human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 
    Output:
    
agent
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 .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: 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 
    Output:
    