title: Influence of joint area design on tibial component migration: comparison among a fixed symmetrical, asymmetrical, and moveable bearing.
abstract: Fifty-four knees (50 patients) were allocated to three different tibial polyethylene inserts (standard/rotating platform/FS1000) in the Freeman-Samuelson (Finsbury Orthopaedics Ltd, Surrey, United Kingdom) total knee arthroplasty. The FS1000 design has a spherical medial and a roller-in-trough configuration laterally. Radiostereometric examinations were done postoperatively and after 3, 12, and 24 months. The median migration of the metal-backing and the Hospital for Special Surgery scores did not differ between the three groups. At 2 years, the median external/ internal displacements for the rotating platforms were 2.8 degrees and 0.2 degrees, respectively (rotating platforms versus standard inserts/rotating platforms versus FS1000: P < .0005). Longitudinal rotations above the detection limits for radiostereometry were observed in some of the fixed implants (standard and FS1000 designs), indicating conditions for backside wear.
authors.affiliation: Dept of Orthopedics, Göteborg University, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Uvehammer
authors.forename: J
authors.initials: J
authors.lastname: Kärrholm
authors.forename: L
authors.initials: L
authors.lastname: Carlsson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular; D013977:Tibia / Q000000981:diagnostic imaging / Q000601:surgery
chemical_list: D020959:Polyethylene