Metallosis After Oxinium Total Knee Arthroplasty in a Patient With Rheumatoid Arthritis: A Case Report

Abstract

Metallosis is a late uncommon complication of knee arthroplasties due to prosthetic loosening or component displacement. Oxinium prosthesis used to have components that attempted and proved to decrease prosthetic wear and consequent metallosis in the past. However, new studies showed that a combination of a shallow anterior tab snap-fit locking mechanism and thin dovetail lips make it susceptible to polyethylene dislocation and prosthesis loosening. The following case report show metallosis development in a 69-year-old female patient with a 20-year history of stage IV left gonarthrosis (Kellgren and Lawrence classification) who underwent a total knee arthroplasty (TKA) with a high-flex PS Genesis II prosthesis (Smith & Nephew, Hertfordshire, UK). We discuss the role of the material and her rheumatoid arthritis background in orthopedic mechanical failure. It is crucial that designers focus on the improvement of locking mechanisms and polyethylene properties.

Extensive Metallosis in a Primary Knee Arthroplasty as a Result of Polyethylene Wear: Is It Avoidable?

“…Another cause of PE failure contributing to metallosis is the design of knee prostheses [ 7 ]. The metal components of the knee prosthesis are stainless steel composed of cobalt-chromium-molybdenum (CoCrMo) alloy.…”

“…The CoCrMo alloy has a large surface area exposed to the surrounding tissue, increasing the risk of metal debris and ion deposition in the surrounding tissue, resulting in an increased risk of metallosis [ 8 ]. Furthermore, with 15% of the population experiencing metal allergies, there is an increased risk of PE failure due to its potential to induce type 4 hypersensitivity reactions [ 7 ]. The introduction of ceramic nitride-based coatings such as titanium nitride (TiN) and titanium niobium nitride (TiNbN) offer a protective layer over the prosthetic components, solidifying the metal and minimising the release of metal debris into the surrounding tissue [ 8 ].…”

“…Additionally, TiN components are suitable for patients with metal allergies, showing almost identical clinical and radiological results compared to those without metal allergies who received conventional implants [ 12 ]. In a rare case, a 64-year-old man developed metallosis four years after his TKA despite having ceramic-surfaced oxidized zirconium implants [ 7 ]. These studies highlight that although current evidence suggests limited clinical significance of coated versus non-coated knee prosthesis, in terms of survival rate, cost-effectiveness, and post-implant complications, further studies are necessary to explore the specific risk of metallosis between the two techniques and determine if ceramic coatings can effectively lower the risk of developing metallosis.…”

First Italian Experience with the Oxinium Metal-Backed Fixed-Bearing Medial Journey II Unicompartmental Knee System: Promising Short-Term Outcomes of 145 Cases

“…Although these studies indicate that oxidized zirconium could extend implant life and reduce the need for revision, there have been reports of catastrophic failure in patients with UKA secondary to the dislocation of fixed polyethylene bearings and metallosis [ 34 , 75 , 76 ] or with TKA [ 77 , 78 , 79 ].…”

Two-stage revision knee arthroplasty for metallosis in a patient with rheumatoid arthritis: A case report

“…In addition, metallosis after TKA following falls in rheumatoid arthritis patients has been reported. 18 The polyethylene liner failure induced metallosis in the short term, suggesting that it may be related to increased inflammation in the background of rheumatoid arthritis.…”