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: Background We have previously reported that 6 months of oral treatment with clodronate reduced the migration of the NexGen total knee prosthesis during the first postoperative year , as measured by  radiostereometry ( RSA ) . We now report the 4-year results . Methods This was a double-blind r and omized study , using RSA with maximal total point motion ( MTPM ) . Results With analysis according to the “ intention to treat ” principle , the only remaining difference between the groups at 4 years was reduced rotation around the transverse axis ( a secondary variable ) in the clodronate group . However , 3 patients ( all clodronate )  did not take any tablet after surgery . If they are excluded , there was an almost statistically significant difference between the groups at 4 years regarding MTPM from baseline , with the clodronate group showing 25 % less migration . From 1 to 4 years , there was no difference in migration rate by MTPM , but there was a continuous increase in rotation around the transverse axis in the controls , which differed from the clodronate group . There were no cases of aseptic loosening . 2 patients had migration of more than 1.3 mm from baseline to 4 years ; neither of them had taken clodronate . The others had migration of less than 0.9 mm . Interpretation Because migration was clearly reduced by clodronate during the first postoperative year , and there was still a difference at 4 years when analyzed per protocol , it appears likely that this treatment can diminish the risk of loosening . The difference in the number of outliers also points in this direction , and may be more relevant than mean migration values BACKGROUND High-flexion total knee arthroplasty was introduced to meet the dem and s of daily activity requiring increased knee flexion . However , concerns have been raised regarding the fixation of high-flexion total knee arthroplasty components and increased rates of loosening have been reported . To date , migration , and thus fixation , of high-flexion total knee arthroplasty components has not been analyzed and the preferential bearing type ( mobile or fixed ) is unknown . METHODS Of eighty-six consecutive eligible patients , seventy-four patients ( seventy-eight knees ) scheduled for total knee arthroplasty were r and omized to one of four  Legacy Posterior Stabilized ( LPS ) total knee prosthesis design s : ( 1 ) LPS-Flex mobile , ( 2 ) LPS-Flex fixed , ( 3 ) LPS mobile , and ( 4 ) LPS fixed . The primary outcome was component migration measured with use of Roentgen stereophotogrammetric analysis , and secondary outcomes were postoperative knee flexion and extension and Knee Society Score . Patients were evaluated postoperatively at six , twelve , twenty-six , and fifty-two weeks and annually thereafter . At the five-year follow-up , eight patients had died and two patients were lost to follow-up . Seventy-seven tibial and forty-two femoral components were suitable for migration measurements . RESULTS The overall five-year migration of the seventy-seven tibial components was not significantly different among the four total knee prosthesis design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.02 to 0.25 mm ) and migration was comparable at the two and five-year follow-up . Migration stabilized in all but three components ( two LPS-Flex mobile and one LPS fixed ) ; one of these components has already been revised and was aseptically loose . The overall five-year migration of the forty-two femoral components was comparable among the four design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.01 to 0.18 mm ) and was similar at two and five years postoperatively . One femoral component ( LPS-Flex mobile ) migrated excessively . In patients who had a mean postoperative flexion of ≥ 125 ° or a maximum flexion of ≥ 135 ° during the one to five-year follow-up period , migration of high-flexion components was comparable with that of conventional components and indicative of appropriate fixation . Postoperative flexion , extension , Knee Society Score , and Knee Society Score function were comparable during the five-year follow-up period and at the two and five-year follow-up . CONCLUSIONS The LPS-Flex total knee prosthesis with either a mobile or a fixed bearing had migration comparable that of with its conventional counterpart and is expected to have similar ( excellent ) long-term survival in these patients . LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence Sixty-two knees ( 60 patients ) were r and omized to four noncemented groups . In Groups 1 , 3 , and 4 , the bone cuts were made with a cooled saw blade . In Group 1 , 15 patients were operated on with the porous coated Osteonic 7000 tibial component . In Group 2 , 15 patients were operated on with the same tibial component as in Group 1 but with the use of a st and ard saw blade . In Group 3 , 16 patients were operated on with the hydroxyapatite-coated Osteonic tibial component , and in Group 4 , 16 patients were operated on with the hydroxyapatite Duracon tibial component . All patients were followed up clinical ly and with roentgenstereometric analysis . There were no differences among the groups regarding clinical outcome . One knee was revised ( Group 2 ) after 1 year because of loosening of the tibial component . The maximum migration at 1 year was 1.7 mm in Group 1 , 1.9 mm in Group 2 , 1.3 mm in Group 3 , and 1 mm in Group 4 . At the 2-year followup , the migrations were 1.8 mm , 1.5 mm , 1.4 mm , and 1 mm in Groups 1 , 2 , 3 , and 4 , respectively . The inducible displacement that occurred at 1 year was 0.6 mm in Group 1 , 0.5 mm in Group 2 , 0.4 mm in Group 3 , and 0.4 mm in Group 4 . The hydroxyapatite coating had a strong positive effect on the tibial component fixation . No prosthesis in the hydroxyapatite groups showed continuous migration OBJECTIVES The objective of this study was to compare the early migration of the cruciate retaining and posterior stabilising versions of the recently introduced Triathlon ™ total knee system , with a view to predicting long term fixation performance . METHODS Sixty patients were prospect ively r and omised to receive either Triathlon ™ posterior stabilised cemented knee prosthesis or Triathlon ™ cruciate retaining cemented knee prosthesis . Tibial component migration was measured by radiostereometric analysis postoperatively and at three months , one year and two years . Clinical outcome was measured by the American Knee Society Score and Knee Osteoarthritis and Injury Outcome Score . RESULTS There were no differences in rotation around the three coordinal axes or in the maximum total point motion ( MTPM ) during the two year follow-up . The posterior stabilised prosthesis had more posterior-anterior translation at three months and one year and more caudal-cranial translation at one year and two years . There were no differences in functional outcome between the groups . CONCLUSION The tibial tray of the Triathlon ™ cemented knee prosthesis showed similar early stability . LEVEL OF EVIDENCE Level I. ARTICLE SUMMARY Article focus : This was a prospect i ve r and omised trial aim ing to compare the single radius posterior stabilised ( PS ) Triathlon ™ total knee arthroplasty ( TKA ) to the cruciate retaining Triathlon ™ TKA system with regard to fixation . Strengths and limitations of this study : Strength of this study was that it is a r and omised prospect i ve trial using an objective measuring tool . The sample size of 25 - 30 patients was reportedly sufficient for the screening of implants using RSA [ 1 ] . TRIAL REGISTRATION Clinical Trials.gov Identifier : NCT00436982 Abstract Objective : Migration of the tibial component in total knee arthroplasty ( TKA ) is subject of many studies using roentgen stereophotogrammetric analysis ( RSA ) . In previous studies of cemented and uncemented tibial components , high migration values were found . Improvements in cementing technique , prosthetic design and pre-coating techniques reduced these values as shown in more recent studies . Material and subjects : A total of 35 patients were initially included in the study and operated on between 12/1999 and 10/2000 . All patients received a NexGen ® TKA cemented into the proximal tibia using Palamed ® G bone cement . The implants and the tibial metaphysis were marked with st and ard tantalum markers . Radiostereometric analysis was performed post-operatively and after 3 , 6 and 12 months using a st and ard digital radiostereometric analysis . Functional parameters were assessed using the Knee Society Score ( KSS ) clinical rating system . Results : There were no complications and failures within the first year . After 1 year radiostereometric measurements of the translational parameters along and the rotational parameters around the x- , y- and z-axis revealed : X-Trans –0.19 mm , Y-Trans + 0.02 mm , Z-Trans + 0.08 mm , X-Rot + 0.26 ° , Y-Rot –0.35 ° , Z-Rot + 0.09 ° . The maximum total point motion was + 0.96 mm and the mean maximum subsidence was –0.23 mm . Except for anterior-posterior , medio-lateral stability and extension leg all endpoints of the KSS clinical rating system showed a significant improvement . Conclusions : After 12 months , the use of Palamed ® G bone cement in total knee arthroplasty was demonstrated to be safe . Both the clinical and radiostereometric results were good and comparable to the results reported in other RSA studies in cemented total knee arthroplasty This single-blinded r and omised controlled trial investigated whether one design of mobile-bearing ( MB ) total knee replacement ( TKR ) has any advantage over a fixed-bearing ( FB ) design on long-term fixation as measured by radiostereometry . The amount of wear underneath the mobile bearing was also evaluated . A series of 42 knees was r and omised to MB or FB tibial components with appropriate polyethylene inserts and followed for between ten and 12 years , or until the death of the patient . The polyethylene in the MB group was superior in that it was gamma-irradiated in inert gas and was calcium-stearate free ; the polyethylene in the FB group was gamma-irradiated in air and contained calcium stearate . In theory this should be advantageous to the wear rate of the MB group . At final follow-up the overall mean migration was 0.75 mm ( SD 0.76 ) in the MB group and 0.66 mm ( SD 0.4 ) in the FB group , with the FB group demonstrating more posterior tilt and the MB group more internal rotation . In the FB group there was one revision for aseptic loosening , but none in the MB group . There were no significant differences in clinical or radiological scores . For the MB group , the mean linear wear rate on the under-surface was 0.026 mm/year ( SD 0.014 ) . This was significantly smaller than the wear rate of 0.11 mm/year ( SD 0.06 ) in the MB between femur and polyethylene ( p < 0.001 ) . Nevertheless , even in a best-case setting the mobile bearings of this TKR design had no apparent advantage in terms of fixation over the FB knee prosthesis at ten to 12 years . The wear underneath the mobile bearing was small and is unlikely to be clinical ly relevant Background The 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 Background and purpose After joint replacement , a repair process starts at the interface between bone and cement . If this process is disturbed , the prosthesis may never become rigidly fixed to the bone , leading to migration— and with time , loosening . Cox-2 inhibitors are widely used as postoperative analgesics , and have adverse effects on bone healing . This could tamper prosthesis fixation . We investigated whether celecoxib , a selective Cox-2 inhibitor , increases prosthesis migration in total knee replacement 
    Output:
    
agent
Cemented and uncemented tibial components had different migration patterns .
For cemented tibial components there was no difference in migration between all-poly and metal-backed components , between mobile bearing and fixed bearing , between cruciate retaining and posterior stabilized .
Furthermore , no difference existed between TKR measured with model-based RSA or marker-based RSA methods .
For uncemented TKR there was some variation in migration with the highest migration for uncoated TKR .
Interpretation - The results from this meta- analysis on  RSA migration of TKR  are in line with both the survival analyses results from joint registries of these TKRs as well as revision rates results from meta-analyses , thus providing further proof for the association between early migration and late revision for loosening .
***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: Background We have previously reported that 6 months of oral treatment with clodronate reduced the migration of the NexGen total knee prosthesis during the first postoperative year , as measured by  radiostereometry ( RSA ) . We now report the 4-year results . Methods This was a double-blind r and omized study , using RSA with maximal total point motion ( MTPM ) . Results With analysis according to the “ intention to treat ” principle , the only remaining difference between the groups at 4 years was reduced rotation around the transverse axis ( a secondary variable ) in the clodronate group . However , 3 patients ( all clodronate )  did not take any tablet after surgery . If they are excluded , there was an almost statistically significant difference between the groups at 4 years regarding MTPM from baseline , with the clodronate group showing 25 % less migration . From 1 to 4 years , there was no difference in migration rate by MTPM , but there was a continuous increase in rotation around the transverse axis in the controls , which differed from the clodronate group . There were no cases of aseptic loosening . 2 patients had migration of more than 1.3 mm from baseline to 4 years ; neither of them had taken clodronate . The others had migration of less than 0.9 mm . Interpretation Because migration was clearly reduced by clodronate during the first postoperative year , and there was still a difference at 4 years when analyzed per protocol , it appears likely that this treatment can diminish the risk of loosening . The difference in the number of outliers also points in this direction , and may be more relevant than mean migration values BACKGROUND High-flexion total knee arthroplasty was introduced to meet the dem and s of daily activity requiring increased knee flexion . However , concerns have been raised regarding the fixation of high-flexion total knee arthroplasty components and increased rates of loosening have been reported . To date , migration , and thus fixation , of high-flexion total knee arthroplasty components has not been analyzed and the preferential bearing type ( mobile or fixed ) is unknown . METHODS Of eighty-six consecutive eligible patients , seventy-four patients ( seventy-eight knees ) scheduled for total knee arthroplasty were r and omized to one of four  Legacy Posterior Stabilized ( LPS ) total knee prosthesis design s : ( 1 ) LPS-Flex mobile , ( 2 ) LPS-Flex fixed , ( 3 ) LPS mobile , and ( 4 ) LPS fixed . The primary outcome was component migration measured with use of Roentgen stereophotogrammetric analysis , and secondary outcomes were postoperative knee flexion and extension and Knee Society Score . Patients were evaluated postoperatively at six , twelve , twenty-six , and fifty-two weeks and annually thereafter . At the five-year follow-up , eight patients had died and two patients were lost to follow-up . Seventy-seven tibial and forty-two femoral components were suitable for migration measurements . RESULTS The overall five-year migration of the seventy-seven tibial components was not significantly different among the four total knee prosthesis design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.02 to 0.25 mm ) and migration was comparable at the two and five-year follow-up . Migration stabilized in all but three components ( two LPS-Flex mobile and one LPS fixed ) ; one of these components has already been revised and was aseptically loose . The overall five-year migration of the forty-two femoral components was comparable among the four design s ( compared with the LPS fixed design , the range of overall mean differences for the other three design s was 0.01 to 0.18 mm ) and was similar at two and five years postoperatively . One femoral component ( LPS-Flex mobile ) migrated excessively . In patients who had a mean postoperative flexion of ≥ 125 ° or a maximum flexion of ≥ 135 ° during the one to five-year follow-up period , migration of high-flexion components was comparable with that of conventional components and indicative of appropriate fixation . Postoperative flexion , extension , Knee Society Score , and Knee Society Score function were comparable during the five-year follow-up period and at the two and five-year follow-up . CONCLUSIONS The LPS-Flex total knee prosthesis with either a mobile or a fixed bearing had migration comparable that of with its conventional counterpart and is expected to have similar ( excellent ) long-term survival in these patients . LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence Sixty-two knees ( 60 patients ) were r and omized to four noncemented groups . In Groups 1 , 3 , and 4 , the bone cuts were made with a cooled saw blade . In Group 1 , 15 patients were operated on with the porous coated Osteonic 7000 tibial component . In Group 2 , 15 patients were operated on with the same tibial component as in Group 1 but with the use of a st and ard saw blade . In Group 3 , 16 patients were operated on with the hydroxyapatite-coated Osteonic tibial component , and in Group 4 , 16 patients were operated on with the hydroxyapatite Duracon tibial component . All patients were followed up clinical ly and with roentgenstereometric analysis . There were no differences among the groups regarding clinical outcome . One knee was revised ( Group 2 ) after 1 year because of loosening of the tibial component . The maximum migration at 1 year was 1.7 mm in Group 1 , 1.9 mm in Group 2 , 1.3 mm in Group 3 , and 1 mm in Group 4 . At the 2-year followup , the migrations were 1.8 mm , 1.5 mm , 1.4 mm , and 1 mm in Groups 1 , 2 , 3 , and 4 , respectively . The inducible displacement that occurred at 1 year was 0.6 mm in Group 1 , 0.5 mm in Group 2 , 0.4 mm in Group 3 , and 0.4 mm in Group 4 . The hydroxyapatite coating had a strong positive effect on the tibial component fixation . No prosthesis in the hydroxyapatite groups showed continuous migration OBJECTIVES The objective of this study was to compare the early migration of the cruciate retaining and posterior stabilising versions of the recently introduced Triathlon ™ total knee system , with a view to predicting long term fixation performance . METHODS Sixty patients were prospect ively r and omised to receive either Triathlon ™ posterior stabilised cemented knee prosthesis or Triathlon ™ cruciate retaining cemented knee prosthesis . Tibial component migration was measured by radiostereometric analysis postoperatively and at three months , one year and two years . Clinical outcome was measured by the American Knee Society Score and Knee Osteoarthritis and Injury Outcome Score . RESULTS There were no differences in rotation around the three coordinal axes or in the maximum total point motion ( MTPM ) during the two year follow-up . The posterior stabilised prosthesis had more posterior-anterior translation at three months and one year and more caudal-cranial translation at one year and two years . There were no differences in functional outcome between the groups . CONCLUSION The tibial tray of the Triathlon ™ cemented knee prosthesis showed similar early stability . LEVEL OF EVIDENCE Level I. ARTICLE SUMMARY Article focus : This was a prospect i ve r and omised trial aim ing to compare the single radius posterior stabilised ( PS ) Triathlon ™ total knee arthroplasty ( TKA ) to the cruciate retaining Triathlon ™ TKA system with regard to fixation . Strengths and limitations of this study : Strength of this study was that it is a r and omised prospect i ve trial using an objective measuring tool . The sample size of 25 - 30 patients was reportedly sufficient for the screening of implants using RSA [ 1 ] . TRIAL REGISTRATION Clinical Trials.gov Identifier : NCT00436982 Abstract Objective : Migration of the tibial component in total knee arthroplasty ( TKA ) is subject of many studies using roentgen stereophotogrammetric analysis ( RSA ) . In previous studies of cemented and uncemented tibial components , high migration values were found . Improvements in cementing technique , prosthetic design and pre-coating techniques reduced these values as shown in more recent studies . Material and subjects : A total of 35 patients were initially included in the study and operated on between 12/1999 and 10/2000 . All patients received a NexGen ® TKA cemented into the proximal tibia using Palamed ® G bone cement . The implants and the tibial metaphysis were marked with st and ard tantalum markers . Radiostereometric analysis was performed post-operatively and after 3 , 6 and 12 months using a st and ard digital radiostereometric analysis . Functional parameters were assessed using the Knee Society Score ( KSS ) clinical rating system . Results : There were no complications and failures within the first year . After 1 year radiostereometric measurements of the translational parameters along and the rotational parameters around the x- , y- and z-axis revealed : X-Trans –0.19 mm , Y-Trans + 0.02 mm , Z-Trans + 0.08 mm , X-Rot + 0.26 ° , Y-Rot –0.35 ° , Z-Rot + 0.09 ° . The maximum total point motion was + 0.96 mm and the mean maximum subsidence was –0.23 mm . Except for anterior-posterior , medio-lateral stability and extension leg all endpoints of the KSS clinical rating system showed a significant improvement . Conclusions : After 12 months , the use of Palamed ® G bone cement in total knee arthroplasty was demonstrated to be safe . Both the clinical and radiostereometric results were good and comparable to the results reported in other RSA studies in cemented total knee arthroplasty This single-blinded r and omised controlled trial investigated whether one design of mobile-bearing ( MB ) total knee replacement ( TKR ) has any advantage over a fixed-bearing ( FB ) design on long-term fixation as measured by radiostereometry . The amount of wear underneath the mobile bearing was also evaluated . A series of 42 knees was r and omised to MB or FB tibial components with appropriate polyethylene inserts and followed for between ten and 12 years , or until the death of the patient . The polyethylene in the MB group was superior in that it was gamma-irradiated in inert gas and was calcium-stearate free ; the polyethylene in the FB group was gamma-irradiated in air and contained calcium stearate . In theory this should be advantageous to the wear rate of the MB group . At final follow-up the overall mean migration was 0.75 mm ( SD 0.76 ) in the MB group and 0.66 mm ( SD 0.4 ) in the FB group , with the FB group demonstrating more posterior tilt and the MB group more internal rotation . In the FB group there was one revision for aseptic loosening , but none in the MB group . There were no significant differences in clinical or radiological scores . For the MB group , the mean linear wear rate on the under-surface was 0.026 mm/year ( SD 0.014 ) . This was significantly smaller than the wear rate of 0.11 mm/year ( SD 0.06 ) in the MB between femur and polyethylene ( p < 0.001 ) . Nevertheless , even in a best-case setting the mobile bearings of this TKR design had no apparent advantage in terms of fixation over the FB knee prosthesis at ten to 12 years . The wear underneath the mobile bearing was small and is unlikely to be clinical ly relevant Background The 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 Background and purpose After joint replacement , a repair process starts at the interface between bone and cement . If this process is disturbed , the prosthesis may never become rigidly fixed to the bone , leading to migration— and with time , loosening . Cox-2 inhibitors are widely used as postoperative analgesics , and have adverse effects on bone healing . This could tamper prosthesis fixation . We investigated whether celecoxib , a selective Cox-2 inhibitor , increases prosthesis migration in total knee replacement 
    Output:
    