Total Hip Arthroplasty in Bilateral Ankylosed Hip by Direct Anterior Approach: A Case Report with Technical Tips.

INTRODUCTION: Bony ankylosis of the hip results in profound functional disability and poses significant challenges during total hip arthroplasty (THA), especially when associated with spinal ankylosis. Altered anatomy, severe soft-tissue contractures, fixed deformities, and disturbed spinopelvic mechanics complicate patient positioning, anesthetic management, and component placement and increase the risk of post-operative instability. Although THA has demonstrated favorable functional outcomes in ankylosed hips, limited literature highlights the role of the direct anterior approach (DAA) in patients with concomitant spinal fusion. We report a rare case of bilateral hip and spinal ankylosis managed successfully using DAA THA. CASE REPORT: A 40-year-old female, completely bedridden for 10 years, presented with the inability to sit, stand, or perform activities of daily living due to long-standing stiffness of multiple joints. Clinical examination revealed complete ankylosis of both hips and the spine, with a 30° fixed flexion deformity of the left hip. Radiographs confirmed bony ankylosis of both hips and the entire spine. The Harris Hip Score was 0. Staged bilateral THA was performed using the DAA in the supine position under general anesthesia. Intraoperative fluoroscopy facilitated controlled acetabular reaming and accurate component positioning. Dual mobility cups were used to mitigate instability risk related to absent spinopelvic motion. Early post-operative mobilization was initiated. At 1-year follow-up, the patient achieved independent sitting and assisted ambulation, with the Harris Hip Score improving to 80 and no episodes of dislocation or major complications. CONCLUSION: DAA THA is a feasible and effective option in patients with ankylosed hips and spine. Supine positioning and fluoroscopic guidance enhance surgical accuracy and stability, enabling significant functional recovery.