Library Subscription: Guest
Begell Digital Portal Begell Digital Library eBooks Journals References & Proceedings Research Collections
Journal of Long-Term Effects of Medical Implants
SJR: 0.332 SNIP: 0.491 CiteScore™: 0.89

ISSN Print: 1050-6934
ISSN Online: 1940-4379

Journal of Long-Term Effects of Medical Implants

DOI: 10.1615/JLongTermEffMedImplants.2014010563
pages 147-150

Severe Metallosis Following Polyethylene Dislocation in a Mobile-Bearing Medial Unicompartmental Knee Replacement

Alexandros P. Apostolopoulos
Trauma and Orthopaedics Department, East Surrey Hospital, Surrey and Sussex Healthcare NHS Trust, United Kingdom
Ilias Katsougrakis
Trauma and Orthopaedic Department, Ealing Hospital NHS Trust, London North West Healthcare, UK
Rafik Fanous
Department of Trauma & Orthopaedics, Ealing Hospital NHS Trust, London, United Kingdom
Andrew Harrison
Department of Trauma & Orthopaedics, Ealing Hospital NHS Trust, London, United Kingdom
Enrique Saavedra
Department of Trauma & Orthopaedics, Ealing Hospital NHS Trust, London, United Kingdom

ABSTRACT

Metallosis is a rare cause of failure after unicompartmental knee replacement (UKR) and has only previously been reported when there has been abnormal metal-on-metal contact. We present a case report of a 67-year-old woman who was admitted to our department with a 5-month history of a painful right knee. There was no history of trauma and her past medical history was unremarkable. She had undergone a primary mobile bearing medial UKR of her right knee 5 years ago. During the preceding 5 months, the patient complained that the knee was becoming unstable, was painful, and was making frequent clicking noises associated with metallic friction. Plain radiographs of the right knee showed dislocation of the polyethylene bearing and the patient was taken to the operating room for revision of the implant. Intraoperatively, severe evidence of metallosis was found in the periprosthetic soft tissues. The tibial component was found to be loose and the polyethylene bearing was dislocated posteriorly. The implants were revised. Postoperative recovery was uneventful. Microscopic examination revealed findings consistent with metallosis. At the latest follow-up, the patient had a good clinical and radiological outcome. In conclusion, such a complication of UKR requires early diagnosis and treatment as it can result in implant loosening and metallosis.