Complete 180° Rotatory Dislocation in a Mobile-Bearing Knee Prothesis

Abstract 

Dislocation of the rotator platform in mobile-bearing total knee arthroplasty is a well-documented, albeit uncommon, phenomenon. A review of the literature has revealed multiple case reports describing spin out to 90° or complete extrusion of the polyethylene component. Closed reduction may be attempted in the acute presentation followed by revision if instability persists. We present a case of a 57-year-old woman who had a partial rotatory subluxation of her polyethylene component and underwent closed reduction resulting in a full 180° spinout. To our knowledge, this has not been described in the literature and should be considered as a possibility after closed reduction attempts. She was treated successfully with open exploration and poly exchange using a larger component.

Keywords: mobile-bearing, dislocation, subluxation, polyethylene, knee arthroplasty