Mobile- versus fixed-bearing total knee arthroplasty: a prospective randomized controlled trial featuring 6-10-year follow-up. Fixed-bearing versus mobile-bearing total knee arthroplasty: a prospective randomised, clinical and radiological study with mid-term results at 7 years. Differences in long-term fixation between mobile-bearing and fixed-bearing knee prostheses at ten to 12 years' follow-up: a single-blinded randomised controlled radiostereometric trial. Fixed versus mobile weight-bearing prosthesis in total knee arthroplasty Randomized controlled trial of radiographic and patient-assessed outcomes following fixed versus rotating platform total knee arthroplasty. A prospective randomised study comparing rotating platform and fixed bearing total knee arthroplasty in a cruciate substituting design--outcomes at two year follow-up. Staged bilateral mobile-bearing and fixed-bearing total knee arthroplasty in the same patients: a prospective comparison of a posterior-stabilized prosthesis Fixed- versus Mobile-Bearing Total Knee Arthroplasty in Indian Patients Comparison of mobile-bearing and fixed-bearing total knee arthroplasty: a prospective randomized study. Long-term comparison of mobile-bearing vs fixed-bearing total knee arthroplasty. The John Insall Award: No Functional Advantage of a Mobile Bearing Posterior Stabilized TKA [Fixed-bearing versus mobile-bearing total knee arthroplasty: a prospective randomized clinical and radiological study]. Fixed- vs mobile-bearing total knee arthroplasty: does it make a difference?--a prospective randomized study. Mobile vs. fixed meniscal bearing in total knee replacement: a randomised radiostereometric study. Gait analysis and electromyography in fixed- and mobile-bearing total knee replacement: a prospective, comparative study Greater satisfaction in older patients with a mobile-bearing compared with fixed-bearing total knee arthroplasty. Clinical and radiological results of high flex total knee arthroplasty: a 5 year follow-up
OBJECTIVE The purpose of this study was to compare long-term clinical and radiographic outcomes of mobile- ( MB ) and fixed-bearing ( FB ) total knee arthroplasties ( TKA ) . METHODS A r and omized controlled study was conducted to compare the clinical and radiographic outcomes of MB and FB prostheses in 93 consecutive patients who underwent primary TKA for knee osteoarthritis . Mean follow-up of the patients was 100.9 months in the MB group ( range : 78 - 121 months ) and 93.7 months ( range : 78 - 120 months ) in the FB group . The clinical results were grade d according to the Knee Society Knee Score ( KSKS ) and the Knee Society Functional Score ( KSFS ) . Secondary outcomes included pain , patellofemoral joint function , quality of life ( QOL ) , and radiologic outcomes ( Knee Society 's roentgenographic evaluation system ) . RESULTS Although there was significant improvement in both groups , there were no significant differences between the groups with respect to mean KSFS and radiologic outcomes . However , mean pain score of the MB group was significantly higher than that of the FB group ( 48.83±0.62 vs 47.39±0.86 , respectively , p=0.011 ) , and mean KSKS was significantly higher than that of the FB group ( 93.5±6.2 vs 89.7±6.9 , respectively , p=0.007 ) . CONCLUSION TKA clinical results were satisfactory in both the MB and FB groups . KSKS and pain scores were significantly better in the MB than in the FB group . However , no differences were found in other assessment s. Thus , we conclude that the best design is the one with which the surgeon is most comfortable and most able to implant reproducibly Mobile-bearing ( MB ) total knee arthroplasty ( TKA ) was developed as an alternative to the established fixed-bearing ( FB ) design because of theoretical advantages . Short-term studies comparing these design s have not shown any differences in clinical and radiographic results . We compared the results at 7 years of a r and omised study of patients undergoing TKA using either a FB or a MB variant of the same prosthesis . Fifty-two patients ( 52 knees ) with an average age of 70 years received a FB posterior-stabilized prosthesis , and 50 patients ( 52 knees ) with an average age of 72 years , a MB prosthesis .  All implants were cemented and the patella was routinely resurfaced . Preoperatively , there were no differences between the two groups , and surgical procedure and postoperative protocol were the same for both . At an average follow-up of 7.1 years , no significant differences of FB over MB design could be demonstrated with respect to the American Knee Society score ( AKSS ) , pain score , a question naire of general health ( SF-12 score ) , range of motion ( ROM ) , or complication rates . Radiographs showed no significant difference in prosthetic alignment or evidence of loosening . Two knees with a MB design required reoperation , one for persistent joint stiffness and another to treat septic loosening . One patient with a MB prosthesis with signs of tibial component loosening was asymptomatic . We conclude that at mid-term follow-up there is no evidence to prove the superiority of MB over FB TKA with regard to the clinical and radiographic results This single-blinded r and omised controlled trial investigated whether one design of mobile-bearing ( MB ) total knee replacement ( TKR ) has any advantage over a fixed-bearing ( FB ) design on long-term fixation as measured by radiostereometry . The amount of wear underneath the mobile bearing was also evaluated . A series of 42 knees was r and omised to MB or FB tibial components with appropriate polyethylene inserts and followed for between ten and 12 years , or until the death of the patient . The polyethylene in the MB group was superior in that it was gamma-irradiated in inert gas and was calcium-stearate free ; the polyethylene in the FB group was gamma-irradiated in air and contained calcium stearate . In theory this should be advantageous to the wear rate of the MB group . At final follow-up the overall mean migration was 0.75 mm ( SD 0.76 ) in the MB group and 0.66 mm ( SD 0.4 ) in the FB group , with the FB group demonstrating more posterior tilt and the MB group more internal rotation . In the FB group there was one revision for aseptic loosening , but none in the MB group . There were no significant differences in clinical or radiological scores . For the MB group , the mean linear wear rate on the under-surface was 0.026 mm/year ( SD 0.014 ) . This was significantly smaller than the wear rate of 0.11 mm/year ( SD 0.06 ) in the MB between femur and polyethylene ( p < 0.001 ) . Nevertheless , even in a best-case setting the mobile bearings of this TKR design had no apparent advantage in terms of fixation over the FB knee prosthesis at ten to 12 years . The wear underneath the mobile bearing was small and is unlikely to be clinical ly relevant Purpose This study was design ed to compare clinical , radiological , and general health results of two prostheses ( mobile vs. fixed weight-bearing devices ) that are used in total knee arthroplasty with a 5-year follow-up . Methods This r and omized controlled study was conducted from 2004 to 2010 in the Department of Orthopedic Surgery at two university hospitals in Isfahan , Iran . Three hundred patients with expected primary total knee arthroplasty ( TKA ) without severe deformity ( a fixed varus or valgus deformity greater than 20 ° ) received fixed weight-bearing ( n = 150 ) or mobile weight-bearing ( n = 150 ) devices . Clinical , radiological , and quality of life outcomes were compared between the two groups at six-month intervals for the first year , after which the comparisons were made annually for the next 4 years . Results Both groups had similar baseline characteristics . Although there was significant improvement in both groups , there was no significant difference between the groups with regard to the means of the Knee Society Scores , which were 92 ( SD : 12.1 ) for the fixed weight-bearing device and 93 ( SD : 14.2 ) for the mobile weight-bearing device ( n.s . ) at the final follow-up point . Radiographs showed that there was no significant difference in prosthetic alignment and no evidence of loosening . After TKA , the SF-36 score increased in both groups , but there was no statistical difference between the groups in quality of life at the final follow-up ( 62 ( 12.2 ) vs. 64 ( 14.3 ) , n.s . ) . There was no revision after 5 years . Conclusions In terms of clinical , radiological or general health outcomes for people who underwent TKA , the results of this study showed no clear advantage of mobile weight-bearing over the fixed weight-bearing prosthesis at the five-year follow-up . Level of evidence This prospect ively blinded r and omized controlled study evaluated the difference in the functional and radiological outcomes in patients who received a press-fit condylar Sigma cemented cruciate-substituting total knee arthroplasty with either a rotating platform ( RP ) or a fixed bearing ( FB ) .  There were 51 joints in 49 patients : 24 joints in the RP group ( mean follow-up , 43 months ) and 27 joints in the FB group ( mean follow-up , 40 months ) . At baseline , there was no significant difference in age , body mass index , preoperative diagnosis , Charnley class , range of motion , clinical and functional scores , between the RP and FB groups . At mid-term follow up both the RP and FB give equivalent results , but patients with the RP tended to have a higher activity level score BACKGROUND Fixed bearing ( FB ) total knee replacement is a well established technique against which new techniques must be compared . Mobile bearing ( MB ) prostheses , in theory , reduce polyethylene wear but the literature is yet to provide evidence that they are superior in terms of function or long-term survivorship . In addition there has been no comparison of patella resurfacing on the outcome of either design . The aims of this r and omised prospect i ve study were firstly to determine whether a mobile bearing prosthesis produced better clinical outcome and range of motion at two year follow-up and secondly to assess the effect of patella resurfacing on the outcomes of both types of bearing design . METHODS Three hundred fifty-two patients were r and omised into receiving either a PFC Sigma © cruciate sacrificing total knee arthroplasty either with a mobile bearing or a fixed bearing  , with a sub-r and omisation to either patella resurfacing or patella retention . All patients participated with st and ard clinical outcome measures and had their range of motion measured both pre-operatively and at follow-up . RESULTS The mobile bearing TKR design had no impact on range of motion ; Oxford Knee Score and American Knee Society knee and function scores when compared to its fixed bearing equivalent . CONCLUSIONS At two year follow-up there was no difference between the PFC Sigma © fixed and mobile bearing design s. With no clinical difference between the cohorts , we can not recommend one design over the other . Long term benefits , particularly with regards to polyethylene wear , may yet be demonstrated . Level of evidence --1B Mobile-bearing total knee arthroplasty ( TKA ) has several theoretical advantages over fixed-bearing TKA . We conducted a prospect i ve r and omized trial to compare the results of mobile-bearing and fixed-bearing posterior-stabilized TKA in the same patients using the same femoral component design of a mobile-bearing prosthesis in one knee and a fixed-bearing prosthesis in the other knee in 25 patients with osteoarthritis . The mean follow-up was 40 months . No significant differences were found in the mobile-bearing and fixed-bearing knees in terms of clinical and radiographic results . No osteolysis , loosening , or revision occurred . One knee with a mobile-bearing prosthesis had a dislocation of the rotating bearing ; however , spontaneous reduction occurred and the dislocation did not recur . Satisfactory early results can be achieved in both mobile-bearing and fixed-bearing knees . We could not demonstrate an advantage of a mobile-bearing TKA Purpose . To compare the mid-term clinical outcomes in Indian patients after total knee arthroplasty ( TKA ) using a fixed- or mobile-bearing prosthesis . Methods . 120 consecutive patients ( 50 men and 70 women ) aged 55 to 76 ( mean , 63 ) years who had arthritis of the knee with similar deformity and range of motion were r and omised to undergo TKA using a fixed- or mobile-bearing prosthesis .  Patients with mediolateral instability and infective arthritis were excluded .  Knee Society knee and functional scores , range of motion , and the presence of flexion contracture were assessed . Results . The mean follow-up duration was 3.5 ( range , 1–4.6 ) years . The mid-term outcome of the 2 groups was comparable . One patient with a mobile-bearing prosthesis had recurrent dislocation at postoperative week 2 , owing to iatrogenic medial collateral ligament injury . Conclusion . Long-term studies of both functional and radiological outcomes are needed to determine the indications for fixed- versus mobile-bearing prostheses The purpose of this prospect i ve r and omized study was to compare the postoperative recovery and early results of 2 groups of patients undergoing total knee arthroplasty : 107 patients received an established fixed-bearing posterior-stabilized prosthesis ( Legacy Posterior Stabilized [ LPS ] ) , and 103 patients the meniscal-bearing prosthesis ( Meniscal Bearing Knee [ MBK ] ) .  Surgical procedures were the same for both groups except for posterior cruciate ligament management , which was sacrificed in the LPS group and spared but completely released from the tibia in the MBK group . At an average follow-up of 36 months , knee , function , and patellar scores were comparable in both groups . The LPS group showed a significantly higher maximum flexion than the MBK group ( 112 degrees vs 108 degrees ) . Using a fixed-bearing or a mobile-bearing design did not seem to influence the short-term recovery and early results after knee arthroplasty . Key words : total knee arthroplasty , mobile bearing , knee prosthesis , meniscal-bearing knee , posterior stabilized , prospect i ve r and omized Few published reports have been published regarding a comparison of the long-term outcomes between mobile- ( MB ) and fixed-bearing component design s for knee arthroplasty . The minimum 10-year clinical and radiologic follow-up of an unselected consecutive series of 89 patients ( 107 knees ) who were r and omized to have one of these different design s for primary arthroplasty was done . Twenty-six patients ( 30 knees ) who had a fixed-bearing design and 24 patients ( 33 knees ) who had an MB prosthesis were available for follow-up . Two MB knees were revised for aseptic loosening of a tibial component in one and femoral component fracture in the other . In patients who did not have revision surgery , there were no differences between the groups with respect to mean Knee Society scores , knee flexion , or pain scores 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 PURPOSE OF THE STUDY Mobile-bearing total knee arthroplasty has become increasingly popular over the last few years since this option presents several theoretical advantages compared with the fixed-bearing models . The clinical advantage remains to be demonstrated . We therefore conducted a prospect i ve r and omized trial to ascertain the potential benefits . MATERIAL AND METHODS This study included patients treated by three senior orthopedic surgeons . Each group included 52 prostheses in 52 patients in the fixed-bearing group and 50 patients in the mobile-bearing group . The per- and postoperative protocol s were the same for both groups . Implants were cemented in all cases and patellae were resurfaced . The SF-12 , the Knee Society Score ( KSS ) , the Hospital of Special Surgery score ( HSS ) and pain and joint motion were noted before and after surgery . RESULTS Among the 104 prostheses implanted , 100 were review ed at mean follow-up of 36 months ( range 24 - 41 ) . One patient in the fixed-bearing group died six months after surgery from an unrelated cause . Three patients were lost to follow-up : one in the fixed-bearing group and two in the mobile-bearing group . There was no difference between groups for the SF-12 , KSS , HSS , pain and joint motion measured postoperatively . Postoperative femorotibial alignment was one degree varus on average in the fixed-bearing group and zero degree in the mobile-bearing group . At last follow-up , there were no radiological signs of prosthesis loosening . One patient in the fixed-bearing group developed a deep venous thrombosis , complicated by pulmonary embolism . Two of the mobile-bearing prostheses were revised , one for patellar fracture caused by a bicycle accident and one for prosthesis infection in a patient with endocarditis 1.5 years after implantation . DISCUSSION The clinical results were similar for the two groups in terms of function , pain , general status and complications . The outcome at 36 months was considered excellent or good in 90 % of the fixed-bearing group and 88 % in the mobile-bearing group . This study did not reveal any difference between the two groups regarding maximal flexion and anterior knee pain , two parameters which would theoretically show short-term improvement with the mobile bearing . Mid- and long-term follow will be required to confirm these findings and to determine the survival of these two types of implants The purpose of this prospect i ve , r and omized study was to compare the early clinical and functional results of primary total knee arthroplasty using a fixed-bearing ( FB ) and a rotating-platform ( RP ) prosthesis .  Outcomes including range of motion ( ROM ) , Knee Society Score , Western Ontario MacMaster ( WOMAC ) , and Short Form-36 ( SF-36 ) were measured preoperatively and at 6 weeks , 3 months , 6 months , 1 year , and 2 years . Radiographic analysis was performed . There were 72 FB and 68 RP knees . The RP group had a greater ROM at 6 weeks and 1 year . This difference was not statistically significant at 2 years . There were no differences in the ROM at any other period . There were no significant differences in Knee Society Score , Short Form-36 , or Western Ontario MacMaster scores at any period . No clinical ly significant differences were noted in the radiographic analysis . The use of a FB or RP design did not affect the early functional outcomes after total knee arthroplasty 52 knees scheduled for a total knee arthroplasty were r and omised to either a fixed or a mobile polyethylene bearing . The design was identical in all parts . The knee systems used were the Rotaglide Total Knee System ( RTK ) and the Nuffield Total Knee System ( NTK ) , both from the same manufacturer ( Corin Medical Ltd. , UK ) . All knees implanted were uncemented . The patients were followed for 2 years clinical ly and with radiostereometric analyses to assess migration over time and inducible displacement of the tibial component . Separate analysis of the mobility of the tibial insert in the knees with a mobile bearing was also made . The migration measured with RSA between the 1st and 2nd year expressed as maximum total point motion ( MTPM ) might predict the risk of loosening of the implant . There were no differences between the groups regarding clinical outcome ( HSS Knee score ) , migration or inducible displacement during the 2 years follow-up . The movement between the tibial tray and the mobile meniscal insert expressed as maximum total point motion ( MTPM ) was 6.8+/-3.3 mm at the 1st year follow-up Purpose The theoretical superiority of mobile-bearing total knee arthroplasties ( TKAs ) has not yet been proven in clinical studies . The aim of the current study was to compare and to analyse in a patient population that had received either a fixed or a mobile TKA differences in gait analysis electromyography and clinical scores . Methods In a prospect i ve , r and omized , patient- and observer-blinded clinical study , 33 patients with primary osteoarthritis of the knee were included . All patients received a Genesis II total knee replacement . Sixteen patients received a mobile  and 17 a  fixed-bearing cruciate retaining Genesis II TKA .  Clinical and quality -of-life scores , electromyography and gait analysis were applied preoperatively and postoperatively with a follow-up of 24 months . Results In both groups , improvements from pre- to postoperative were detected . whereas the results of gait analysis and electromyography did not show any differences . The results from the clinical and the quality -of-life scores improved from pre- to postoperative , while the Knee Society Score showed a superiority of the mobile-bearing group ( mean 159 ± 28 ) over the fixed-bearing group ( mean 134 ± 41 ) . Conclusion No functional advantage of mobile over fixed-bearing TKA was detected , although the mobile-bearing group had better clinical results for which a reason could not be found . These results only apply to cruciate retaining mobile-bearing TKA with a bearing which allows both rotation and anteroposterior translation . Level of evidence Prospect i ve comparative study , Level II A prospect i ve , r and omized , controlled , double-blind trial was performed to compare outcomes between 61 mobile- and 58 fixed-bearing primary TKAs in patients aged 70 years or older . At last follow-up , no difference was found for Knee Society score . The mobile-bearing group had greater knee flexion at 3 and 6 months , but this was similar at 2 years . The patient satisfaction was better in the mobile-bearing group than in fixed-bearing group , with respect to Knee Society functional score , Western Ontario MacMasters University score , Short-Form 12 score , and visual analog scale score . A multivariate analysis confirmed that the only independent factors predictive of postoperative quality of life were early postoperative flexion . We believe that better perception and satisfaction with mobile-bearing in older patients was due to the earlier regain of their knee flexion . Our results justify the use of mobile-bearing design in the older population Introduction In a prospect i ve r and omized study , we compared the results after implantation of the mobile bearing high flex TKA with a fixed bearing posterior stabilized TKA in 60 patients ( 30 patients each group ) . Method We evaluated the hospital for special surgery-score ( HSS ) and different radiological parameters preoperatively , as well as 3 months , 3 and 5 years postoperatively . Result Three months postoperatively , the high flex group showed better results in scores for pain , ROM ( 122.5 ° vs. 107.33 ° ) , as well as in the overall HSS ( 87.21 vs. 82.68 points ) . Three and 5 years postoperatively , there were no differences between both the groups in all scores , but the HSS is still increasing . Conclusion The theoretical advantages of the mobile bearing knee prostheses were reflected in the clinical results , only partly and temporarily
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 .