title: No differences in clinical outcomes between fixed- and mobile-bearing computer-assisted total knee arthroplasties and no correlations between navigation data and clinical scores.
abstract: OBJECTIVE
  The theoretical advantages of mobile-bearing (MB) designs over the conventional fixed bearings (FBs) for total knee arthroplasty (TKA) have not been proved yet through clinical studies. The aim of the study was to test whether the MB design has advantages in terms of better clinical outcomes when compared to FB. Furthermore, the relationships between intra-operative obtained implant positioning data and the clinical scores were analysed.
  
  
  METHODS
  A total of 99 patients were randomized into the FB or the MB group. All patients received the same posterior cruciate retaining implants and were operated with the use of a computer-assisted navigation system. The clinical outcomes of both groups were compared pre-operatively, at 1 year, and at a mean follow-up time of 4 years after surgery.
  
  
  RESULTS
  The MB implants showed no advantages over the FB when comparing the Knee Society Scores, the Oxford Score, the range of movement (ROM) and pain intensity of the patients in both groups at 1 and 4 years after surgery. There were no relationships between the computer navigation data and the clinical scores.
  
  
  CONCLUSIONS
  In view of the 4-year results, there is no evidence to support the recommendation of one design over the other in terms of better clinical outcome scores, higher ROM or lower pain rates. Long-term follow-up results may be necessary, including survival rates. Further research comparing different TKA designs should also include standardized performance-based tests.
  
  
  METHODS
  Prospective study (Randomized controlled trial with adequate statistical power to detect differences), Level I.
authors.affiliation: Research Center of the Orthopedic and Joint Replacement Department, Schoen Klinik Hamburg Eilbek, Dehnhaide 120, 22081, Hamburg, Germany, cmarques@schoen-kliniken.de.
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Marques
authors.forename: Sandra
authors.initials: S
authors.lastname: Daniel
authors.forename: Anusch
authors.initials: A
authors.lastname: Sufi-Siavach
authors.forename: Frank
authors.initials: F
authors.lastname: Lampe
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D010147:Pain Measurement; D063868:Patient Outcome Assessment; D011446:Prospective Studies; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D025321:Surgery, Computer-Assisted