Unique Migration of a Septic Loosened Metal-on-metalCementless Total Hip Arthroplasty: A Case Report and Literature Review

INTRODUCTION: Total hip arthroplasty (THA) is one of the most successful and cost- effective surgical procedures developed during the last century. Although, chronic infection accompanied with granulomatous allergic reaction from Cobalt (Co),Chromium (Cr) debris after metal-on-metal (MoM) THA implantation can cause severe osteolysis, with subsequent loosening and migration of the implants. There are many cases with intrapelvic migration of these implants, however to best of our knowledge, there is no report of a complete horizontal migration (on frontal plane) of the whole THA prosthesis without disassembly accompanied with severe bone destruction. CASE REPORT: A 52-year-old female patient was admitted to the authors’ department with inability to weight bear. Because of bilateral developmental hip dysplasia (Type II, Hartofilakidis classification) she underwent THA bilaterally at another institution about 20 years ago. On admission, the initial plain roentgenogram of the hip was impressive, disclosing sclerotic, osteolytic lesions, associated with perforation of the lateral and medial cortices of the proximal femur, and migration to 90-degree horizontal position on the frontal plane of the whole prosthesis. Based on the preoperative planning, the implants were removed through a small medial longitudinal approach accompanied with lateral debridement. The patient denied revision surgery and the final result was a resection arthroplasty. CONCLUSION: THA is one of the most clinically successful surgical procedures, although inappropriate patient or implant selection for primary hip arthroplasty can lead to the necessity of complex revision surgery after late-diagnosed postoperative complications such as infection, loosening, and migration of the prosthesis. A well-designed preoperative plan is mandatory when handling such cases. Clinicians when faced with THA migration, rare or common, should definitely rule out the infection. Adverse reactions to metal debris (ARMD) can also lead to significant displacement of a hip prosthesis, although coexistence of metallosis and infection cannot be excluded in advance.