Fixed-bearing versus mobile-bearing total knee arthroplasty: a prospective randomised, clinical and radiological study with mid-term results at 7 years. Mobile- versus fixed-bearing total knee arthroplasty: a prospective randomized controlled trial featuring 6-10-year follow-up. The John Insall Award: No Functional Advantage of a Mobile Bearing Posterior Stabilized TKA 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. One Year After Navigated Total Knee Replacement, No Clinically Relevant Difference Found Between Fixed Bearing and Mobile Bearing Knee Replacement in a Double-Blind Randomized Controlled Trial Gait analysis of fixed bearing and mobile bearing total knee prostheses during walking: do mobile bearings offer functional advantages? Fixed- versus Mobile-Bearing Total Knee Arthroplasty in Indian Patients Long-term comparison of mobile-bearing vs fixed-bearing 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. Fixed versus mobile weight-bearing prosthesis in total knee arthroplasty Staged bilateral mobile-bearing and fixed-bearing total knee arthroplasty in the same patients: a prospective comparison of a posterior-stabilized prosthesis Randomized controlled trial of radiographic and patient-assessed outcomes following fixed versus rotating platform total knee arthroplasty. Gait analysis and electromyography in fixed- and mobile-bearing total knee replacement: a prospective, comparative study Comparison of the tibiofemoral rotational alignment after mobile and fixed bearing total knee arthroplasty Fixed- vs mobile-bearing total knee arthroplasty: does it make a difference?--a prospective randomized study. [Fixed-bearing versus mobile-bearing total knee arthroplasty: a prospective randomized clinical and radiological study]. Clinical and radiological results of high flex total knee arthroplasty: a 5 year follow-up Relationship between joint gap difference and range of motion in total knee arthroplasty: a prospective randomised study between different platforms
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 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 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 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 Background : The mobile bearing design s have not yet been shown to improve clinical outcome of total knee arthroplasty ( TKA ) . In this prospect i ve r and omized study , we compared the short-term clinical results of a mobile bearing implant with those of the fixed bearing version of the same implant . Methods : We r and omized 100 knees into two double-blind groups who received either the fixed ( FB , 52 knees ) or the mobile bearing ( MB , 48 knees ) version of the same implant .  We used navigation to st and ardize the surgical technique . For up to one year , we recorded the Knee Society ( KSS ) and Oxford ( OXF ) scores . We performed an exploratory analysis of variance ( ANOVA ) to determine the influence of baseline scores as covariate and the extent of improvement in clinical outcome over time . Results : After one year , we did not detect any statistically significant difference between the two groups . The KSS scores differed by 2 points , the OXF scores by 1.1 points . Conclusion : Even with identical geometry of implant surfaces and a navigated surgical technique , first-year results do not support a preference for either a fixed or a mobile design BACKGROUND Limited previous findings have detailed biomechanical advantages following implantation with mobile bearing ( MB ) prostheses after total knee replacement ( TKR ) surgery during walking . The aim of this study was to compare three dimensional spatiotemporal , kinematic , and kinetic parameters during walking to examine whether MBs offer functional advantages over fixed bearing ( FB ) design s. METHODS Sixteen patients undergoing primary unilateral TKR surgery were r and omised to receive either a FB ( n=8 ) or MB ( n=8 ) total knee prosthesis .  Eight age and gender matched controls underwent the same protocol on one occasion . A 12 camera Vicon system integrated with four force plates was used . Patients were tested pre-surgery and nine months post-surgery . RESULTS No significant differences between FB and MB groups were found at any time point in the spatiotemporal parameters . The MB group was found to have a significantly reduced frontal plane knee range of motion ( ROM ) at pre-surgery than the FB group ( FB=14.92±4.02 ° ; MB=8.87±4.82 ° ) , with the difference not observed post-surgery . No further significant kinematic or kinetic differences were observed between FB and MB groups . Fixed bearing and MB groups both displayed spatiotemporal , kinematic , and kinetic differences when compared to controls . Fixed bearing and MB groups differed from controls in six and five parameters at nine months post-surgery , respectively . CONCLUSIONS No functional advantages were found in knees implanted with MB prostheses during walking , with both groups indicative of similar differences when compared to normal knee biomechanics following prosthesis implantation . LEVEL OF EVIDENCE Level II 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 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 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 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 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 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 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 Purpose The anatomical l and mark for the anteroposterior ( AP ) axis of the proximal tibia and its variability was investigated in order to determine whether a certain l and mark could be employed as a reference axis for the proximal tibia after the rotating platform mobile bearing and fixed bearing total knee arthroplasties ( TKAs ) . Methods Eighty primary osteoarthritic knees were r and omized to undergo either rotating platform mobile bearing ( Group A , n = 40 ) or fixed bearing ( Group B , n = 40 ) TKAs , and were followed up for 31 and 30 months , respectively . The AP axes were defined for the distal femur , proximal tibia , ankle , and each TKA component on the reconstructed CT scan and the angles between the distal femoral AP axis and those of each bone or component were estimated . Clinical and radiographic outcomes were evaluated during the follow up . Results A significant difference was seen between the preoperative and postoperative rotational position of the proximal tibia relative to the distal femur following rotating platform mobile bearing TKA ( P = 0.014 ) whereas no such difference was seen after fixed bearing TKA .  The mean postoperative alignment of the tibia differed between the two groups ( Group A : Group B = −2.9:0.2 , P = 0.010 ) and its variability was significantly greater in group A ( P < 0.001 ) . There were no differences in the clinical outcomes including range of motion , knee society score , function score , HSS , and WOMAC score as well as the mean postoperative coronal tibiofemoral alignment between the two groups . Conclusion The unpredictable change in the rotational axis of the tibia and its broad variability after rotating platform mobile bearing TKA may provide a warning against the use of a fixed l and mark for establishing tibial rotational alignment . Level of evidence Prospect i ve comparative study , Level II 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 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 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 The objective of this study was to investigate the range of motion ( ROM ) of the knee before and four years after total knee arthroplasty ( TKA ) with a mobile or fixed type of platform and to prospect ively evaluate whether there was a difference in ligament balance between the platform types . The subjects were 68 patients involving 76 joints . The mobile type was used in 31 joints and fixed type in 45 joints by employing a prospect i ve r and omised method . The passive maximum ROM was measured using a goniometer before and four years after surgery . Also , the intraoperative knee ligament balance was measured . The postoperative extension ROM was significantly improved after TKA using a mobile bearing type compared with that employing a fixed bearing type . In TKA using the former , the intraoperative gap difference was not related to the postoperative flexion angle of the knee . However , they were related in TKA using a fixed bearing type , with a positive correlation regarding the flexion gap
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 .