Kinematic predictors of subjective outcome after anterior cruciate ligament reconstruction: an in vivo motion analysis study In vivo kinematic comparison of posterior cruciate-retaining and posterior stabilized total knee arthroplasties under passive and weight-bearing conditions. The John Insall Award: No Functional Advantage of a Mobile Bearing Posterior Stabilized TKA Knee joint distraction compared with total knee arthroplasty: A RANDOMISED CONTROLLED TRIAL Stability and alignment do not improve by using patient-specific instrumentation in total knee arthroplasty: a randomized controlled trial Navigation of total knee arthroplasty: rotation of components and clinical results in a prospectively randomized study Changed gait pattern in patients with total knee arthroplasty but minimal influence of tibial insert design Functional comparison of posterior cruciate-retaining versus posterior stabilized total knee arthroplasty. Are undesirable contact kinematics minimized after kinematically aligned total knee arthroplasty? An intersurgeon analysis of consecutive patients Patient-specific instrumentation improved mechanical alignment, while early clinical outcome was comparable to conventional instrumentation in TKA Gait analysis and electromyography in fixed- and mobile-bearing total knee replacement: a prospective, comparative study Kinematic femoral alignment with gap balancing and patient-specific instrumentation in total knee arthroplasty: a randomized clinical trial Knee Arthroplasty With a Medially Conforming Ball-and-Socket Tibiofemoral Articulation Provides Better Function Posterior femoral translation in medial pivot total knee arthroplasty of posterior cruciate ligament retaining type. Mobile- versus fixed-bearing total knee arthroplasty: a prospective randomized controlled trial featuring 6-10-year follow-up. 4D-SPECT/CT in orthopaedics: a new method of combined quantitative volumetric 3D analysis of SPECT/CT tracer uptake and component position measurements in patients after total knee arthroplasty Risk factors predictive of joint replacement in a 2-year multicentre clinical trial in knee osteoarthritis using MRI: results from over 6 years of observation
Purpose The purpose of this study was to test whether rotational knee kinematics during dynamic pivoting activities are predictive of subjective functional outcome ( IKDC , Lysholm ) , objective laxity scores ( KT max ) , and activity levels ( Tegner ) in patients after anterior cruciate ligament reconstruction ( ACLR ) . Methods Thirty-one patients with single-bundle ACLR were evaluated prospect ively with 3D-motion analysis during ( 1 ) descending a stairway and pivoting and ( 2 ) l and ing from a jump and pivoting . The side-to-side difference of tibial rotation range of motion ( SSDTR )  between the ACLR and the contralateral intact knee was calculated for the pivoting phase of each task . Linear regression models were applied with SSDTR , for each task predictors of the subjective IKDC score , Lysholm score , anterior tibial translation , and Tegner activity level . Results SSDTR for descending and l and ing were predictive of the IKDC subjective score ( R2 = 0.46 , p < 0.001 and R2 = 0.40 , p < 0.001 , respectively ) with “ medium ” effect sizes and of the Lysholm score ( R2 = 0.13 , p < 0.05 and R2 = 0.09 , n.s . ) with “ small ” to “ none ” effect sizes . SSDTR was not predictive of anterior translation or Tegner activity level ( n.s . ) . Conclusions Restoring rotational kinematics during dynamic pivoting activities after ACLR is predictive of functional outcome . The ability of the athlete after ACLR to control tibial rotation during pivoting activities may be predictive of functional outcome .Level of evidence Case series study . Level IV An in vivo comparison of flexion kinematics for  posterior cruciate-retaining ( PCR ) and posterior stabilized ( PS ) total knee arthroplasty ( TKA ) was performed . Twenty patients who underwent bilateral paired TKAs were included in this prospect i ve study . Both PCR and PS prostheses were from the same TKA series with comparable surface geometries , and all were implanted by a single surgeon . Of these 20 patients , 3-dimensional kinematics during flexion could be analyzed using a computer model fitting technique in 18 patients . The follow-up period ranged from 18 to 53 months . In the PCR TKA , an anterior femoral translation from 30 degrees to 60 degrees of flexion was observed in the weight-bearing condition . In contrast , flexion kinematics for the PS TKA was characterized by the maintenance of a constant contact position under weight-bearing conditions and posterior femoral rollback in passive flexion 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 Aims Knee joint distraction ( KJD ) is a relatively new , knee‐joint preserving procedure with the goal of delaying total knee arthroplasty ( TKA ) in young and middle‐aged patients . We present a r and omised controlled trial comparing the two . Patients and Methods The 60 patients ≤ 65 years with end‐stage knee osteoarthritis were r and omised to either KJD ( n = 20 ) or TKA ( n = 40 ) . Outcomes were assessed at baseline , three , six , nine , and 12 months . In the KJD group , the joint space width ( JSW ) was radiologically assessed , representing a surrogate marker of cartilage thickness . Results In total 56 patients completed their allocated treatment ( TKA = 36 , KJD = 20 ) . All patient reported outcome measures improved significantly over one year ( p < 0.02 ) in both groups . At one year , the TKA group showed a greater improvement in only one of the 16 patientrelated outcome measures assessed ( p = 0.034 ) . Outcome Measures in Rheumatology‐Osteoarthritis Research Society International clinical response was 83 % after TKA and 80 % after KJD . A total of 12 patients ( 60 % ) in the KJD group sustained pin track infections . In the KJD group both mean minimum ( 0.9 mm , st and ard deviation ( SD ) 1.1 ) and mean JSW ( 1.2 mm , SD 1.1 ) increased significantly ( p = 0.004 and p = 0.0003 ) . Conclusion In relatively young patients with end‐stage knee osteoarthritis  , KJD did not demonstrate inferiority of outcomes at one year when compared with TKA . However , there is a high incidence of pin track infection associated with KJD Purpose The primary aim of the study was to examine stability and alignment after total knee arthroplasty ( TKA ) using patient-specific instrumentation ( PSI ) and conventional instrumentation ( CI ) . The hypothesis was that stability and alignment would be better using PSI than CI , 12 months postoperatively . The secondary aim included the evaluation of clinical outcomes after TKA . Methods In this prospect i ve r and omized controlled trial , 42 patients with knee osteoarthritis received a Genesis II PS prosthesis with either PSI or CI . Patients visited the hospital preoperatively and postoperatively after 6 weeks and 3 and 12 months . To evaluate stability , varus – valgus laxity was determined in extension and flexion using stress radiographs 12 months postoperatively . Three months postoperatively , a long-leg radiograph and CT scan were obtained to measure hip – knee – ankle ( HKA ) alignment and component rotation . Furthermore , frontal and sagittal alignment of the components , the Knee Society Score , VAS Pain , VAS Satisfaction , Knee injury and Osteoarthritis Outcome score , Patella score ( Kujala ) , University of California Los Angeles activity score , anterior – posterior laxity , ( serious ) adverse device-related events , and intraoperative complications were reported . The clinical outcomes were compared using independent t tests or non-parametric alternatives , and repeated measurements ANOVA with a significance level of p < 0.05 . Results No significant differences were found between the two groups regarding stability , HKA angle , and rotational alignment . In four patients , the PSI did not fit correctly on the tibia and /or femur requiring intraoperative modifications . Both groups improved significantly over time on all clinical outcomes , with no significant differences between the groups 12 months postoperatively . The PSI group showed less tibial slope than the patients in the CI group [ PSI 2.6 ° versus CI 4.8 ° ( p = 0.02 ) ] . Finally , the PSI group more frequently received a thinner insert size than the CI group ( p = 0.03 ) . Conclusions Patients operated with PSI did not differ from CI in terms of stability and alignment . However , in the PSI  group ligament releases were more often required intraoperatively . Furthermore , the two methods did not show different clinical results . It seems that the preoperative planning for the PSI facilitates more conservative bone cuts than CI , but whether this is clinical ly relevant should be investigated . Since PSI is more expensive and time consuming than CI , and does not outperform CI with regard to clinical results , we recommend to use CI.Level of evidence Background Navigation was introduced into  total knee arthroplasty ( TKA ) to improve accuracy of component position , function and survival of implants . This study was design ed to assess the outcome of navigated TKA in comparison with conventional implantation with the focus on rotational component position and clinical mid-term results . Methods In a prospect ively r and omized single-blinded approach , 90 patients with primary gonarthrosis were assigned to three different groups . Thirty patients each were assigned to NexGen LPS without and with navigation ( groups 1 and 2 ) , and 30 patients to navigation with the Stryker Scorpio PS ( group 3 ) . The navigation system used was the imageless Stryker KneeTrac , version 1.0 . Clinical outcome was assessed by a blinded observer applying the Knee Society Score ( KSS ) and a visual analogue scale ( VAS ) for pain . CT scans and radiographs were conducted prior to and 12 weeks after index surgery . Results Seventy-nine patients were available for clinical evaluation at 3 ± 0.4 years follow-up . Four implants had to be revised for early loosening or infection ( 4.4 % ) . Four patients had died and three patients were not able to follow the invitation for clinical assessment . Functional results in the KSS were significantly lower after navigated TKA . Operation time and incisions with navigation were significantly longer . Significantly less radiological outliers with navigation were found for coronal alignment of the femur , only . Conclusion In this series , no beneficial effect for navigation in TKA could be shown assessing clinical data , as functional results in the presented series seemed to be lower after first generation navigated TKA . The clinical mid- to long-term value of navigation remains to be evaluated in larger patient series or meta-analyses at longer follow-up . Trial registration numberDRKS Introduction Previous radiostereometric studies have revealed abnormal anterior-posterior translation of the femur in patients operated with AMK ( DePuy , Johnson and Johnson , Leeds , UK ) total knee arthroplasty ( TKA ) . Based on these observations , we hypothesized that patients with TKA have an abnormal gait pattern , and that there are differences in kinematics depending on the design of the tibial joint area . Method We used a gait analysis system to evaluate the influence of joint area design on the kinematics of the hip and knee during level walking .  39 TKA patients ( 42 knees ) and 18 healthy age-matched controls were studied . Patients with 5 ° varus/valgus alignment or less were r and omized to receive either a relatively flat or a concave tibial insert with retention of the posterior cruciate ligament .  Patients who had more than 5 ° varus-valgus alignment and /or extension defect of 10 ° or more were r and omized to receive the concave or a posterior-stabilized tibial component with resection of the posterior cruciate ligament . Results Patients with TKA tended to have less hip and knee extension and decreased knee and hip extension moment than controls . They also tended to walk more slowly . TKA altered the gait pattern , but choice of implant design had little influence . Interpretation In patients with a similar degree of degenerative joint disease and within the limits of the constraints offered by the prostheses under study , the choice of joint area constraint has little influence on the gait pattern A prospect i ve , r and omized comparison of posterior cruciate-retaining ( PCR ) and posterior stabilized ( PS ) total knee arthroplasties ( TKAs ) was conducted in 20 patients who underwent bilateral TKAs for osteoarthritis . All procedures were performed by a single surgeon . One knee was implanted with a PCR TKA , and a contralateral knee with a PS TKA . Both prosthetic design s were of the same TKA series , with comparable surface geometries . Patients had a clinical and radiographic evaluation at a mean of 31.7 months for PCR TKAs and 30.6 months for PS TKAs postoperatively . There were no significant differences between the PCR and PS TKAs in postoperative knee scores . However , postoperative improvement in range of motion was significantly superior in the PS group Purpose Tibiofemoral contact kinematics or knee implant motions have a direct influence on patient function and implant longevity and should be evaluated for any new alignment technique such as kinematically aligned total knee arthroplasty ( TKA ) . Edge loading of the tibial liner and external rotation ( reverse of normal ) and adduction of the tibial component on the femoral component are undesirable contact kinematics that should be minimized . Accordingly , this study determined whether the overall prevalence of undesirable contact kinematics during st and ing , mid kneeling near 90 degrees and full kneeling with kinematically aligned TKA are minimal and not different between groups of consecutive patients treated by different surgeons . Methods Three surgeons were asked to perform cemented , kinematically aligned TKA with patient-specific guides in a consecutive series of patients with their preferred cruciate-retaining ( CR ) implant .  In vivo tibiofemoral contact positions were obtained using a 3- to 2-dimensional image registration technique in 69 subjects ( Vanguard CR – TKA N = 22 , and Triathlon CR – TKA N = 47 ) . Results Anterior or posterior edge loading of the tibial liner was not observed . The overall prevalence of external rotation of the tibial component on the femoral component of 6 % was low and not different between surgeons ( n.s . ) . The overall prevalence of adduction of the tibial component on the femoral component of 4 % was low and not different between surgeons ( n.s . ) . Conclusions Kinematically aligned TKA minimized the undesirable contact kinematics of edge loading of the tibial liner , and external rotation and adduction of the tibial component on the femoral component during st and ing and kneeling , which suggests an optimistic prognosis for durable long-term function . Level of evidence III Abstract Purpose The aim of this prospect i ve study was to compare early clinical outcome , radiological limb alignment , and three-dimensional (3D)-component positioning between conventional and computed tomography (CT)-based patient-specific instrumentation ( PSI ) in primary mobile-bearing total knee arthroplasty ( TKA ) . Methods Two hundred ninety consecutive patients ( 300 knees ) with severe , debilitating osteoarthritis scheduled for TKA were included in this study using either conventional instrumentation ( CVI , n = 150 ) or PSI ( n = 150 ) . Patients were clinical ly assessed before and 2 years after surgery according to the Knee-Society-Score ( KSS ) and the visual-analog-scale for pain ( VAS ) . Additionally , the Western Ontario McMaster Universities Osteoarthritis Index ( WOMAC ) and the Oxford-Knee-Score ( OKS ) were collected at follow-up . To evaluate accuracy of CVI and PSI , hip-knee-ankle angle ( HKA ) and 3D-component positioning were assessed on postoperative radiographs and CT . Results Data of 222 knees ( CVI : n = 108 , PSI : n = 114 ) were available for analysis after a mean follow-up of 28.6 ± 5.2 months . At the early follow-up , clinical outcome ( KSS , VAS , WOMAC , OKS ) was comparable between the two groups . Mean HKA-deviation from the targeted neutral mechanical axis ( CVI : 2.2 ° ± 1.7 ° ; PSI : 1.5 ° ± 1.4 ° ; p < 0.001 ) , rates of outliers ( CVI : 22.2 % ; PSI : 9.6 % ; p = 0.016 ) , and 3D-component positioning outliers were significantly lower in the PSI group . Non-outliers ( HKA : 180 ° ± 3 ° ) showed better clinical results than outliers at the 2-year follow-up . Conclusions CT-based PSI compared with CVI improves accuracy of mechanical alignment restoration and 3D-component positioning in primary TKA . While clinical outcome was comparable between the two instrumentation groups at early follow-up , significantly inferior outcome was detected in the subgroup of HKA-outliers . Level of evidence Prospect i ve comparative study , Level II 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 While patient-specific instrumentation ( PSI ) in total knee arthroplasty ( TKA ) allows for transfer of the preoperative plan onto bony l and marks , the soft tissue balancing is not affected . The goals of this r and omized clinical trial were to compare PSI and the measured resection technique ( conventional ) with PSI and the gap balancing technique .  Fifty patients were r and omized to TKA with conventional PSI ( PSI-S ) ( n = 25 ) or to PSI with additional gap balancing ( PSI-GB ) ( n = 25 ) . All patients were clinical ly examined at 3 and 12 months postoperatively . Data on the range of motion , the Knee Society Score , the Western Ontario and McMasters Universities Osteoarthritis Index , the High-Flexion Knee Score ( HFKS ) , and the Forgotten Joint Score ( FJS ) were compiled at follow-up . Statistically significant improvements were found for all clinical parameters in the PSI-GB group compared to the PSI-S group at 3 months postoperatively and for FS , FJS , and HFKS at 12 months . However , the relevance of these differences , as well as their effect on long-term outcomes , needs to be evaluated further . In conclusion , patient-specific instrumentation combined with gap balancing yielded good early clinical outcomes Background A knee design with a ball- and -socket articulation of the medial compartment has a femoral rollback profile similar to the native knee . Compared to a conventional , posterior-stabilized knee design , it provides AP stability throughout the entire ROM . However , it is unclear whether this design difference translates to clinical and functional improvement . Questions / purpose sWe asked whether the medially conforming ball- and -socket design differences would be associated with ( 1 ) improved ROM ; and ( 2 ) improved American Knee Society , WOMAC , Oxford Knee , SF-36 , and Total Knee Function Question naire scores compared to a conventional , fixed-bearing posterior-stabilized TKA . Patients and Methods We enrolled 82 patients in a single-center , single-blinded , r and omized , controlled trial comparing the medially conforming ball- and -socket design knee prosthesis to a posterior-stabilized total knee prosthesis .  Our primary end point was ROM . Our secondary end points were American Knee Society , WOMAC , Oxford Knee , SF-36 , and Total Knee Function Question naire scores . All patients were followed at 1 and 2 years . Results The mean ROM was 100.1 ° and 114.9 ° in the posterior-stabilized and medially conforming ball- and -socket groups , respectively . The physical component scores of SF-36 and Total Knee Function Question naire were better in the medially conforming ball- and -socket group . We found no difference in American Knee Society , WOMAC , and Oxford Knee scores . Conclusions Both implant design s similarly relieved pain and improved function . The medially conforming ball- and -socket articulation provided better high-end function as reflected by the Total Knee Function Question naire . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence PURPOSE To report clinical results and demonstrate posterior femoral translation ( PFT ) in medial pivot total knee arthroplasty ( TKA ) of posterior cruciate ligament ( PCL ) retaining type . MATERIAL S AND METHODS A prospect i ve study was performed upon thirty consecutive subjects who were operated on with medial pivot TKA of PCL retaining type between March 2009 and March 2010 and had been followed up for at least 2 years . Clinical ly , the knee society knee score and function score were used . In full extension and active flexion lateral radiograph , anteroposterior ( AP ) condylar position and magnitude of PFT was determined . RESULTS At last follow-up , the mean knee society knee score and function score improved significantly compared to preoperative scores . The AP condylar positions were consistently posterior to midline throughout the entire range of flexion . The PFTs averaged 0.31 ( ±0.12 ) of half length of tibial base plate and were greater in higher flexion cases ( r = 0.56 , p = 0.0012 ) . There were no cases having either component migration or radiolucent line wider than 2 mm except for one case showing instability related to trauma . CONCLUSIONS In medial pivot TKA of PCL retaining type , clinical outcomes were satisfactory and posterior femoral translations were consistently observed during progressive flexions of knees at two- to three-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 Objective The purpose was to evaluate the intra- and inter-observer reliability of combined quantitative 3D-volumetric single-photon emission computed tomography (SPECT)/CT analysis including size , intensity and localisation of tracer uptake regions and total knee arthroplasty ( TKA ) position . Material s and methods Tc-99m-HDP-SPECT/CT of 100 knees after TKA were prospect ively analysed . The anatomical areas represented by a previously vali date d localisation scheme were 3D-volumetrically analysed . The maximum intensity was recorded for each anatomical area . Ratios between the respective value and the mid-shaft of the femur as the reference were calculated . Femoral and tibial TKA position ( varus – valgus , flexion – extension , internal rotation– external rotation ) were determined on 3D-CT . Two consultant radiologists/nuclear medicine physicians interpreted the SPECT/CTs twice with a 2-week interval . The inter- and intra-observer reliability was determined ( ICCs ) . Kappa values were calculated for the area with the highest tracer uptake between the observers . Results The measurements of tracer uptake intensity showed excellent inter- and intra-observer reliabilities for all regions ( tibia , femur and patella ) . Only the tibial shaft area showed ICCs < 0.89 . The kappa values were almost perfect ( 0.856 , p < 0.001 ; 95 % CI 0.778 , 0.922 ) . For measurements of the TKA position , there was strong agreement within and between the readings of the two observers ; the ICCs for the orientation of TKA components for inter- and intra-observer reliability were nearly perfect ( ICCs > 0.84 ) . Conclusion This combined 3D-volumetric st and ardised method of analysing the location , size and the intensity of SPECT/CT tracer uptake regions ( “ hotspots ” ) and the determination of the TKA position was highly reliable and represents a novel promising approach to biomechanics Objective To identify predictive factors for total knee replacement ( TKR ) using data from MRI of knee osteoarthritis patients in a phase III multicentre disease-modifying osteoarthritis drug ( DMOAD ) study . Methods Knee osteoarthritis patients from a 2-year clinical trial evaluating licofelone versus naproxen  were investigated for the incidence of TKR of the study knee . Patients ( n=161 ) who completed the study according to protocol were selected . Incidence of TKR was assessed blindly to the treatment following telephone interviews ( n=123 ) . Results 18 TKR ( 14.6 % ) were performed in 4–7 years following enrolment in the original study . More TKR were performed within the naproxen than the licofelone group ( 61 % vs 39 % , p=0.232 ) . Baseline score of bone marrow lesions ( BML ) in the medial compartment ( p=0.0001 ) , medial joint space width ( JSW ) as assessed by st and ardised radiographs ( p=0.0008 ) , presence of severe medial meniscal tear ( p=0.004 ) , medial meniscal extrusion ( p=0.013 ) , and C-reactive protein level ( p=0.049 ) were strong predictors of TKR . Changes at the end of the study also yielded strong predictors : change in cartilage volume of the medial compartment ( p=0.005 ) and of the global knee ( p=0.034 ) , reduction in the JSW of greater than 7 % ( p=0.009 ) , and WOMAC pain ( p=0.009 ) and function ( p=0.023 ) scores . Multivariate analysis showed that baseline severe medial meniscal tear ( p=0.023 ) and presence of medial BML ( p=0.025 ) were the strongest independent long-term predictors of TKR . Conclusion This study shows that in the context of osteoarthritis trials , clinical data and structural changes identified by MRI allow prediction of a ‘ hard ’ outcome such as TKR . The findings support the usefulness and predictive value of MRI in defining study outcome in DMOAD trials
Conclusion Based on the small number of studies with appropriate statistical analysis , we are unable to reach a clear conclusion in the clinical performance of medial stabilized knee replacement construct .
Background Medial stabilized  total knee joint replacement ( TKJR ) construct is design ed to closely replicate the kinematics of the knee .
Little is known regarding comparison of clinical functional outcomes of patients utilising vali date d patient reported outcome measures ( PROM ) after medial stabilized TKJR and other construct design s. Purpose To perform a systematic review of the available literature related to the assessment of clinical functional outcomes following a  TKJR  employing a medial stabilized construct design .