Total hip arthroplasty for ankylosed hip in young patients: a report of two cases using anterior and posterior approaches

Introduction and importance: Total hip arthroplasty (THA) in ankylosed hips is technically challenging due to distorted anatomy, loss of joint space, and difficulty with surgical exposure. The optimal surgical approach remains controversial, particularly in young patients with severe deformities. Presentation of case: We report two young patients with hip ankylosis who underwent THA using different approaches based on deformity characteristics. A 20-year-old female with bilateral hip ankylosis in external rotation underwent THA via the direct anterior approach, with the Harris Hip Score improving from 0.39% to 53.4%. A 14-year-old male with a fixed flexion-adduction deformity and limb shortening underwent THA via the posterior approach, with the Harris Hip Score improving from 45.35% to 85.25%. Clinical discussion: These cases demonstrate that the selection of surgical approach should be individualized based on the deformity pattern and intraoperative exposure requirements. The anterior approach may be advantageous for selected patients, whereas the posterior approach provides better visualization in complex deformities. Conclusion: THA can significantly improve function and quality of life in young patients with ankylosed hips. Both anterior and posterior approaches can achieve favorable outcomes when selected based on deformity characteristics. Careful preoperative assessment and individualized approach selection are essential to optimize functional outcomes.