Neglected Bipolar Hemiarthroplasty Dislocation in a Young Adult with Superior Acetabular Wall Defect - A Case Report.

Introduction: Developmental dysplasia of the hip imposes significant challenges in hip arthroplasty due to altered hip anatomy, deficient bone stock, and abnormal biomechanics. Bipolar hemiarthroplasty performed in such hips carries a high risk of migration, loosening, or dislocation. Case Report: We present the case of a 23-year-old female with failed bipolar hemiarthroplasty performed for femoral neck fracture, complicated by unrecognized acetabular dysplasia. She presented with pain, difficulty in ambulation, inability to sit cross-legged or squat, and complete restriction of hip movements. Radiographs showed proximal migration with posterior dislocation of the bipolar prosthesis and acetabular changes. After ruling out infection, she underwent implant removal followed by cemented total hip arthroplasty with acetabular reconstruction using tricortical iliac crest autograft. Results: At 1-year follow-up, she achieved pain-free ambulation with graft incorporation on radiographs, stable acetabular fixation, and no evidence of infection or loosening. Conclusion: In young patients with failed hemiarthroplasty and underlying dysplasia, acetabular roof reconstruction with autologous tricortical graft combined with cemented THA provides a cost-effective, biologically favorable, and bone-preserving solution.