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: Medium- and long-term results from  cemented total hip arthroplasty ( THA ) in patients with rheumatoid arthritis ( RA ) show a higher incidence of infection and aseptic loosening when compared to other diagnoses . Early results using uncemented prostheses are variable . Hydroxyapatite ( HA ) coatings are thought to improve early osseointegration in uncemented THA . In a prospect i ve , international , multicenter clinical study , 32 RA patients who received 33 uncemented HA-coated prostheses  were followed up for a minimum of 5 years . Medium-term clinical results are excellent . No infection or aseptic loosening has been recorded . Excellent osseointegration was observed radiographically . Bone remodeling was consistent with mainly proximal to midstem stress transfer . We conclude that uncemented , proximally HA-coated prostheses are a promising alternative to cemented prostheses for RA patients We review ed the records of the long-term outcome of 208 Charnley and 982 Stanmore total hip replacements ( THR ) performed by or under the supervision of one surgeon from 1973 to 1987 . The Stanmore implant had a better survival rate before revision at 14 years ( 86 % to 79 % , p = 0.004 ) , but the difference only became apparent at ten years . The later Stanmore implants did better than the early ones ( 97 % to 92 % at ten years , p = 0.005 ) , the improvement coinciding with the introduction of a new cementing technique using a gun . Most of the Charnley implants were done before most of the Stanmore implants so that the difference between the results may in part be explained by improved methods , but this is not the complete explanation since a difference persisted for implants carried out during the same period of time . We conclude that improved techniques have reduced failure rates substantially . This improvement was much greater than that observed between these two design s of implant . Proof of the difference would require a very large r and omised controlled trial over a ten-year period This article presents a prospect i ve clinical and radiologic review of 55 total hip replacements in 50 patients in which the cementless Harris-Galante porous-coated acetabular component was used . All patients were 50 years of age or younger . The cups were inserted by 15 different surgeons . The minimum followup was 5 years , with a mean of 7 years . No acetabular component has been revised for loosening , and none have migrated . Three ( 5.5 % ) cups have progressive bone-component radiolucent lines , two ( 3.6 % ) of which are complete . Six ( 10.9 % ) acetabular liners have been replaced for excessive polyethylene wear , and an additional four ( 7.3 % ) show sufficient wear to produce obvious radiographic eccentricity of the femoral head . All of the revised liners had 32-mm femoral heads and an initial polyethylene thickness of less than 6 mm . Although the results reflect excellent fixation of this component in the medium term , the incidence of exchange of the polyethylene liner for excessive wear is unacceptably high . The reduction in polyethylene thickness associated with the use of a metal-backed component and a 32-mm articulation was one of the factors contributing to the accelerated wear patterns seen in this series A total of 410 hips were r and omized to treatment with either a Charnley ( 206 hips ) or a Spectron ( 204 hips ) total hip arthroplasty .  The patients were operated on by a st and ardized procedure using a contemporary cementing technique and were followed after 1 , 3 , 5 to 6 , and 10 years . The postoperative radiographs showed a significantly increased rate of malalignment and consequently low grade of cement mantle quality of the Charnley stem compared to the Spectron . No differences concerning cement mantle quality or positioning were found between the Charnley ogee cup and the metal-backed Spectron . Evaluation of the follow-up radiographs revealed 10 loose Charnley stems and 1 loose Spectron stem and 4 loose Charnley ogee cups and 23 loose Spectron metal-backed cups . The differences of revision rate for the femoral and acetabular components of the 2 prostheses were significant ( P = .03 , Charnley femoral component more frequent ; P = .03 , Spectron acetabular component more frequent ) . The radiographic evaluation strengthened this disparity . Poor wear characteristics of the metal-backed Spectron cup are perhaps the main reason for the highly significant difference in mechanical failure rate between the 2 cups . We therefore propose that metal-backing of cemented cups should be avoided , at least when combined with larger femoral heads . The difficulty in positioning the Charnley stem with an adequate cement mantle , especially in the absence of trochanteric osteotomy , might explain the inferior Charnley stem longevity in this study 155 patients ( 171 hips ) with a mean age of 50 years ( 24 - 64 ) were r and omized to uncemented PCA ( 84 hips ) or Harris-Galante type I ( 87 hips ) total hip arthroplasty .  Clinical and radiographic evaluations were done regularly . The improvements in the Harris hip and pain scores did not differ . Osteolysis developed in 5 PCA and 17 Harris-Galante hips . 13 hips in the PCA and 16 in the Harris-Galante ( HG ) group were revised because of mechanical failures and 1 hip ( HG ) because of infection after a mean follow-up of 9 years . Decreased 10-year survival rate , based on revision as end-point , was noted for the PCA ( 85 % ) , compared with the Harris-Galante cup ( 99 % ) . The corresponding survival rate of the PCA stem ( 96 % ) was higher than that observed for the Harris-Galante design ( 86 % ) . When radiographic failures were included , the survival rates of the 4 different components dropped to between 73 % and 94 % . These findings indicate that further revisions will be necessary and continuous radiographic follow-up is indicated to enable revision before severe bone destruction has occurred . Although the PCA and the Harris-Galante design s differed as regards the survival of the individual components , the overall clinical and radiographic survival rates of these cementless total hip arthroplasties were poor One hundred and twenty-nine consecutive cementless primary total hip arthroplasties with Zweymüller-Alloclassic grit-blasted titanium components  were evaluated prospect ively at an average follow-up of 5.9 years . The clinical results were grade d as excellent or good in 116 hips ( 90 % ) , fair in 12 , and poor in one due to a fracture of the femoral shaft at operation leading to early stem loosening and delayed ring loosening . Failure was defined as definite aseptic loosening , and the final survivorship at 8 years was 99.3 % for the SL-stem , and 99.1 % for the CSF-threaded cup . These early results compare favourably with those of total hip arthroplasties using new cementing techniques A r and omized , concurrently controlled , prospect i ve , single-blinded , multicenter study was done to evaluate the effect of proximal surface coating of a femoral prosthesis on clinical and radiographic results of  cementless total hip arthroplasty ( THA ) .  The Profile femoral prosthesis ( DePuy , Warsaw , IN ) , an anatomic titanium alloy stem , was used in one of three configurations : ( 1 ) smooth , ( 2 ) porous coated , or ( 3 ) hydroxyapatite ( HA ) coated .  Ninety-one cases were enrolled in the study , with seven cases lost to follow-up and 79 cases available for clinical review with 24- to 48-month follow-up . The study shows that HA-coated stems performed as well , if not better than , porous-coated or smooth stems . Results show HA-costed stems with statistically superior total Harris hip scores ( microHA = 96.0 ) than smooth stems ( microS = 85.1 ) ( Student 's t-test , P = 0.004 ) . This was primarily due to differences between the functional score of the two groups ( microHA - 31.6 ; microS = 27.9 , P = 0.003 ) . Porous-coated stems were intermediate in performance ( microPC = 89.8 ) , with hip scores that were statistically indistinguishable from both smooth and HA-coated stems . Our data support the hypothesis that clinical differences exist and are attributable to the type of surface coating used for the cementless femoral components in THA Between January 1988 and January 1991 we performed 100 consecutive cemented total hip replacements using a zirconia head , a titanium alloy stem and a polyethylene cup .  We review ed 78 of these hips in 61 patients in detail at a mean of 5.8 years ( 1 to 9 ) . Aseptic loosening was seen in 11 hips ( 14 % ) . Eight needed revision . In total , 37 cups ( 47.5 % ) showed radiolucent lines , all at the cement-bone interface , with 18 ( 23 % ) involving all the interface . Of the 78 femoral implants , 17 ( 21.7 % ) showed radiolucent lines , and two , which had a complete line of more than 1 mm thick , definite endocortical osteolyses . There was also an abnormally high incidence of osteolysis of more than 2 mm at the calcar . Survivorship analysis showed that only 63 % were in situ at eight years . These worrying results led us to ab and on the use of zirconia heads , since at the same hospital , using the same femoral stem , cement and polyethylene cup , but with alumina femoral heads , the survival rate was 93 % at nine years . We discuss the possible reasons for the poor performance of zirconia ceramic Seventy primary total hip arthroplasties using the Harris-Galante acetabular cup ( Zimmer , Warsaw , IN ) were prospect ively examined . Over the entire period of 65.4+/-7.8 months ,  radiologic migration analysis  was performed using the  Einbildroentgenanalyse  ( EBRA ) method at an accuracy of 1 mm . Although there was clinical ly no suspicion of prosthetic loosening in any case , in 8 implants ( 11.4 % ) migration of more than 1 mm was observed . Cranial migration occurred in 3 cases ( 1.1 , 1.3 and 1.6 mm ) , medial migration in 3 cases ( 1.1 , 1.1 , and 2.9 mm ) , and lateral migration in 2 cases ( 1.1 and 1.1 mm ) . In the other 62 cases , however , no migration was traceable . Compared with measurements of other implant systems by means of the EBRA method published recently by other groups , the migration rate of the Harris-Galante cup was without exception lower and provided excellent midterm implant stability One hundred and eighty-four patients who had been managed , between 1984 and 1985 , with a total of 204 consecutive primary total hip arthroplasties with insertion of a Harris-Galante type-I acetabular component without cement were prospect ively studied . There were eighty-two men ( 45 per cent ) and 102 women ( 55 per cent ) . The mean age at the time of the operation was fifty-two years ( range , twenty to eighty-four years ) . One hundred and fifty-seven patients ( 173 hips ) were available for clinical review at a mean of 104 months ( range , seventy-eight to 126 months ) . At this time , the mean preoperative Harris hip score of 52 points ( range , 12 to 79 points ) had improved to a mean of 90 points ( range , 44 to 100 points ) . Two patients ( two hips ) had had an exchange of an excessively worn polyethylene liner . One patient ( one hip ) had had débridement and grafting of an area of massive retroacetabular osteolysis . Two stable acetabular components ( 1 per cent ) had been revised at the time of femoral revision . None of the cups had been revised because of aseptic loosening . Radiographic examination of 150 patients ( 165 hips ) at a mean of 104 months ( range , seventy-eight to 126 months ) revealed that 156 cups ( 95 per cent ) were stable . Eight cups ( 5 per cent ) were considered to be possibly unstable , with a radiolucent line between the prosthesis and the bone that was one millimeter wide or less in at least four of five zones ; two of the eight had a complete radiolucent line in all zones . One component , which had been implanted with a bulk allograft from a femoral head , migrated more than two millimeters in the first two years and then stabilized without complication . Osteolysis was seen in seven acetabula ( 4 per cent ) and was limited to the periphery of the cup in six . Survivorship analysis at ten years revealed that the acetabular component had a 99 per cent chance of survival ( 95 per cent confidence interval , 0.98 to 1.0 ) with revision or aseptic loosening as the end point and a 97 per cent chance of survival ( 95 per cent confidence interval , 0.95 to 1.0 ) with revision , aseptic loosening , or reoperation because of a problem related to the acetabular component as the end point A proximally hydroxyapatite (HA)-coated hip prosthesis design ed for proximal stem bonding and stress transfer was studied in a consecutive series of 398 patients in an ongoing , prospect i ve multicenter study . Follow-up was 
    Output:
    
agent
The Charnley prosthesis had by far the best and most comprehensive evidence base with better than 90 % implant survival after about 10 years .
Some uncemented stems have shown promising medium-term outcome , but no combination of uncemented cup and stem fulfilled the benchmark criterion of > or = 90 % implant survival at 10 years , which we propose as a minimum requirement for unrestricted clinical use for prostheses used in primary THR .
***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: Medium- and long-term results from  cemented total hip arthroplasty ( THA ) in patients with rheumatoid arthritis ( RA ) show a higher incidence of infection and aseptic loosening when compared to other diagnoses . Early results using uncemented prostheses are variable . Hydroxyapatite ( HA ) coatings are thought to improve early osseointegration in uncemented THA . In a prospect i ve , international , multicenter clinical study , 32 RA patients who received 33 uncemented HA-coated prostheses  were followed up for a minimum of 5 years . Medium-term clinical results are excellent . No infection or aseptic loosening has been recorded . Excellent osseointegration was observed radiographically . Bone remodeling was consistent with mainly proximal to midstem stress transfer . We conclude that uncemented , proximally HA-coated prostheses are a promising alternative to cemented prostheses for RA patients We review ed the records of the long-term outcome of 208 Charnley and 982 Stanmore total hip replacements ( THR ) performed by or under the supervision of one surgeon from 1973 to 1987 . The Stanmore implant had a better survival rate before revision at 14 years ( 86 % to 79 % , p = 0.004 ) , but the difference only became apparent at ten years . The later Stanmore implants did better than the early ones ( 97 % to 92 % at ten years , p = 0.005 ) , the improvement coinciding with the introduction of a new cementing technique using a gun . Most of the Charnley implants were done before most of the Stanmore implants so that the difference between the results may in part be explained by improved methods , but this is not the complete explanation since a difference persisted for implants carried out during the same period of time . We conclude that improved techniques have reduced failure rates substantially . This improvement was much greater than that observed between these two design s of implant . Proof of the difference would require a very large r and omised controlled trial over a ten-year period This article presents a prospect i ve clinical and radiologic review of 55 total hip replacements in 50 patients in which the cementless Harris-Galante porous-coated acetabular component was used . All patients were 50 years of age or younger . The cups were inserted by 15 different surgeons . The minimum followup was 5 years , with a mean of 7 years . No acetabular component has been revised for loosening , and none have migrated . Three ( 5.5 % ) cups have progressive bone-component radiolucent lines , two ( 3.6 % ) of which are complete . Six ( 10.9 % ) acetabular liners have been replaced for excessive polyethylene wear , and an additional four ( 7.3 % ) show sufficient wear to produce obvious radiographic eccentricity of the femoral head . All of the revised liners had 32-mm femoral heads and an initial polyethylene thickness of less than 6 mm . Although the results reflect excellent fixation of this component in the medium term , the incidence of exchange of the polyethylene liner for excessive wear is unacceptably high . The reduction in polyethylene thickness associated with the use of a metal-backed component and a 32-mm articulation was one of the factors contributing to the accelerated wear patterns seen in this series A total of 410 hips were r and omized to treatment with either a Charnley ( 206 hips ) or a Spectron ( 204 hips ) total hip arthroplasty .  The patients were operated on by a st and ardized procedure using a contemporary cementing technique and were followed after 1 , 3 , 5 to 6 , and 10 years . The postoperative radiographs showed a significantly increased rate of malalignment and consequently low grade of cement mantle quality of the Charnley stem compared to the Spectron . No differences concerning cement mantle quality or positioning were found between the Charnley ogee cup and the metal-backed Spectron . Evaluation of the follow-up radiographs revealed 10 loose Charnley stems and 1 loose Spectron stem and 4 loose Charnley ogee cups and 23 loose Spectron metal-backed cups . The differences of revision rate for the femoral and acetabular components of the 2 prostheses were significant ( P = .03 , Charnley femoral component more frequent ; P = .03 , Spectron acetabular component more frequent ) . The radiographic evaluation strengthened this disparity . Poor wear characteristics of the metal-backed Spectron cup are perhaps the main reason for the highly significant difference in mechanical failure rate between the 2 cups . We therefore propose that metal-backing of cemented cups should be avoided , at least when combined with larger femoral heads . The difficulty in positioning the Charnley stem with an adequate cement mantle , especially in the absence of trochanteric osteotomy , might explain the inferior Charnley stem longevity in this study 155 patients ( 171 hips ) with a mean age of 50 years ( 24 - 64 ) were r and omized to uncemented PCA ( 84 hips ) or Harris-Galante type I ( 87 hips ) total hip arthroplasty .  Clinical and radiographic evaluations were done regularly . The improvements in the Harris hip and pain scores did not differ . Osteolysis developed in 5 PCA and 17 Harris-Galante hips . 13 hips in the PCA and 16 in the Harris-Galante ( HG ) group were revised because of mechanical failures and 1 hip ( HG ) because of infection after a mean follow-up of 9 years . Decreased 10-year survival rate , based on revision as end-point , was noted for the PCA ( 85 % ) , compared with the Harris-Galante cup ( 99 % ) . The corresponding survival rate of the PCA stem ( 96 % ) was higher than that observed for the Harris-Galante design ( 86 % ) . When radiographic failures were included , the survival rates of the 4 different components dropped to between 73 % and 94 % . These findings indicate that further revisions will be necessary and continuous radiographic follow-up is indicated to enable revision before severe bone destruction has occurred . Although the PCA and the Harris-Galante design s differed as regards the survival of the individual components , the overall clinical and radiographic survival rates of these cementless total hip arthroplasties were poor One hundred and twenty-nine consecutive cementless primary total hip arthroplasties with Zweymüller-Alloclassic grit-blasted titanium components  were evaluated prospect ively at an average follow-up of 5.9 years . The clinical results were grade d as excellent or good in 116 hips ( 90 % ) , fair in 12 , and poor in one due to a fracture of the femoral shaft at operation leading to early stem loosening and delayed ring loosening . Failure was defined as definite aseptic loosening , and the final survivorship at 8 years was 99.3 % for the SL-stem , and 99.1 % for the CSF-threaded cup . These early results compare favourably with those of total hip arthroplasties using new cementing techniques A r and omized , concurrently controlled , prospect i ve , single-blinded , multicenter study was done to evaluate the effect of proximal surface coating of a femoral prosthesis on clinical and radiographic results of  cementless total hip arthroplasty ( THA ) .  The Profile femoral prosthesis ( DePuy , Warsaw , IN ) , an anatomic titanium alloy stem , was used in one of three configurations : ( 1 ) smooth , ( 2 ) porous coated , or ( 3 ) hydroxyapatite ( HA ) coated .  Ninety-one cases were enrolled in the study , with seven cases lost to follow-up and 79 cases available for clinical review with 24- to 48-month follow-up . The study shows that HA-coated stems performed as well , if not better than , porous-coated or smooth stems . Results show HA-costed stems with statistically superior total Harris hip scores ( microHA = 96.0 ) than smooth stems ( microS = 85.1 ) ( Student 's t-test , P = 0.004 ) . This was primarily due to differences between the functional score of the two groups ( microHA - 31.6 ; microS = 27.9 , P = 0.003 ) . Porous-coated stems were intermediate in performance ( microPC = 89.8 ) , with hip scores that were statistically indistinguishable from both smooth and HA-coated stems . Our data support the hypothesis that clinical differences exist and are attributable to the type of surface coating used for the cementless femoral components in THA Between January 1988 and January 1991 we performed 100 consecutive cemented total hip replacements using a zirconia head , a titanium alloy stem and a polyethylene cup .  We review ed 78 of these hips in 61 patients in detail at a mean of 5.8 years ( 1 to 9 ) . Aseptic loosening was seen in 11 hips ( 14 % ) . Eight needed revision . In total , 37 cups ( 47.5 % ) showed radiolucent lines , all at the cement-bone interface , with 18 ( 23 % ) involving all the interface . Of the 78 femoral implants , 17 ( 21.7 % ) showed radiolucent lines , and two , which had a complete line of more than 1 mm thick , definite endocortical osteolyses . There was also an abnormally high incidence of osteolysis of more than 2 mm at the calcar . Survivorship analysis showed that only 63 % were in situ at eight years . These worrying results led us to ab and on the use of zirconia heads , since at the same hospital , using the same femoral stem , cement and polyethylene cup , but with alumina femoral heads , the survival rate was 93 % at nine years . We discuss the possible reasons for the poor performance of zirconia ceramic Seventy primary total hip arthroplasties using the Harris-Galante acetabular cup ( Zimmer , Warsaw , IN ) were prospect ively examined . Over the entire period of 65.4+/-7.8 months ,  radiologic migration analysis  was performed using the  Einbildroentgenanalyse  ( EBRA ) method at an accuracy of 1 mm . Although there was clinical ly no suspicion of prosthetic loosening in any case , in 8 implants ( 11.4 % ) migration of more than 1 mm was observed . Cranial migration occurred in 3 cases ( 1.1 , 1.3 and 1.6 mm ) , medial migration in 3 cases ( 1.1 , 1.1 , and 2.9 mm ) , and lateral migration in 2 cases ( 1.1 and 1.1 mm ) . In the other 62 cases , however , no migration was traceable . Compared with measurements of other implant systems by means of the EBRA method published recently by other groups , the migration rate of the Harris-Galante cup was without exception lower and provided excellent midterm implant stability One hundred and eighty-four patients who had been managed , between 1984 and 1985 , with a total of 204 consecutive primary total hip arthroplasties with insertion of a Harris-Galante type-I acetabular component without cement were prospect ively studied . There were eighty-two men ( 45 per cent ) and 102 women ( 55 per cent ) . The mean age at the time of the operation was fifty-two years ( range , twenty to eighty-four years ) . One hundred and fifty-seven patients ( 173 hips ) were available for clinical review at a mean of 104 months ( range , seventy-eight to 126 months ) . At this time , the mean preoperative Harris hip score of 52 points ( range , 12 to 79 points ) had improved to a mean of 90 points ( range , 44 to 100 points ) . Two patients ( two hips ) had had an exchange of an excessively worn polyethylene liner . One patient ( one hip ) had had débridement and grafting of an area of massive retroacetabular osteolysis . Two stable acetabular components ( 1 per cent ) had been revised at the time of femoral revision . None of the cups had been revised because of aseptic loosening . Radiographic examination of 150 patients ( 165 hips ) at a mean of 104 months ( range , seventy-eight to 126 months ) revealed that 156 cups ( 95 per cent ) were stable . Eight cups ( 5 per cent ) were considered to be possibly unstable , with a radiolucent line between the prosthesis and the bone that was one millimeter wide or less in at least four of five zones ; two of the eight had a complete radiolucent line in all zones . One component , which had been implanted with a bulk allograft from a femoral head , migrated more than two millimeters in the first two years and then stabilized without complication . Osteolysis was seen in seven acetabula ( 4 per cent ) and was limited to the periphery of the cup in six . Survivorship analysis at ten years revealed that the acetabular component had a 99 per cent chance of survival ( 95 per cent confidence interval , 0.98 to 1.0 ) with revision or aseptic loosening as the end point and a 97 per cent chance of survival ( 95 per cent confidence interval , 0.95 to 1.0 ) with revision , aseptic loosening , or reoperation because of a problem related to the acetabular component as the end point A proximally hydroxyapatite (HA)-coated hip prosthesis design ed for proximal stem bonding and stress transfer was studied in a consecutive series of 398 patients in an ongoing , prospect i ve multicenter study . Follow-up was 
    Output:
    