title: Fixed versus mobile weight-bearing prosthesis in total knee arthroplasty Mobile-bearing prosthesis did not improve mid-term clinical results of total knee arthroplasty 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 Functional outcome of PFC Sigma fixed and rotating-platform total knee arthroplasty. A prospective randomised controlled trial Functional performance of mobile versus fixed bearing total knee prostheses: a randomised controlled trial Mobile-bearing insert translational and rotational kinematics in a PCL-retaining total knee arthroplasty. Clinical and radiological results of high flex total knee arthroplasty: a 5 year follow-up No difference in ROM and knee function between mobile and floating platforms in TKA Randomized clinical trial of rotating-platform and fixed-bearing total knee arthroplasty: no clinically detectable differences at five years. The John Insall Award: No Functional Advantage of a Mobile Bearing Posterior Stabilized TKA Fixed versus rotating platform total knee arthroplasty: a prospective, randomized, single-blind study. Relationship between joint gap difference and range of motion in total knee arthroplasty: a prospective randomised study between different platforms Comparison of Fixed-Bearing and Mobile-Bearing Total Knee Arthroplasties [Fixed-bearing versus mobile-bearing total knee arthroplasty: a prospective randomized clinical and radiological study]. Fixed-bearing versus mobile-bearing total knee arthroplasty: a prospective randomised, clinical and radiological study with mid-term results at 7 years. Fixed- vs mobile-bearing total knee arthroplasty: does it make a difference?--a prospective randomized study. A randomised controlled clinical trial and gait analysis of fixed- and mobile-bearing total knee replacements with a five-year follow-up. [Knee arthroplasty. Mobile- and fixed-bearing design].
abstract: 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 A prospect i ve study was performed to compare the clinical and radiological results of mobile- and fixed-bearing total knee arthroplasty  with specific attention to rotational alignment and range of motion . Sixty-one knees were assigned to total knee arthroplasty with either the NexGen LPS Flex fixed-bearing or with the NexGen LPS Flex mobile-bearing prosthesis . Postoperatively , knees were compared with regard to range of motion , clinical score , and radiographic findings . Rotational alignment of the femoral and tibial components was evaluated by computed tomography . The median follow-up period was 5.9 years ( range 2.1–8.8 years ) . Median postoperative Knee Society scores were 99 points ( 68–100 ) for the fixed-bearing group and 100 points ( 66–100 ) for the mobile-bearing group ( n.s . ) . The median postoperative flexion angles of 120 ° ( 90 ° –150 ° ) for the fixed-bearing group and 125 ° ( 90 ° –145 ° ) for the mobile-bearing group were not significantly different from each other ( n.s . ) . No knee required revision surgery due to wear of polyethylene or loosening of the component in either group . Computed tomography showed that 11 knees had rotational mismatches of more than 10 ° between the femoral and tibial components , but no significant difference was found in the postoperative extension and flexion angles or in the clinical score between the two treatment groups . Using the identical design for both fixed- and mobile-bearing prostheses , this prospect i ve , r and omized study did not show any clinical advantages of the mobile-bearing knee . Analysis of rotational alignment by CT scan did not reveal a particular advantage of the self-aligning mechanism of mobile-bearing implants 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 The aim of this study was to determine whether there is a difference in functional outcome between the PFC Sigma fixed-bearing and rotating-platform total knee replacement systems .  One hundred twenty patients were r and omised to receive either a fixed-bearing or rotating-platform PFC Sigma total knee replacement .  Range of movement ( ROM ) , Oxford knee score ( OKS ) and Knee Society score ( KSS ) were assessed independently before and one year after surgery . Weight-bearing X-rays were taken immediately and one year post surgery to determine the incidence of osteolysis and loosening . At a mean follow-up of 13.4 months there was no statistically significant difference in mean ROM , OKS and KSS between the two groups . There was no evidence of osteolysis or loosening in either of the groups and no revision for infection or implant failure . This study shows that there is no statistically significant difference in functional outcome between the two types of implants at short-term follow-up Purpose The primary goal of this study was to assess the difference in active flexion between patients with a mobile versus a fixed bearing , cruciate retaining , and total knee arthroplasty .  The study was design ed as a r and omised controlled multi-centre trial . Methods Participants were assigned to interventions by using block-stratified , r and om allocation . Outcome parameters were active flexion , passive flexion , and Knee Society Score ( KSS ) . Outcome parameters were assessed preoperatively and at 3 , 6 , and 12 months postoperatively by an independent nurse . Results Ninety-two patients from one centre were included , 46 in each group . Active flexion was comparable for the two groups , 99.9 ° for the mobile bearing group and 101 ° for the fixed bearing group with a baseline controlled difference of 1.0 ( 95 % CI −3.9 to 5.8 , n.s . ) . The Clinical KSS was comparable between the two bearing groups ( Mobile 90.0 vs. fixed 92.4 , n.s . ) . The functional KSS showed a difference that was attributable to the stair climbing subscore , which showed a difference in favour of the fixed bearing design between preoperative and 3 months ( 7.3 point difference ; 95 % CI 2.3–12.5 ; P = 0.005 ) as well as 12 months ( 4.8 point difference ; 95 % CI 0.1–9.6 ; P = 0.045 ) . Conclusions There were no short-term differences in active flexion  between fixed bearing and mobile bearing total knee arthroplasty . Level of evidence INTRODUCTION  Total knee prostheses  with a mobile-bearing insert were developed to provide nonconstrained joint range of motion while reducing friction forces . The purpose of this study was , based on weightbearing X-rays , to evaluate the mobility of the polyethylene tibial insert in relation to the femoral and tibial components . We studied the results of a cementless total knee arthroplasty ( TKA ) retaining the posterior cruciate ligament ( PCL ) , with a mobile-bearing platform in rotation and anteroposterior translation ( Innex Anterior-Posterior Glide , Zimmer ) with a mean 23-month follow-up duration after surgery . HYPOTHESIS Both anterior-posterior tibiofemoral translation and intraprosthetic axial rotation occur between the mobile polyethylene insert and the tibial endplate . MATERIAL AND METHOD In a series of 51 primary TKA , the three-dimensional ( 3D ) kinematics of the femoral , tibial , and mobile insert components were determined using a computerized matching system between the prosthetic 3D models and the radiographic images of the implants on three lateral follow-up weightbearing knee X-rays : films were taken in full extension , at 45 degrees flexion , and at maximum flexion . RESULTS There was a statistically significant increase in the internal rotation of the mobile tray with flexion , ( up to a mean -3+/-3 degrees between the femoral box and the mobile tray [ p<0.0001 ] and up to a mean -5+/-7 degrees between the tibial tray and the mobile tray [ p<0.0001 ] ) . The mobile tray did not translate in relation to the tibial endplate from extension to 45 degrees flexion ( 0+/-2 mm [ range : -5 to 6 mm ] ) . However , from 45 degrees to maximum flexion , a statistically significant mean 1+/-2 mm ( range : -2 to 9 mm ) of anterior translation ( p<0.0001 ) was found . DISCUSSION The extent of insert mobility varies from one study to another . Some have reported relatively limited mobility stemming from a superior surface that is not highly congruent , ( thus allowing anterior-posterior and mediolateral translation through gliding of the femur in contact with the insert ) . Other studies have reported mobile-bearing tray mobility in relation to the tibial endplate and minimal rotation at the femoral component level . In this series of PCL retaining TKA with a mobile-bearing platform , the mobile-bearing platform showed a progressive increase in internal rotation during flexion . Most of this rotational mobility occurred between the mobile platform and the tibial endplate , confirming our hypothesis . However , with flexion , the femoral component increased its mobility relatively to the platform . During flexion , an anterior-posterior translation occurred between the femoral implant and the tibial insert , and between the tibial insert and the tibial endplate , but the direction of the mobile tibial insert translation remained unpredictable with this nonconstrained implant design used . LEVEL OF EVIDENCE Level IV . Prospect i ve non-controlled therapeutic study 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 Purpose The purpose of this study was to determine whether the floating platforms ( FP ) were superior to rotating platforms ( RP ) in computer-navigated total knee  arthroplasty ( TKA ) comparing the range of motion ( ROM ) as well as clinical and subjective function of the knee . Methods This retrospective non-r and omized single-centre cohort study includes 255 patients with a primary implanted computer-navigated e.motion ™ ( Aesculap B. Braun ) TKA system , implanted because of clinical and radiological verified gonarthrosis . In 129 patients , the FP platform was implanted  , and in 126 patients , the RP platform . As statistical procedures for differences between inlay type RP/FP in ROM and Knee Society Score ( KSS ) after 3- and 24-month follow-up , an analysis of covariance ( with risk factors gender , age , BMI , preoperative ROM and preoperative KSS ) was performed . Results Although preoperative ROM and knee society function score ( KSS partII ) were significantly higher in the FP group before surgery , there was no significant difference between RP and FP  in ROM and KSS at 3- and 24-month follow-up . Conclusion The FP platform design did not have an advantage in ROM as well as in clinical and subjective knee function compared with the RP platform in computer-navigated TKA neither in early follow-up examinations at 3 months postoperatively nor at long-time follow-up at 24 months postoperatively . Level of evidence Therapeutic study , Level III BACKGROUND For some surgeons , rotating-platform total knee design s are an intellectually appealing option to use for total knee arthroplasty because of the contention that they can self-align and accommo date small mismatches in the rotational position of the tibial and femoral components . We carried out a r and omized clinical trial to determine if a posterior-stabilized , rotating-platform knee design provided better maximum knee flexion , better function , or better durability at five years of follow-up when compared with a fixed-bearing design . METHODS This r and omized clinical trial of 240 primary total knee arthroplasties involved a single type of distal femoral implant ( posterior-stabilized ) and three different types of tibial implant ( all-polyethylene fixed-bearing , modular-metal-backed fixed-bearing , and rotating-platform ) . The three tibial implant groups were balanced dynamically with a computerized r and omization process that accounted for patient age , sex , and body mass index ; surgeon ; and implant type . Patients returned for examination and radiographs at three months , one year , two years , and five years postoperatively . RESULTS Knee range of motion was not significantly different among the all-polyethylene , modular-metal-backed , and rotating-platform tibial component groups at two years ( mean , 111 ° , 111 ° , and 110 ° , respectively ) or five years ( mean , 110 ° , 109 ° , and 109 ° , respectively ) . Function , as measured with Knee Society scores , was not significantly different among the all-polyethylene , modular-metal-backed , and rotating-platform groups at two years ( mean , 90 , 91 , and 91 points , respectively ) or five years ( mean , 88 , 89 , and 88 points , respectively ) . Stair-climbing scores were not significantly different among the three groups at two years ( mean , 39 , 40 , and 39 points , respectively ) or five years ( mean , 37 , 40 , and 36 points , respectively ) . There were four revisions : one in the all-polyethylene group ( patellar fracture ) , two in the modular-metal-backed group ( aseptic loosening ) , and one in the rotating-platform group ( deep infection ) . CONCLUSIONS In this r and omized clinical trial , the rotating-platform total knee design was reliable and durable but did not provide better maximum knee flexion , better function , or better durability at five years postoperatively when compared with a posterior-stabilized , fixed-bearing design incorporating either an all-polyethylene or a modular-metal-backed tibial component 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 The purpose of this r and omized , single-blind clinical trial was to compare a rotating platform ( RP ) total knee arthroplasty to a fixed-bearing ( FB ) total knee arthroplasty . Ninety-five knees in 69 patients were implanted by 2 surgeons . There were no significant differences in the preoperative demographics . At a minimum of 2-year follow-up , clinical outcomes and complication rates were similar , with the exception that the RP group had significantly better stair-climbing scores ( P = .04 ) . Postoperative range of motion was equally good in both groups ( FB knees , 1 ° -125 ° ; RP knees , 1 - 126 ° ) . There were no bearing dislocations in the RP group . In conclusion , this RP design performs at least as well as the FB version , and the RP patients reported better stair-climbing ability . Enthusiasm for this finding should be tempered by the relatively small sample size 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 The purpose of the current study was to directly compare the results of fixed-bearing and mobile-bearing total knee arthroplasties in the same patient who had bilateral simultaneous total knee replacements . A fixed-bearing total knee prosthesis ( AMK ) was implanted in one knee and a mobile-bearing total knee prosthesis ( LCS ) was implanted in the other knee in 116 patients . The average age of the patients was 65 years ( range , 33–70 years ) . The average followup was 7.4 years ( range , 6–8 years ) .  Clinical and radiographic followup was done using Knee Society and Hospital for Special Surgery knee rating systems at 6 weeks , 3 months , 6 months , 1 year after surgery , and yearly thereafter . Total knee score , pain score , mean functional score , and range of motion were comparable in both groups . Two knee replacements ( 2 % ) in one patient with AMK prostheses were revised because of complete wear of tibial bearing polyethylene . One knee replacement ( 1 % ) in one patient with an LCS prosthesis was revised because of dislocation of the medial tibial bearing polyethylene and one knee replacement ( 1 % ) in one patient with an LCS prosthesis was revised because of complete wear of the medial tibial bearing polyethylene . No knee had aseptic loosening or osteolysis in either group . After a minimum followup of 6 years , the results of fixed- and mobile-bearing total knee prostheses in the current series are favorable . However , there is no evidence to prove the superiority of the mobile-bearing total knee design 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 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 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 This study compared the outcome of  total knee replacement ( TKR ) in adult patients with fixed- and mobile-bearing prostheses during the first post-operative year and at five years ' follow-up , using gait parameters as a new objective measure . This double-blind r and omised controlled clinical trial included 55 patients with mobile-bearing ( n = 26 ) and fixed-bearing ( n = 29 ) prostheses of the same design , evaluated pre-operatively and post-operatively at six weeks , three months , six months , one year and five years . Each participant undertook two walking trials of 30 m and completed the EuroQol question naire , Western Ontario and McMaster Universities osteoarthritis index , Knee Society score , and visual analogue scales for pain and stiffness . Gait analysis was performed using five miniature angular rate sensors mounted on the trunk ( sacrum ) , each thigh and calf . The study population was divided into two groups according to age ( ≤ 70 years versus > 70 years ) .  Improvements in most gait parameters at five years ' follow-up were greater for fixed-bearing TKRs in older patients ( > 70 years ) , and greater for mobile-bearing TKRs in younger patients ( ≤ 70 years ) . These findings should be confirmed by an extended age controlled study , as the ideal choice of prosthesis might depend on the age of the patient at the time of surgery After the introduction of  mobile-bearing knee arthroplasty  in the late 1970s , he benefits were discussed in comparison to the well-established modular fixed-bearing systems . The hypothetical advantages of mobile-bearing design s are the ability of axial rotation and a greater articular conformity , which reduces significantly fatigue failure of the polyethylene . Biomechanical analyses showed for each system characteristic features , which are not concordant with the aim of restoring normal knee kinematics . In both groups the long-term clinical results were excellent with 10-year survival rates of 95 - 98 % . Ligamentous stability and a perfect operative technique are key factors in mobile-bearing knee arthroplasty . Prospect i ve r and omized clinical trials are necessary to find answers concerning backside and volumetric polyethylene wear and the detrimental effects of wear particle size . Before this is accomplished , the indication for a  mobile-bearing knee arthroplasty  , especially in young patients , should be carefully considered in each case
target: Similarly , no difference was revealed between the groups for radiological outcomes or general health results .
background: 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 .