Polyethylene liner dislocation of fixed-bearing medial oxinium unicompartmental arthroplasty with severe metallosis.

The case of an atraumatic dislocation of a fixed bearing in a medial unicompartmental arthroplasty with an oxinium femoral component is presented. A review of the literature pertaining to knee arthroplasty locking mechanisms is discussed. Potential modes of locking mechanisms failure are reviewed including the recognition of such failures in the clinical setting. This is the first report of a dislocated fixed-bearing medial oxinium unicompartmental arthroplasty and consequent metal arthrogram.