Similarly , no difference was revealed between the groups for radiological outcomes or general health results .
Controversy exists regarding the clinical and radiological differences in outcomes between  fixed-bearing ( FB ) and mobile-bearing ( MB ) total knee arthroplasties ( TKAs ) at the mid- or long-term follow-up .
We therefore conducted a meta- analysis and systematic review of r and omized controlled trials ( RCTs ) that have evaluated FB and MB TKAs .
The John Insall Award: No Functional Advantage of a Mobile Bearing Posterior Stabilized TKA
Background Mobile bearing ( MB ) total knee design has been advocated as a means to enhance the functional characteristics and decrease the wear rates of condylar total knee arthroplasty ( TKA ) . However , it is unclear if these design s achieve these goals . Questions / purpose sWe asked whether function of patients or survivorship would be greater or complications would be lesser in groups of patients with MB compared with fixed bearing ( FB ) TKA .  We also sought to describe retrieval findings . Methods We r and omized 507 primary TKAs in 416 eligible patients to receive MB ( n = 252 ) or FB ( n = 255 ) devices from November 2001 to August 2007 ( Investigational Device Exemption G000180 , Clinical Trials.gov registration number NCT00946075 ) . Patients were blinded to treatment allocation . WOMAC Index , SF-12 Health Survey , knee range of motion , and Knee Society scores were collected and compared preoperatively and at 6 , 12 , and 24 months postoperatively . We recorded device failures and complications until October 2009 . Kaplan-Meier survivorship was compared using the log rank test . Twelve retrieved MB devices underwent pathologic analysis . The minimum postoperative time was 2.2 years ( mean , 5.9 years ; range , 2.2–7.9 years ) . Results We found no differences in mean clinical assessment scores or mean score changes from baseline at any postoperative interval through 2 postoperative years . Nineteen of the 252 MB and 13 of the 255 FB knees had undergone revision of any component . Estimated survival at 6 postoperative years was similar for the two devices : 90.1 % ( 95 % confidence interval [ CI ] , 84.1–93.9 ) for MB and 94.2 % ( 95 % CI , 90.1–96.6 ) for FB . Two MB and no FB tibial components were revised for loosening . There was one case of MB insert dislocation . Retrieved MB devices demonstrated no unexpected wear or mechanical device failures . Conclusion We found no evidence of functional advantage of the MB design . Survivorship was similar , although the study is limited by short duration of followup . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence
Similarly , no difference was revealed between the groups for radiological outcomes or general health results .
Controversy exists regarding the clinical and radiological differences in outcomes between  fixed-bearing ( FB ) and mobile-bearing ( MB ) total knee arthroplasties ( TKAs ) at the mid- or long-term follow-up .
We therefore conducted a meta- analysis and systematic review of r and omized controlled trials ( RCTs ) that have evaluated FB and MB TKAs .