Functional outcomes of total hip arthroplasty in ankylosing and non-ankylosing hip conditions: A pilot study

Objectives: Ankylosing spondylitis (AS) primarily affects the pelvis and spine, with peripheral arthritis and enthesitis being common manifestations. When debilitating hip degeneration occurs, total hip arthroplasty (THA) offers significant pain relief with functional improvement in patients with AS. This study aimed to compare the clinical outcomes following THA between patients with ankylosing hips and those with non-ankylosing hip conditions. Methods: We retrospectively reviewed data from January 2018 to June 2022 at Prof. Dr. R. Soeharso Orthopaedic Hospital, Surakarta. The Harris Hip Score (HHS) was used to assess outcomes in 23 patients with ankylosing hips and 23 patients with non-ankylosing hips undergoing THA. A modified HHS was applied, substituting two traditional components (range of motion and deformity) with assessments focused on return to professional activity and sexual function. Post-operative outcomes were assessed at 6 months to evaluate functional recovery. Results: At final follow-up, patients with non-ankylosing hips demonstrated significantly higher HHS compared to the ankylosing group. Functional improvement was observed in both groups postoperatively. The ankylosing group’s average HHS improved from 55.65 preoperatively to 76 postoperatively, while the non-ankylosing group improved from 55.65 to 87.95. The difference in post-operative scores between groups was statistically significant ( P < 0.05). Conclusion: THA provides considerable pain relief and enhances hip mobility in patients with AS, yielding favorable functional outcomes as measured by the HHS. Nonetheless, patients without ankylosing hip pathology experience superior functional recovery post-THA.