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.
Subject(s)
Arthroplasty, Replacement, Knee/instrumentation , Knee Dislocation/diagnostic imaging , Knee Prosthesis , Prosthesis Failure , Rotation , Female , Humans , Joint Instability/etiology , Joint Instability/surgery , Knee Dislocation/complications , Knee Dislocation/surgery , Knee Joint/diagnostic imaging , Knee Joint/surgery , Middle Aged , Osteoarthritis, Knee/surgery , Polyethylene , Radiography , Reoperation , Treatment OutcomeABSTRACT
One hundred seventy-one primary total hip arthroplasties were evaluated in a prospective, randomized study. Ninety-five involved a metal-backed cup with an all-metal liner and 76 involved a metal-backed polyethylene cup that was used as the control. All were implanted with an S-ROM cementless femoral component with a 28 mm head. The mean follow-up period was 3.7 years (range, 3.0-5.7). The average postoperative Harris hip score was 95.4 (range, 65-100) for the metal-on-metal group and 96.1 (range, 65-100) for the metal-on-polyethylene group. Radiographic results were not statistically different between the 2 groups. Early results show the metal-on-metal articulation has been successful to date and justify continued clinical use.
