title: Comparison of ultra-congruent mobile- and fixed-bearing navigation-assisted total knee arthroplasty with minimum 5-year follow-up.
abstract: OBJECTIVE
  The purpose of this study was to compare the midterm outcomes between fixed and mobile ultra-congruent (UC) bearings in total knee arthroplasty (TKA).
  
  
  METHODS
  This is a retrospective matched-pairs case-control study of patients who underwent primary navigation-assisted TKA with a minimum 5-year follow-up. A total of 182 cases involved the fixed UC bearing system as Group 1 and 101 cases involved mobile UC bearing system group as Group 2. After 1:1 matching, 73 knees in each group were enrolled. Clinical and radiographic outcomes were evaluated.
  
  
  RESULTS
  The overall survival was 143 of 146 cases (97.9 %) at final follow-up, and 72 of 73 cases (96.3 %) in Group 1 and 71 of 73 cases (95.8 %) in Group 2 at final follow-up based on an endpoint of revision surgery. The reasons of revision TKA were periprosthetic fracture in Group 1, infection and bearing dislocation in Group 2. There was no statistical difference in Hospital for Special Surgery (HSS) scores, Knee Society Scores (KSS), WOMAC index score evaluations between groups.
  
  
  CONCLUSIONS
  This study demonstrated that the fixed-bearing UC prosthesis could provide satisfactory performance compared with that of the mobile-bearing UC prosthesis with minimum 5-year follow-up. The fixed-bearing UC prosthesis could be considered in navigation-assisted TKA with theoretical advantages of UC design.
  
  
  METHODS
  IV.
authors.affiliation: Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, 102 Heukseok-ro, Dongjak-ku, Seoul, 156-755, South Korea.
authors.forename: Seong Hwan
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, 102 Heukseok-ro, Dongjak-ku, Seoul, 156-755, South Korea.
authors.forename: Jung-Won
authors.initials: JW
authors.lastname: Lim
authors.affiliation: Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, 102 Heukseok-ro, Dongjak-ku, Seoul, 156-755, South Korea.
authors.forename: Young-Bong
authors.initials: YB
authors.lastname: Ko
authors.affiliation: Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, 102 Heukseok-ro, Dongjak-ku, Seoul, 156-755, South Korea.
authors.forename: Min-Gu
authors.initials: MG
authors.lastname: Song
authors.affiliation: Department of Orthopaedic Surgery, Chung-Ang University College of Medicine, 102 Heukseok-ro, Dongjak-ku, Seoul, 156-755, South Korea. gustinolhj@nate.com.
authors.forename: Han-Jun
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D057068:Periprosthetic Fractures / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Fixed bearing; Mobile bearing; Navigation system; Total knee arthroplasty; Ultra-congruent bearing