Giant Pseudotumour Following Ceramic on Polyethylene Total Hip Replacement

Abstract

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.

Keywords: Ankylosing spondylitis; Ceramic-on-polyethylene; Metal reaction; Osteolysis; Pseudotumour.

Fig. 1

a – Immediate postoperative image following the index surgery done in 2012; b - Diffuse osteolysis noted at the medial calcar and the proximal one-third femur shaft of the right hip, seven years after the index surgery; c & d – Magnetic Resonance Images showing mixed signal intensity with erosion of the intertrochanteric region of the right femur, lateral and medial cortex of the upper shaft of the proximal femur. The lesion was also extending into the intermuscular planes of the adductor group and inferior gluteal intermuscular planes

Fig. 2

a & b – Anteroposterior and lateral radiographs showing the osteolytic lesion over the right hip had progressed to involve the right iliac wing, the supra and infra-acetabular regions and the whole of proximal femur extending to the middle one third shaft of the femur. c & d - showing Magnetic Resonance Imaging was repeated and the size had increased and eroding the right hip joint involving the posterior and anterior lip of the acetabulum and the supra-acetabular part of the right ilium. The lesion completely distorted the anatomy of proximal muscles of the thigh along with the intermuscular compartments, with fluid collections extending into the fascio-muscular and subcutaneous planes

Fig. 3

a – Clinical image showing the extent of the tumour; b – Intraoperative image showing the extensive osteolysis of the proximal femur exposing the implant. c – Dissected specimen with the implant in-situ showing extensive metal reaction at the trunnion and necrotic tissue involving all the muscle compartments. d - Acetabular cup and liner intact with minimal metal reaction