateral radiographs. Functional outcomes were evaluated using the Harris Hip Score (HHS) at 6 weeks, 3 months, and 6 months. Complications, including dislocation, were recorded. Results: Baseline demographic and preoperative parameters were comparable between groups. Group B demonstrated significantly better functional outcomes, with higher mean HHS at all follow-up intervals (6 months: 90.37 vs 82.20), alongside improved stability. Dislocations occurred only in Group A (3 cases), while no dislocations were observed in Group B. Patients with abnormal spinopelvic mobility benefited most from modified acetabular positioning. Conclusion: Spinopelvic mobility significantly influences THA outcomes. Individualised acetabular component placement based on spinopelvic assessment improves functional outcomes and reduces the risk of dislocation compared to conventional techniques. Incorporating routine spinopelvic evaluation into preoperative planning may enhance surgical precision and patient outcomes.