Severe Metallosis-Induced Osteolysis and Polyethylene Liner Dissociation as a Cause of Total Knee Replacement Failure

Introduction: Metallosis is a rare but recognized complication following total knee replacement (TKR). It is characterized by metallic particle deposition within periprosthetic tissue, triggering chronic inflammation, progressive osteolysis, and implant loosening. Case Report: A 63-year-old female with bilateral TKRs, performed 12 and 15 years earlier, presented with pain, swelling, and restricted flexion of the right knee following a fall. She had a history of recurrent instability and locking for 3 years. Imaging revealed extensive osteolysis, polyethylene liner dissociation, and loosening of the tibial component. She underwent one-stage revision with implant removal, synovectomy, and implantation of a constrained modular revision prosthesis. Postoperatively, she showed stable function without recurrence. Conclusion: Although uncommon in knee arthroplasty, metallosis can lead to catastrophic implant failure if undetected. Timely recognition and revision surgery with thorough synovectomy are essential to restore function and prevent further bone loss.