title: Rotaglide total knee arthroplasty: a long-term follow-up study.
abstract: BACKGROUND
  Mobile-bearing knee designs represent an alternative to conventional fixed-bearing implants in total knee arthroplasty. The purpose of this study was to determine the clinical results of a mobile-bearing knee implant.
  
  
  METHODS
  From 1990 to 1998, 326 primary consecutive mobile-bearing total knee prostheses were implanted in 260 patients who had a mean age and standard deviation of 66.7 ± 6.9 years. Femoral and tibial components were cemented in all knees, and the patella was resurfaced in 199 knees (61%). Patients were evaluated with the use of the Knee Society clinical rating system and radiographic examinations. Complications were noted, and survivorship of the prostheses was determined.
  
  
  RESULTS
  The mean follow-up period was 156 ± 27.3 months, with maximum follow-up at eighteen years. The mean Knee Society knee score improved from 32.4 ± 21.2 preoperatively to 92.6 ± 10.0 at the time of the last follow-up (p = 0.00), and the mean Knee Society functional score improved from 39.3 ± 18.7 preoperatively to 66.7 ± 18.6 at the time of the last follow-up (p = 0.00). Mean knee flexion improved from 92.3° ± 14.5° preoperatively to 112.1° ± 13.4° at the time of the last follow-up (p = 0.00). There were twenty-four (7.4%) knees that required revision. In eighteen (5.5%) knees, worn out or broken polyethylene was found and a polyethylene-only exchange was done. Six knees (1.8%) were fully revised. The survival rate was 0.96 (95% confidence interval, 0.93 to 0.98) at ten years and 0.87 (95% confidence interval, 0.79 to 0.93) at eighteen years.
  
  
  CONCLUSIONS
  A fully congruent, mobile-bearing total knee prosthesis had excellent survivorship during the ten to eighteen-year follow-up interval.
authors.affiliation: Department of Orthopaedic Surgery, Hippokrateion General Hospital, 48 Konstantinoupoleos Street, Thessaloniki 54639, Greece. sterimet@otenet.gr
authors.forename: Stergios R
authors.initials: SR
authors.lastname: Metsovitis
authors.forename: Avraam L
authors.initials: AL
authors.lastname: Ploumis
authors.forename: Paraskevas T
authors.initials: PT
authors.lastname: Chantzidis
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Terzidis
authors.forename: Anastasios G
authors.initials: AG
authors.lastname: Christodoulou
authors.forename: Christos G
authors.initials: CG
authors.lastname: Dimitriou
authors.forename: Athanasios C
authors.initials: AC
authors.lastname: Tsakonas
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007719:Knee Joint / Q000000981:diagnostic imaging; D007720:Knee Prosthesis / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D011475:Prosthesis Failure; D011859:Radiography