Diagnostic Dilemma: Unusual Post-replacement Hip Pain Following Trauma Leading to Metallosis - A Case Report.

Introduction: Metallosis, characterized by the collection of metallic debris in periarticular tissues, is primarily associated with metal-on-metal bearings in hip arthroplasty. This report presents a rare case of metallosis after metal-on-polyethylene (MoP) total hip arthroplasty (THA), highlighting diagnostic challenges and management strategies. Metallosis following MoP arthroplasty is extremely rare, with only a limited number of documented cases in the literature.

Case report: A 70-year-old man presented with post-traumatic hip pain and instability 6 years after an uncemented MoP THA. Radiographs revealed a fractured acetabular cup with metal fragments and displacement of the femoral head. A computed tomography scan confirmed liner failure, cup breakage, and radiodense opacities around the joint. Given the post-traumatic presentation and the risk of heterotopic ossification, the patient underwent revision surgery. Revision surgery involved acetabular component exchange, and clinical follow-up indicated satisfactory outcomes.

Conclusion: This case highlights the atypical presentation of metallosis following MoP THA, emphasizing the significance of early diagnosis and awareness for optimal patient outcomes.