title: A comparative analysis between fixed bearing total knee arthroplasty (PFC Sigma) and rotating platform total knee arthroplasty (PFC-RP) with minimum 3-year follow-up.
abstract: BACKGROUND
  Since the introduction of mobile bearing total knee designs nearly 30 years back, many studies have been done to evaluate its long-term result. Comparison with fixed bearing designs has been done in the past, but the studies were confounded by variables such as disease, surgeon, bone quality, pain tolerance, etc. We attempt to eliminate these variables in this study.
  
  
  METHODS
  A total of 50 patients who had bilateral arthritis of the knee with similar deformity and pre-operative range of motion on both sides agreed to have one knee replaced with mobile bearing total knee design (PFC-RP) and the other with a fixed bearing design (PFC Sigma) were prospectively evaluated. Comparative analysis of both the designs was done at a mean follow-up of 40 months, minimizing patient, surgeon and observer related bias. Clinical and radiographic outcome, survival and complication rates were compared.
  
  
  RESULTS
  At a mean follow-up of 40 months (range 36-47 months), no benefit of mobile bearing (PFC-RP) over fixed bearing design (PFC Sigma) could be demonstrated with respect to Knee Society scores, pain scores, range of flexion, subject preference or patello-femoral complication rates. Radiographs showed no difference in prosthetic alignment. No patient required a revision surgery till last follow-up.
  
  
  CONCLUSIONS
  Our study demonstrated no advantage of the mobile-bearing arthroplasty over fixed bearing arthroplasty with regard to clinical results at short-term follow-up. However, longer follow-up is necessary to confirm whether these results are sustained.
authors.affiliation: Department of Orthopaedics, All India Institute of Medical Sciences, Room No. 5019, New Delhi 110029, India. akramjawed79@gmail.com
authors.forename: Akram
authors.initials: A
authors.lastname: Jawed
authors.forename: Vijay
authors.initials: V
authors.lastname: Kumar
authors.forename: R
authors.initials: R
authors.lastname: Malhotra
authors.forename: C S
authors.initials: CS
authors.lastname: Yadav
authors.forename: S
authors.initials: S
authors.lastname: Bhan
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D016009:Chi-Square Distribution; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000601:surgery*; D010147:Pain Measurement; D011183:Postoperative Complications; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular; D015996:Survival Rate; D016896:Treatment Outcome; D016474:Weight-Bearing