Metallosis following Knee Arthroplasty: A Histological and Immunohistochemical Study

Abstract

Metallosis represents a rare and severe complication of knee replacement surgery. It is caused by the infiltration and accumulation of metallic debris into the peri-prosthetic structures, deriving from friction between metallic prosthetic components. In knee arthroplasty, this event generally occurs as a result of polyethylene wear of the tibial or metal-back patellar component. The real incidence of metallosis is still unknown, although it seems to be more frequent in hip than in knee arthroplasty. The metallic debris induces a massive release of cytokines from inflammatory cells, making a revision necessary whenever osteolysis and loosening of the prosthesis occur. We report four patients who underwent revision of their knee arthroplasty because of severe metallosis. In one of these patients, polyethylene wear had determined friction between the metal-back patellar component and the anterior portion of the femoral component. In the remaining three cases, metallosis was caused by friction between the femoral and tibial prosthetic metal surfaces, resulting from full-thickness wear of the ti~ial polyethylene. T lymphocytes were activated by metal particles present in periprosthetic membranes. In all patients, one-stage revision was necessary, with rapid pain disappearance and a complete functional recovery of the knee joint. Metallosis represents a rare and dangerous complication of total knee arthroplasty (TKA). It is characterized by the infiltration and accumulation of metal debris into the peri-prosthetic structures, including bone and soft tissues (1-3). The debris derives from friction among metal prosthetic surfaces, mainly due to the wear of the tibial and/or the metal-backed patellar polyethylene component. Metallosis seems to be more frequent in hip replacement, being the result of the metal-on-metal coupling (4). The exact incidence of metallosis following TKA is unknown. Chang et al. reported an overall 5.3% incidence of metallosis in 418 total hip arthroplasties (5); Ollivere et al. reported a 3.1% rate of metallosis-related failure at five years in 463 primary metal-on-metal hip resurfacing arthroplasties (6). Metallosis has also been described in shoulder arthroplasty (7-13).The presence of intra-articular metallic debris can be detected by x-ray imaging, this condition being an indication for early revision (1,3,5). Furthermore, metallosis can cause peri-prosthetic osteolysis, as the consequence of the release of cytokines from the inflammatory cells, inducing pain and implant loosening (14-19): this condition makes implant revision essential in order to prevent further bone loss.All orthopaedic implants are heading towards

Oxidized Zirconium Total Knee Arthroplasty Implant Failure in a Patient With Knee Instability

“…Schiavone Panni et al. [ 18 ] reported on four patients who developed metallosis, 1 unicompartmental knee replacement (UKA) and 3 TKAs, and noted that osteolysis results from the immune response to metallic particles and release of cytokines. In their series, one case of metallosis was the result of friction between the metal-back patellar component and anterior femoral component, which is prevented with the use of an all-polyethylene patellar component.…”

A Unique Case of Extra-articular Extravasation of Metal Into the Lower Leg Resulting From Oxidized Zirconium Wear Particles From Total Knee Arthroplasty

“…In knees, metallosis typically occurs late when there is catastrophic wear of the polyethylene. Metallosis in TKA tends to result most commonly from the use of metal-backed patellar implants or because of wear of the tibial polyethylene [8,14,15]. Although there is documentation of intra-articular metal debris after knee replacement [14,16,17], there is limited documentation of extra-articular extravasation of metal down the lower extremity compartments.…”

A Rare Complication of Arthroplasty: Metallosis

“…Widespread lymphocytic, histiocytic and plasmacytic infiltration around metal debris, foreign body giant cells, metal particles and extracellular metal deposits, as well as intracytoplasmic debris in giant cells can be seen in its histology. Inflammatory T lymphocytes can infiltrate synovium, causing synovial hyperplasia (5).…”