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

With an increasing number of joint replacements and the evolution of orthopaedic implants and hardware, there is increased occurrence and awareness of metal-related sensitivity. This has resulted in the development of devices using a variety of different materials to coat the implant. One popular option is to cover the metallic surface with a ceramic. One commercially available ceramic-coated prosthesis is coated with oxidized zirconium, with the trade name Oxinium. Although pseudotumor and metallosis resulting from ceramic joint arthroplasty implants have been documented, there is limited information on the occurrence of metallosis resulting from ceramic-coated knee implants. The purpose of this case report is to discuss a potential differential diagnosis for lower leg mass after total knee arthroplasty and to present a novel case of catastrophic failure of an Oxinium-coated total knee prosthesis (Smith and Nephew) that resulted in metallosis with extra-articular extravasation along the extensor digitorum longus tendon.