Metallosis, a Rare Long-Term Complication in a Total Hip Arthroplasty: A Case Report and Literature Review

Metallosis and metal-induced synovitis are well-documented complications associated with metal-backed polyethylene joint prostheses, extensively covered in orthopedic surgery literature. However, the radiological aspects of these complications are less frequently discussed in the literature. There is growing recognition of local and systemic adverse events associated with the release of metal ions and nanoparticles from hip arthroplasty components. Adverse local tissue reactions to metal ion debris can manifest as periprosthetic solid and cystic masses, termed pseudotumors. These pseudotumors can cause pain, swelling, extensive destruction of surrounding hip soft tissues, and compression syndromes affecting neurovascular, gastrointestinal, and genitourinary structures. We present the case of a 50-year-old patient with a history of end-stage chronic renal failure on hemodialysis, who underwent a total left hip arthroplasty 20 years ago. The patient developed a progressively enlarging mass in the left hip, which evolved to include loss of function and increasing inflammatory joint pain. A CT scan and MRI of the left hip were performed, showing radiological signs of metallosis characterized by osteolysis with amorphous increased densities in the periprothetic soft tissues. This case illustrates the importance of radiological findings in the diagnosis and management of rare complications of hip prostheses.