Giant Pseudotumour Following Ceramic on Polyethylene Total Hip Replacement.

Introduction: Metal reaction and pseudotumor formation are very rare complications following ceramic on polyethylene total hip replacement. Pseudotumors have been described in the case of metal on polyethylene as well as in metal on ceramic interfaces. We report the largest pseudotumor formation to be observed after a thorough literature review following ceramic on polyethylene total hip replacement in a case of ankylosing spondylitis and chronic kidney disease. Case report: The patient had reported 7 years following the index surgery with an uncemented total hip arthroplasty and presented with osteolytic changes of the right proximal femur and later was lost to follow-up due to the COVID-19 pandemic. The patient returned again 2 years later presenting with the pseudotumor. Owing to the presence of extensive osteolysis with gross necrotic muscle mass around the proximal one-third of femur and since bone stock was available, reconstruction of the hip joint was not considered and hence a right side hind-quarter amputation was performed. Conclusion: This immune reaction was possibly exacerbated due to the underlying ankylosing spondylitis and chronic kidney disease requires more stringent follow up protocols and early intervention. It is, thereby, necessary to evaluate patients with serial radiography following total hip replacement, especially those with conditions which could accelerate the immune responses to the metal. This could potentially avoid an amputation and allow for reconstruction of the hip with appropriate immunomodulation.