Meta-analyses showed no clinical ly relevant differences in terms of revision rates , clinical outcome scores or patient-reported outcome measures between MB and FB TKRs .
It appears that theoretical assumptions of superiority of MB over FB TKR are not borne out in clinical practice
Mobile-bearing ( MB ) total knee replacement ( TKR ) was introduced to reduce the risk of aseptic loosening and wear of polyethylene inserts .
However , no consistent clinical advantages of mobile- over fixed-bearing ( FB ) TKR have been found .
In this study we evaluated whether mobile bearings have an advantage over fixed bearings with regard to revision rates and clinical outcome scores .
Furthermore , we determined which modifying variables affected the outcome .
Rotating Platform Knees Did Not Improve Patellar Tracking: A Prospective, Randomized Study of 240 Primary Total Knee Arthroplasties
Renewed interest in mobile-bearing total knee replacement design s has been generated by the concept of self alignment and the suggestion that those design s can accommo date small mismatches in the rotational position of the tibial and femoral components . Self alignment might improve patellar tracking , decrease the prevalence of lateral retinacular release and postoperative patellar tilt or subluxation , improve knee flexion , and improve patellofemoral function during daily activities such as stair climbing . This prospect i ve r and omized study of 240 patients used a single posterior-stabilized femoral component  and included three groups of 80 patients : an  all-polyethylene group , a modular metal-backed group , and a rotating platform tibia group . The prevalence of lateral retinacular release was 3.8 % in each group . The prevalence of patellar tilt was 5 % ( all-polyethylene group ) , 7 % ( modular metal-backed group ) , and 11 % ( rotating platform group ) . Preoperative motion was not significantly different and both the 3-month flexion ( 112 ° , 110 ° , and 108 ° ) and 1-year flexion ( 116 ° , 117 ° , and 115 ° ) were not significantly different among the all-polyethylene , modular metal-backed , and rotating platform groups , respectively . Preoperative stair climbing scores were not significantly different and both the 3-month ( 38 , 41 , and 35 points ) and 1-year ( 44 , 46 , and 42 points ) scores were not significantly different . In this prospect i ve r and omized study , the rotating platform knee design did not decrease the prevalence of lateral retinacular release or patellar tilt or subluxation and did not increase knee flexion or improve stair climbing ability at 3 months or at 1 year postoperatively when compared with a posterior-stabilized , fixed-bearing knee
Meta-analyses showed no clinical ly relevant differences in terms of revision rates , clinical outcome scores or patient-reported outcome measures between MB and FB TKRs .
It appears that theoretical assumptions of superiority of MB over FB TKR are not borne out in clinical practice
Mobile-bearing ( MB ) total knee replacement ( TKR ) was introduced to reduce the risk of aseptic loosening and wear of polyethylene inserts .
However , no consistent clinical advantages of mobile- over fixed-bearing ( FB ) TKR have been found .
In this study we evaluated whether mobile bearings have an advantage over fixed bearings with regard to revision rates and clinical outcome scores .
Furthermore , we determined which modifying variables affected the outcome .