title: Posterior-stabilized versus cruciate-retaining total knee arthroplasty: balancing the gap. Randomised, prospective study comparing cemented and cementless total knee replacement: results of press-fit condylar total knee replacement at five years. Cemented tibial component fixation performs better than cementless fixation A randomised controlled trial of cemented versus cementless press-fit condylar total knee replacement: 15-year survival analysis. Functional outcome of PFC Sigma fixed and rotating-platform total knee arthroplasty. A prospective randomised controlled trial [Comparative study of fixation mode in total knee arthroplasty with preservation of the posterior cruciate ligament]. A randomised, controlled trial of cemented versus cementless press-fit condylar total knee replacement. Ten-year survival analysis. Uncemented HA-coated Implant is the Optimum Fixation for TKA in the Young Patient Patient-reported outcomes after fixed- versus mobile-bearing total knee replacement: a multi-centre randomised controlled trial using the Kinemax total knee replacement. The Effect of Hydroxyapatite on the Micromotion of Total Knee Prostheses. A Prospective, Randomized, Double-Blind Study* Hydroxyapatite coating versus cemented fixation of the tibial component in total knee arthroplasty: prospective randomized comparison of hydroxyapatite-coated and cemented tibial components with 5-year follow-up using radiostereometry. Comparison of mobile-bearing and fixed-bearing total knee arthroplasty: a prospective randomized study. The Knee Arthroplasty Trial (KAT) design features, baseline characteristics, and two-year functional outcomes after alternative approaches to knee replacement. The Lower Extremity Functional Scale (LEFS): scale development, measurement properties, and clinical application. North American Orthopaedic Rehabilitation Research Network. Should we reconsider all-polyethylene tibial implants in total knee replacement? Mobile vs. fixed meniscal bearing in total knee replacement: a randomised radiostereometric study. Fixed- versus Mobile-Bearing Total Knee Arthroplasty in Indian Patients Rotating Platform Knees Did Not Improve Patellar Tracking: A Prospective, Randomized Study of 240 Primary Total Knee Arthroplasties Scintimetry after total knee arthroplasty. Prospective 2-year study of 18 cases of arthrosis and 15 cases of rheumatoid arthritis. A randomized controlled trial comparing "high-flex" vs "standard" posterior cruciate substituting polyethylene tibial inserts in total knee arthroplasty. Early Inducible Displacement of Tibial Components in Total Knee Prostheses Inserted with and without Cement. A Randomized Study with Roentgen Stereophotogrammetric Analysis* Hydroxyapatite-coated tibial implants compared with cemented tibial fixation in primary total knee arthroplasty. A randomized trial of outcomes at five years. Deep-Dish Congruent Tibial Component Use in Total Knee Arthroplasty: A Randomized Prospective Study Concave versus posterior-stabilized tibial joint surface in total knee arthroplasty: randomized evaluation of 47 knees. [Prospective randomized comparative study of early functional outcome of 2 knee joint endoprosthesis systems--rotation plateau versus fixed polyethylene inlay]. Increased varus-valgus tilting of screw-fixated knee prostheses. Stereoradiographic study of uncemented versus cemented tibial components. Kinematics of Three Variations of the Freeman-Samuelson Total Knee Prosthesis Midterm comparison of posterior cruciate-retaining versus -substituting total knee arthroplasty using the Genesis II prosthesis. A multicenter prospective randomized clinical trial.
abstract: A prospect i ve , r and omized , double-blind trial was carried out to compare  cruciate-retaining ( CR ) and posterior-stabilized ( PS ) total knee arthroplasties ( TKAs ) . A total of 40 knees were r and omized to receive either a NexGen CR ( Zimmer , Warsaw , IN ) or a Legacy PS ( Zimmer , Warsaw , IN ) TKA . All knees were implanted with identical surgical technique , making sure to balance precisely the flexion-extension gaps before implantation of the components . At 2-year follow-up , there was no difference between the CR and the PS TKAs with respect to their Knee Society clinical , functional , and radiographic scores . These findings suggest that with careful attention to surgical technique and balancing the knee , orthopaedic surgeons should expect similar results whether they use a CR or PS TKA Early implants for total knee replacement  were fixed to bone with cement . No firm scientific reason has been given for the introduction of cementless knee replacement and the long-term survivorship of such implants has not shown any advantage over cemented forms . In a r and omised , prospect i ve study we have compared  cemented and uncemented total knee replacement  and report the results of 139 prostheses at five years . Outcome was assessed both clinical ly by independent examination using the Nottingham knee score and radiologically using the Knee Society scoring system . Independent statistical analysis of the data showed no significant difference between cemented and cementless fixation for pain , mobility or movement . There was no difference in the radiological alignment at five years , but there was a notable disparity in the radiolucent line score . With cemented fixation there was a significantly greater number of radiolucent lines on anteroposterior radiographs of the tibia and lateral radiographs of the femur . At five years , our clinical results would not support the use of the more expensive cementless fixation whereas the radiological results are of unknown significance . Longer follow-up will determine any changes in the results and conclusions Background The question whether the tibial component of a total knee arthroplasty  should be fixed to bone with or without bone cement has not yet been definitely answered . We studied movements between the tibial component and bone by radiostereometry ( RSA ) in total knee replacement ( TKR ) for 3 different types of fixation : cemented fixation ( C-F ) , uncemented porous fixation ( UC-F ) and uncemented porous hydroxyapatite fixation ( UCHA-F ) . Patients 116 patients with osteoarthrosis , who had 146 TKRs , were included in 2 r and omized series . The first series included 86 unilateral TKRs stratified into 1 of the 3 types of fixation . The second series included 30 patients who had simultaneous bilateral TKR surgery , and who were stratified into 3 subgroups of pairwise comparisons of the 3 types of fixation . Results After 5 years 2 knees had been revised , neither of which were due to loosening . 1 UCHA-F knee in the unilateral series showed a large and continuous migration and a poor clinical result , and is a pending failure . The C-F knees rotated and migrated less than UC-F and UCHA-F knees over 5 years . UCHA-F  migrated less than UC-F after 1 year . Interpretation Cementing of the tibial component offers more stable bone-implant contact for 5 years compared to uncemented fixation . When using uncemented components , however , there is evidence that augmenting a porous surface with hydroxyapatite may mean less motion between implant and bone after the initial postoperative year We report the long-term survival of a prospect i ve r and omised consecutive series of 501 primary knee replacements using the press-fit condylar posterior cruciate ligament-retaining prosthesis .  Patients received either cemented ( 219 patients , 277 implants ) or cementless ( 177 patients , 224 implants ) fixation . Altogether , 44 of 501 knees ( 8.8 % ) underwent revision surgery ( 24 cemented vs 20 cementless ) . For cemented knees the 15-year survival rate was 80.7 % ( 95 % confidence interval ( CI ) 71.5 to 87.4 ) and for cementless knees it was 75.3 % ( 95 % CI 63.5 to 84.3 ) . There was no significant difference between the two groups ( cemented vs cementless ; hazard ratio ( HR ) 0.83 , 95 % CI 0.45 to 1.52 , p = 0.55 ) . When comparing the covariates there was no significant difference in the rates of survival between the side of operation ( HR 0.58 , p = 0.07 ) , age ( HR 0.97 , p = 0.10 ) and diagnosis ( HR 1.25 p = 0.72 ) . However , there was a significant gender difference , with males having a higher failure rate with cemented fixation ( HR 2.48 , p = 0.004 ) . Females had a similar failure rate in both groups . This single-surgeon series , with no loss to follow-up , provides reliable data of the revision rates of one of the most commonly-used total knee replacements . The survival of the press-fit condylar total knee replacement remained good at 15 years , irrespective of the method of fixation 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 OF THE STUDY We performed a prospect i ve r and omized study to compare two fixation modes , with and without cement , for total knee arthroplasty . MATERIAL AND METHODS The study series was composed of 96 cemented or noncemented total knee arthroplasties performed between May 1993 and October 1995 . The only difference was the diamond interface used for cemented prostheses and the mesh interface used for uncemented prostheses . The operator was unaware of the type of fixation until the bone slices had been obtained . We assessed outcome in 73 cases with a mean follow-up of 27 months . The two population s were comparable for preoperative clinical status , bone tophicity and surgical procedure . RESULTS The mean duration of the operation was sgnificantly longer ( > 10 min ) for the cemented protheses . The complication rates were comparable but we did have two mobilizations of the tibial implant in the noncemented group . The total scores ( 127 + /- 29 in the cemented group versus 135 + /- 20 in the uncemented group ) were significantly different . There were however more cases with degradation of the controlateral knee in the cemented group although the difference was not significant . When these cases were excluded from the analysis , the total scores for two groups were similar ( 143 and 140 respectively ) . Radiographic outcome was quite different with mobilization of the tibial implant in 2 cases and the rate of lucent borders was significantly higher in the noncemented group . DISCUSSION AND CONCLUSION While the clinical outcome was comparable , the quality of the fixation was significantly better with cemented arthroplasty , which remains the gold st and ard We have carried out a long-term survival analysis of a prospect i ve , r and omised trial comparing cemented with cementless fixation of press-fit condylar primary total knee replacements . A consecutive series of 501 replacements received either cemented ( 219 patients , 277 implants ) or cementless ( 177 patients , 224 implants ) fixation .  The patients were contacted at a mean follow-up of 7.4 years ( 2.7 to 13.0 ) to establish the rate of survival of the implant . The ten-year survival was compared using life-table and Cox 's proportional hazard analysis . No patient was lost to follow-up . The survival at ten years was 95.3 % ( 95 % CI 90.3 to 97.8 ) and 95.6 % ( 95 % CI 89.5 to 98.2 ) in the cemented and cementless groups , respectively . The hazard ratio for failure in cemented compared with cementless prostheses was 0.97 ( 95 % CI 0.36 to 2.6 ) . A comparison of the clinical outcome at ten years in 80 knees showed no difference between the two groups . The survival of the press-fit condylar total knee replacement at ten years is good irrespective of the method of fixation and brings into question the use of more expensive cementless implants Fixation of the tibial component in total knee arthroplasty in younger patients remains controversial . We evaluate the results of three different types of fixation of the Profix total knee arthroplasty  in a r and omized controlled trial of 97 consecutive knees ( 85 patients ) with osteoarthrosis or inflammatory arthritis with 2-year followup of all patients . We r and omized patients to three different types of fixation of the tibial component : cemented , uncemented ( HA coated ) with screws , or uncemented ( HA coated ) without screws . We performed clinical evaluations and radiostereometric analysis at 6 weeks , and 3 , 6 , 12 and 24 months postoperatively . The knees in the uncemented groups migrated more than those in the cemented group during the first 3 months , but at 2 years we observed no differences . The uncemented implants  displayed all migration within the first 3 months . The cemented implants did not stabilize but had continuously increasing migration during the followup . Cementless implants without screws  did not migrate more than implants with screws and displayed similar pattern of migration , indicating screws do not improve fixation .  Uncemented fixation using hydroxyapatite-coated implants without screws seems to be the best solution for the younger patient . Level of Evidence : Therapeutic Level I. See the Guidelines for Authors for a complete description of levels of evidence We compared patient-reported outcomes of the Kinemax fixed- and mobile-bearing total knee replacement in a multi-centre r and omised controlled trial . Patients were  r and omised to the fixed- or the mobile-bearing prosthesis via a sealed envelope method after the bone cuts had been made in the operating theatre . R and omisation was stratified by centre and diagnosis . Patients were assessed pre-operatively and at eight to 12 weeks , one year and two years post-operatively . Vali date d question naires were used which included the Western Ontario MacMasters University , Short-Form 12 , Mental Health Index-5 , Knee Injury and Osteoarthritis Outcome Score for Knee-Related Quality of Life and Function in Sport and Recreation scales and a vali date d scale of satisfaction post-operatively . In total , 242 patients ( 250 knees ) with a mean age of 68 years ( 40 to 80 ) were recruited from four NHS orthopaedic centres . Of these , 132 patients ( 54.5 % ) were women . No statistically significant differences could be identified in any of the patient-reported outcome scores between patients who received the fixed-bearing or the mobile-bearing knee up to two-years post-operatively A prospect i ve , r and omized , double-blind study was performed to evaluate three different means of fixing tibial components  during total knee arthroplasty . Eleven components fixed with cement , ten hydroxyapatite-coated components fixed without cement  , and ten noncoated components fixed without cement were studied . A posterior cruciate ligament-retaining total condylar implant was used . Micromotion of the components was assessed with roentgen stereophotogrammetric analysis during the two-year follow-up period . There were no significant differences among the patients with regard to age ( mean [ and st and ard deviation ] , 68 ± 11.6 years ) , body-mass index ( mean , 23 ± 2.8 kilograms per square meter ) , or stage of osteoarthrosis ( mean , 4 ± 2.4 according to the classification system of Ahlbäck and 5 ± 0.6 according to that of Larsen et al. ) . The diagnosis was osteoarthrosis in five knees , and it was rheumatoid arthritis in twenty-six .  The clinical scores were similar among the study groups . According to the system of the Knee Society , the mean preoperative functional score was 10 ± 2.9 points and the mean preoperative knee score was 24 ± 3.2 points . At the two-year follow-up evaluation , these scores were 41 ± 8.3 and 79 ± 3.2 points , respectively . A significant difference with regard to micromotion was found between the noncoated components fixed without cement and the hydroxyapatite-coated components fixed without cement as well as between the noncoated components fixed without cement and the components fixed with cement ( p < 0.001 , analysis of variance ) . The hydroxyapatite-coated components fixed without cement and the components fixed with cement both had far less micromotion along the longitudinal axis ( subsidence ) throughout the follow-up period than did the noncoated components fixed without cement . At the two-year follow-up evaluation , the subsidence of the noncoated components was -0.73 ± 0.924 millimeter , the subsidence of the cemented components was -0.05 ± 0.109 millimeter , and the subsidence of the hydroxyapatite-coated components was -0.06 ± 0.169 millimeter . The cemented components as well as the hydroxyapatite-coated components also had less translation along the transverse axis ( p < 0.001 , analysis of variance ) and the sagittal axis ( p < 0.001 , analysis of variance ) compared with the noncoated components . In conclusion , micromotion of hydroxyapatite-coated tibial components fixed without cement was similar to that of tibial components fixed with cement . Therefore , hydroxyapatite , a biological mediator , may be necessary for the adequate fixation of tibial components when cement is not used Fifty-three consecutive patients ( 57 knees ; mean age , 69 years ) entered a prospect i ve r and omized study to compare the fixation of hydroxyapatite (HA)-coated ( 29 knees ) with cemented ( 28 knees ) tibial components in the Tricon II total knee arthroplasty . The quality of the fixation during 5 years postoperatively was evaluated with radiostereometric analysis ( RSA ) . Three HA-coated implants were revised : 2 owing to infection , and 1 owing to early delamination of the coating and clinical loosening . Eight patients ( 9 knees ) died , 1 patient sustained a stroke  , and 1 patient refused investigations after 1 year . In the 40 patients ( 19 HA-coated , 21 cemented ) remaining at 5 years , the magnitude of the micromotion between the HA-coated and cemented groups did not differ . The HA-coated implants displayed most of the migration within the initial 3 months then stabilized , whereas the cemented implants showed an initially lower , but over time continuously increasing migration . Between 1 and 2 years , 4 of 24 HA-coated and 10 of 23 cemented implants  migrated > 0.2 mm and were categorized unstable , which has been shown to have a prognostic value as regards future aseptic loosening . Progressive radiolucent lines developed in 2 cemented knees , which both were categorized unstable . If HA-coated implants can sustain the forces that threaten the fixation in the early period after implantation , a strong and enduring fixation may be obtained 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 BACKGROUND The aim of continued development of total knee replacement systems has been the further improvement of the quality of life and increasing the duration of prosthetic survival . Our goal was to evaluate the effects of several design features , including metal backing of the tibial component , patellar resurfacing , and a mobile bearing between the tibial and femoral components , on the function and survival of the implant . METHODS A pragmatic , multicenter , r and omized , controlled trial involving 116 surgeons in thirty-four centers in the United Kingdom was performed ; 2352 participants were r and omly allocated to be treated  with or without a metal backing of the tibial component ( 409 ) , with or without patellar resurfacing ( 1715 ) , and /or with or without a mobile bearing ( 539 ) . R and omization to more than one comparison was allowed . The primary outcome measures were the Oxford Knee Score ( OKS ) , Short Form-12 , EuroQol-5D , and the need for additional surgery . The results up to two years postoperatively are reported . RESULTS Functional status and quality -of-life scores were low at baseline but improved markedly across all trial groups following knee replacement ( mean overall OKS , 17.98 points at baseline and 34.82 points at two years ) . Most of the change was observed at three months after the surgery . Six percent of the patients had additional knee surgery within two years . There was no evidence of differences in clinical , functional , or quality -of-life measures between the r and omized groups at two years . CONCLUSIONS Patients have substantial improvement following total knee replacement . This is the first adequately powered r and omized controlled trial , of which we are aware , in which the effects of metal backing , patellar resurfacing , and a mobile bearing were investigated . We found no evidence of an effect of these variants on the rate of early complications or on functional recovery up to two years after total knee replacement BACKGROUND AND PURPOSE The purpose of this study was to assess the reliability , construct validity , and sensitivity to change of the Lower Extremity Functional Scale ( LEFS ) . SUBJECTS AND METHODS The LEFS was administered to 107 patients with lower-extremity musculoskeletal dysfunction referred to 12 outpatient physical therapy clinics . METHODS The LEFS was administered during the initial assessment , 24 to 48 hours following the initial assessment , and then at weekly intervals for 4 weeks . The SF-36 ( acute version ) was administered during the initial assessment and at weekly intervals . A type 2,1 intraclass correlation coefficient was used to estimate test-retest reliability . Pearson correlations and one-way analyses of variance were used to examine construct validity . Spearman rank-order correlation coefficients were used to examine the relationship between an independent prognostic rating of change for each patient and change in the LEFS and SF-36 scores . RESULTS Test-retest reliability of the LEFS scores was excellent ( R = .94 [ 95 % lower limit confidence interval ( CI ) = .89 ] ) . Correlations between the LEFS and the SF-36 physical function subscale and physical component score were r=.80 ( 95 % lower limit CI = .73 ) and r = .64 ( 95 % lower limit CI = .54 ) , respectively . There was a higher correlation between the prognostic rating of change and the LEFS than between the prognostic rating of change and the SF-36 physical function score . The potential error associated with a score on the LEFS at a given point in time is + /-5.3 scale points ( 90 % CI ) , the minimal detectable change is 9 scale points ( 90 % CI ) , and the minimal clinical ly important difference is 9 scale points ( 90 % CI ) . CONCLUSION AND DISCUSSION The LEFS is reliable , and construct validity was supported by comparison with the SF-36 . The sensitivity to change of the LEFS was superior to that of the SF-36 in this population . The LEFS is efficient to administer and score and is applicable for research purpose s and clinical decision making for individual patients The role of modular tibial implants in total knee replacement is not fully defined . We performed a prospect i ve r and omised controlled clinical trial using radiostereophotogrammetric analysis to compare the performance of an all-polyethylene tibia with a metal-backed cruciate-retaining condylar design , PFC-Sigma total knee replacement for up to 24 months . There were 51 patients who were r and omised into two treatment groups . There were 10 subsequent withdrawals , leaving 21 all-polyethylene and 20 metal-backed tibial implants . No patient was lost to follow-up . There were no significant demographic differences between the groups . At two years one metal-backed implant showed migration > 1 mm , but no polyethylene implant reached this level . There was a significant increase in the SF-12 and Oxford knee scores after operation in both groups . In an uncomplicated primary total knee replacement the all-polyethylene PFC-Sigma tibial prosthesis showed no statistical difference in migration from that of the metal-backed counterpart . There was no difference in the clinical results as assessed by the SF-12 , the Oxford knee score , alignment or range of movement at 24 months , although these assessment measures were not statistically powered in this study 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 . 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 Renewed interest in mobile-bearing total knee replacement design s has been generated by the concept of self alignment and the suggestion that those design s can accommo date small mismatches in the rotational position of the tibial and femoral components . Self alignment might improve patellar tracking , decrease the prevalence of lateral retinacular release and postoperative patellar tilt or subluxation , improve knee flexion , and improve patellofemoral function during daily activities such as stair climbing . This prospect i ve r and omized study of 240 patients used a single posterior-stabilized femoral component  and included three groups of 80 patients : an  all-polyethylene group , a modular metal-backed group , and a rotating platform tibia group . The prevalence of lateral retinacular release was 3.8 % in each group . The prevalence of patellar tilt was 5 % ( all-polyethylene group ) , 7 % ( modular metal-backed group ) , and 11 % ( rotating platform group ) . Preoperative motion was not significantly different and both the 3-month flexion ( 112 ° , 110 ° , and 108 ° ) and 1-year flexion ( 116 ° , 117 ° , and 115 ° ) were not significantly different among the all-polyethylene , modular metal-backed , and rotating platform groups , respectively . Preoperative stair climbing scores were not significantly different and both the 3-month ( 38 , 41 , and 35 points ) and 1-year ( 44 , 46 , and 42 points ) scores were not significantly different . In this prospect i ve r and omized study , the rotating platform knee design did not decrease the prevalence of lateral retinacular release or patellar tilt or subluxation and did not increase knee flexion or improve stair climbing ability at 3 months or at 1 year postoperatively when compared with a posterior-stabilized , fixed-bearing knee 33 consecutive patients ( 18 arthrosis , 15 rheumatoid arthritis ) , operated on with total knee arthroplasty and r and omized to cemented ( 18 knees ) or cementless fixation ( 15 knees ) , were investigated with scintimetry 3 , 6 , 12 , and 24 months postoperatively .  Migration was evaluated with simultaneous  roentgen stereophotogrammetric ( RSA ) examinations .  The scintimetric activity in the ipsilateral femoral diaphysis decreased and the activity in the tibial diaphysis increased during the observation period . Constant and low activity was recorded in front of the femoral component . This region was chosen as a reference . Three months after surgery , high activity was noted under the tibial component in knees with a preoperative varus deformity . After 2 years , the activity had decreased to the same level as in the patients with a valgus deformity . Diagnosis and mode of fixation did not influence the activity . Low postoperative activity was recorded in the tibial metaphyses if no rotatory displacement of the tibial component occurred The purpose of this study is to compare the range of motion and clinical outcomes of a st and ard posterior-stabilized ( PS ) vs the high-flex ( HF ) polyethylene tibial insert of a posterior cruciate substituting total knee arthroplasty system . One hundred patients were entered into a prospect i ve , blinded , r and omized clinical trial in which 50 patients received a Genesis II PS insert and 50 patients received a Genesis II HF insert ( Smith & Nephew , Memphis , TN ) . At an average follow-up of 2.7 years ( range , 2.3 - 3.1 years ) , there were no differences in any outcome measures ( Western Ontario and McMaster Universities osteoarthritis index , Short-Form 12 , Knee Society clinical rating scores , anterior knee pain ) . There were no differences ( P = .811 ) in average knee flexion at 2 years ( st and ard , 123 degrees + /- 7 degrees ; HF , 124 degrees + /- 7 degrees ) . In summary , this prospect i ve blinded r and omized clinical trial demonstrated no differences between a PS and HF polyethylene design . Long-term evaluation will be required to comment on differences in polyethylene wear and implant longevity The  fixation of tibial components r and omized to insertion with or without cement in  twenty-six knees was examined for inducible displacement at six weeks and one year postoperatively with use of roentgen stereophotogrammetric analysis . Furthermore , migration was studied during the first two postoperative years . Inducible displacement was found in all knees at both the six-week and the one-year follow-up examination , but no differences were detected with respect to the type of fixation ( p > 0.05 ) . All tibial components  migrated for as long as one year postoperatively , after which most stabilized . No difference was found between the groups with respect to migration during the first two years postoperatively ( p > 0.05 ) , with the exception of subsidence of the component , which was found to be 0.0 ± 0.1 millimeter ( mean and st and ard error of the mean ) for the components inserted with cement and 0.5 ± 0.1 millimeter for the components inserted without cement ( p < 0.01 ) . Migration after one year was the same for both groups . We found a relationship between inducible displacement at six weeks and at one year as well as one between inducible displacement and migration at one year . To our knowledge , the present study is the first in which the micromotion of an interference-fit prosthesis was found to be similar to that of a device inserted with cement . The results of the present study emphasize the importance of the initial prosthetic fixation BACKGROUND Although excellent long-term results have been reported with cemented tibial fixation , cementless fixation as a means to improve the longevity of total knee prostheses continues to be of interest to clinicians . The purpose of this study was to compare outcomes between cementless tibial fixation with hydroxyapatite and cemented tibial fixation in the first five years following primary total knee arthroplasty . METHODS We performed a prospect i ve , r and omized clinical trial that included eighty-one patients with noninflammatory knee arthritis who underwent primary total knee arthroplasty when they were less than seventy years of age . The subjects were r and omized at the time of surgery to be treated with either cementless tibial fixation with hydroxyapatite or cemented tibial fixation . Evaluations were performed preoperatively and at six months , one year , and five years postoperatively by a physical therapist who was blinded to group allocation . Self-reported pain and function , the primary outcomes , were measured with the Western Ontario and McMaster Universities Osteoarthritis Index ( WOMAC ) and the R AND 36-Item Health Survey ( R AND -36 ) . Complications and revision rates were determined through a review of hospital records and at each patient evaluation . The Knee Society radiographic score was used to evaluate plain radiographs at each assessment . RESULTS Seventy subjects ( 86 % ) completed the five-year assessment . Slightly more pain was reported in the hydroxyapatite group at six months as measured with both the WOMAC and the R AND -36 , a difference that disappeared by one year postoperatively . No differences were seen in function , radiographic findings , or complications . No subject required revision of the tibial prosthesis during the study . CONCLUSIONS At five years postoperatively , there is no difference between cementless tibial fixation with hydroxyapatite and cemented tibial fixation in terms of self-reported pain , function , health-related quality of life , postoperative complications , or radiographic scores One hundred seventy-six patients with osteoarthritis of the knee were r and omized prospect ively into two groups . In both groups the posterior cruciate ligament was released from its femoral attachment . In one group a posterior stabilized tibial component was used whereas in the other group a deep-dish tibial polyethylene component was inserted ( Genesis II ) . The surgical and perioperative technique was identical in both groups and all the implants were cemented to their respective bones . Patients began range of motion exercises within the first few hours after surgery and were allowed weightbearing to tolerance beginning on the first postoperative day . At followup there was no statistical difference in the mean range of flexion ( approximately 116 ° ) , ability to ascend and descend stairs in a bipedal manner ( 80 % ) , pain scores , knee scores ( 94 points ) , stability , or the lack of anterior knee pain . Postoperative implant alignment in the sagittal and coronal planes and on Merchant skyline views was excellent in both groups . There was only one lateral release required and that was in one patient who received a deep-dish component . Using deep-dish implant obviates the need to resect intercondylar femoral bone , decreasing the potential for fracture and maximizing bone volume should revision be necessary in the future Forty-seven knees in 43 patients with severe deformities r and omly received AMK total knee arthroplasty with concave ( C , n = 25 ) or posterior-stabilized ( PS , n = 22 ) polyethylene insert and with resection of the posterior cruciate ligament . Radiostereometric examinations were done postoperatively and after 3 , 12 , and 24 months . Two patients ( 1 C , 1 PS ) underwent revision surgery . At the 2-year follow-up , the median absolute rotations of the tibial inserts ranged from 0.13 degrees to 0.26 degrees ( C vs PS ; P = .1-.7 ) . The maximum total point motion was almost identical in the 2 groups ( C , 0.38 ; PS , 0.39 ; P = .9 ) . Maximum subsidence , lift-off , and Hospital for Special Surgery scores did not differ ( P = .1-.6 ) . Recipients of 20 of 24 knees with concave design and 14 of 19 knees with posterior-stabilized design reported that their knee could be regarded as normal or almost normal . Variations of the configuration of the polyethylene insert did not alter the outcome in the short term AIM Different systems are used for total knee arthroplasty ( TKA ) . Compared were a press-fit femur condyle replacement system with fixed tibial PE-inlay versus a rotating tibia component system with an emphasis on the early functional results . METHOD Patient selection and the use of the  Knee Society Score for this r and omized and prospect i ve study were based on the directives for TKA of the german Society for Orthopaedic and Trauma Surgery ( DGOT ) . We examined the patients post-operatively after 1 week , 2 weeks , 6 weeks , 3 months , 6 months , and 1 year . RESULTS After 6 weeks an increase of the total knee score could be seen in both groups . The total knee score of the rotating tibia component  increased from 93.96 pre-operatively to 113.57 after 6 weeks , to 139.82 after 3 months , to 154.32 after 6 months , and to 159.65 after one year . The total score with the fixed PE-inlay increased from 79.75 to 111.5 after 6 weeks , to 128.25 after 3 months , to 134.08 after 6 months , and to 130.08 after one year . CONCLUSION After 6 weeks the implant with the rotating tibia component showed a lasting higher score as compared to the implant with a fixed PE-inlay component using the same early rehabilitation and mobilization techniques Twenty-six women and three men ( 34 knees ) with osteoarthrosis were operated with the Miller-Galante I ( Zimmer , Warsaw , IN ) knee prosthesis . The patients were r and omized to either cemented or uncemented fixation of the tibial component . All patients received a TiVaAl alloy tibial plate with four pegs and titanium fiber-mesh undersurface . In the uncemented knees four screws were added . The fixation of the tibial component was determined by roentgen stereophotogrammetric analysis during the first 2 postoperative years . Rotations of the entire tibial component were recorded , as well as proximal or distal translation of various parts of the prosthetic edge corresponding to subsidence and lift-off . The uncemented components displayed almost all rotation and translation during the first 6 weeks , whereas the cemented ones displayed a more gradually increasing migration during the 2 years . Tibial component rotation about the sagittal axis was significantly increased in the uncemented knees throughout the investigation period . This corresponded to increased subsidence medially or laterally in the uncemented knees , whereas lift-off was equal in the two groups . Thin ( 8.5 mm ) uncemented tibial components displayed more subsidence than the thicker ones at the medial or lateral edge 3 months after surgery The effect of changes in the articulating surfaces on the kinematics of the Freeman-Samuelson total knee replacement was evaluated . Twenty-two patients ( 22 knees ) ( median age , 69 years ) were r and omized to a st and ard design with a fixed polyethylene bearing , a design with a mobile bearing , or a new design with a spherical medial femoral condyle with a fixed bearing . The patients were studied with radiostereometry and film-exchangers at 0 ° nonweightbearing and during active weightbearing extension from 45 ° to 15 ° . The center of the tibial tray with a mobile-bearing prosthesis occupied a more anterior position than observed in the design s with a fixed bearing . The medial femoral condyle center had a more posterior position in the st and ard design than in the design with a spherical medial condyle . From a distally displaced position at 45 ° , the medial condylar center displaced a mean of 1.8 mm proximally during extension in the st and ard design and had a constant position in the meniscal design . In the spherical design the medial condyle was displaced proximally at 45 ° and displaced a mean of 1.6 mm distally during extension . The reduced anteroposterior and proximodistal translations in the meniscal design are compatible with improved congruency between the components . The design with a spherical medial condyle stabilized anteroposterior motions , but showed more pronounced proximodistal displacement medially than did the other two design The purpose of the current study was to compare midterm outcomes of  posterior cruciate-retaining ( CR ) versus posterior cruciate-substituting ( PS ) procedures using the Genesis II total knee arthroplasty ( TKA ) system ( Smith and Nephew , Memphis , TN ) . Ninety-nine ( 99 ) CR and 93 PS TKA 's were analyzed in this prospect i ve , r and omized clinical trial . Surgeries were performed at seven medical centers by participating surgeons . Clinical outcomes ( Knee Society Score , Range of Motion , WOMAC , SF-12 , and Radiographic Findings ) , in addition to postoperative complications , were evaluated with a minimum follow-up of 5 years . Following data analysis , there were no significant differences in patient demographics or preoperative clinical measures between the two groups . At the latest follow-up interval , no significant differences were found between the CR and PS groups with regards to functional assessment , patient satisfaction , or postoperative complication . However , the PS group did display statistically significant improvements in range of motion when compared with the CR group . The results of this investigation would suggest that , while comparable in regards to supporting good clinical outcomes , the PS Genesis II design does appear to support significantly improved postoperative range of motion when compared with the CR design
target: Finally , with use of a variety of vali date d measures , there was no difference between the two groups in terms of functional status at two , eight , and ten years , regardless of the measure used .
  A less expensive all-polyethylene component as part of a total knee arthroplasty has results equivalent to those obtained with a cemented metal-backed tibial component .
background: BACKGROUND The cost of the implant as part of a total knee arthroplasty accounts for a substantial portion of the costs for the overall procedure : all-polyethylene tibial components cost considerably less than cemented metal-backed tibial components .
  We performed a systematic review of the literature to determine whether the clinical results of lower-cost all-polyethylene tibial components were comparable with the results of a more expensive metal-backed tibial component .