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: We selected r and omly a consecutive series of 162 patients requiring hip replacement to receive either a cementless , hemispherical , modular , titanium acetabular cup or a cemented , all-polyethylene cup . These replacements were performed by two surgeons in four general hospitals . The same surgical technique was used and a 26 mm metal-head femoral component was used in every case . After exclusions , 115 hips were studied for differences in rates of wear and osteolysis . The mean clinical follow-up was eight years and the mean radiological follow-up , 6.5 years . The cementless cups  wore at a mean rate of 0.15 mm per year and the cemented cups at 0.07 mm per year . This difference was significant ( p < 0.0001 ) . Our findings in this mid-term study suggest that cementless cups  wear more than cemented cups We studied prospect ively the long-term results of the Charnley Elite-Plus femoral stem in 184 consecutive young patients ( 194 hips ) . There were 130 men and 54 women with a mean age of 49.1 years ( 21 to 60 ) . The predominant diagnosis was osteonecrosis of the femoral head ( 63.6 % , 117 patients ) .  Clinical and radiological evaluation was undertaken at each follow-up . The mean follow-up was 11.2 years ( 10 to 12 ) . The mean pre-operative Harris hip score was 43.4 ( 12 to 49 ) which improved to 91 ( 59 to 100 ) at the final follow-up . The survival of the femoral stem  at 12 years was 99 % with revision as the end-point . The mean annual linear wear of the polyethylene liner was 0.17 mm ( 0.13 to 0.22 ) . The prevalence of acetabular osteolysis was 10.8 % ( 21 hips ) and osteolysis of the calcar femorale 12.9 % ( 25 hips ) . A third-generation cementing technique , accurate alignment of the stem and the use of a 22 mm zirconia head were important factors in the prevention of aseptic loosening of the Elite Plus femoral stem in these high-risk young patients Background : We previously reported our two and five‐year results of arthroplasty with the Porous Coated Anatomic total hip prosthesis . We now report on the performance of this prosthesis at ten to fourteen years . Methods : The results of 311 total hip replacements in which a Porous Coated Anatomic prosthesis was inserted without cement in 279 patients were analyzed prospect ively . The average age of the patients at the time of the replacement was sixty-one years ( range , twenty to eighty‐one years ) . Sixty‐four patients ( seventy-six hips ) died postoperatively . Forty‐five patients ( forty‐seven hips ) were lost to follow‐up , and four were excluded because of their medical condition . One hundred and sixty‐eight patients ( 187 hips ) were followed for ten to fourteen years ( average , twelve years ) . Seventeen of those patients ( seventeen hips ) had a revision . Results : The overall survival rate ( with any revision as the end point ) was 90.0 % ± 5.4 % at fourteen years , with an average Harris hip score of 85 ± 14 points . The prevalence of thigh pain was 36 % ( fifty-six of 157 ) in the late period ( more than ten years postoperatively ) . Radiographs showed stable fixation , with bone ingrowth , of 83 % ( 130 ) of the 156 acetabular components and 88 % ( 137 ) of the 156 femoral components at the latest follow‐up evaluation . Men had a significantly higher rate of femoral osteolysis than did women ( p < 0.001 ) . The rates of acetabular and femoral osteolysis associated with 32‐mm femoral heads ( 49 % [ twenty-three ] of forty-seven and 70 % [ thirty-three ] of forty-seven , respectively ) were significantly higher ( p < 0.01 ) than those associated with 26‐mm heads ( 26 % [ twenty-eight ] of 109 and 30 % [ thirty-three ] of 109 , respectively ) . Despite this , revision ( removal or exchange of components ) was not directly related to head size ; instead , it was related to polyethylene thickness . Conclusions : There have been persistent problems with the Porous Coated Anatomic hip system , including thigh pain and an increasing prevalence of osteolysis with time . Revision because of aseptic loosening was related more to the thickness of the polyethylene liner than to the size of the femoral head . Femoral heads with a 32-mm diameter did not increase the risk for revision provided that an adequate thickness of polyethylene had been used Background Even though there are multiple studies documenting the outcome of the Charnley low-friction arthroplasty as well as abundant studies on uncemented arthroplasties , there is a dearth of comparative studies of the uncemented acetabular component and a cemented component . In this study we aim ed to document the long-term clinical and radiographic outcome as well as component survival in a r and omized controlled trial . Material s and methods Two hundred fifteen patients ( 240 hips ) were r and omly allocated to receive a cemented Charnley cup or uncemented Duraloc 1200 cup . All patients received cemented Charnley stems and were evaluated clinical ly and radiographically after 6 months , and 2 , 5 , and 10 years . Results Harris Hip Scores improved from 48.3 [ 95 % confidence interval ( CI ) 45.0–51.6 ] to 90.2 [ 95 % CI 87.9–92.6 ] in the Charnley group and from 49.3 [ 95 % CI 86.9–91.3 ] in the Duraloc group at 6 months . After 10 years , the Charnley group ’s Harris Hip Score was 89.8 [ 95 % confidence interval ( CI ) 87.0–92.6 ] , and the Duraloc group ’s score was 87.3 ( 95 % CI 84.1–90.6 ) . In the radiographic analysis after 10 years , there was no statistical difference in the prevalence of radiographic signs of loosening . Nine cups were revised in the Charnley group , and five cups were removed in the Duraloc group . The difference was not statistically significant . There was no statistical difference between the cups when aseptic loosening was the end-point , nor in survival analyses . Conclusions There is no statistically significant difference in clinical or radiological outcome between the Charnley cup and the Duraloc after 10 years , and no difference in implant survival after 12–14 years . The uncemented Duraloc cup is as good as the cemented Charnley cup after 10 years Abstract : The purpose of this study was to up date the results of a prospect i ve series of primary cementless total hip arthroplasties  after a minimum of fifteen years of follow-up . It is one of the first studies of cementless total hip arthroplasties followed for a minimum of fifteen years . One hundred consecutive Porous Coated Anatomic ( PCA ) total hip replacements were implanted between October 1983 and January 1986 . Fifty-five patients ( sixty-four hips ) that were alive at a minimum of fifteen years postoperatively are the focus of the present study . At this time of follow-up , at an average of 15.6 years ( range , fifteen to seventeen years ) after the total hip arthroplasty , 17 % ( seventeen hips ) of the entire cohort and 23 % ( fifteen hips ) of the living cohort had undergone revision because of loosening of the acetabular component or osteolysis . Seven percent ( seven hips ) of the entire cohort and 6 % ( four hips ) of the living cohort had undergone revision for loosening of the femoral component or osteolysis . Only four femoral stems had been revised for isolated loosening ( without osteolysis).The  PCA femoral component proved to be durable at a minimum of fifteen years postoperatively , while the acetabular component was less durable . Level of Evidence : Therapeutic study , Level IV ( case series [ no , or historical , control group ] ) . See Instructions to Authors for a complete description of levels of evidence We enrolled 98 patients ( 107 hips ) with a mean age of 47 years ( SD 8.6 ) into a prospect i ve study of the Madreporic Lord THR ; 34 hips had primary and 73 secondary osteoarthritis . After ten years , the survival rate using revision as the endpoint for failure was 70 % ( + /-9 ) for the cup and 98 % ( + /-0.3 ) for the stem . The combined clinical and radiological survival rates were 46 % ( + /-11 ) and 81 % ( + /-10 ) , respectively . Osteoporosis due to stress-shielding was observed in the proximal femur . Hips with radiologically dense bone postoperatively showed the most pronounced bone loss . We recommend continued radiological follow-up of patients with this type of implant to allow revision to be performed before there is severe bony destruction of the pelvis In a prospect i ve study , 93 unselected consecutive uncemented hip arthroplasties were performed in 80 patients using the  titanium-coated RM acetabular component and the CLS femoral component .  The mean age of the patients at operation was 52 years ( 28 to 81 ) . None were lost to follow-up . In the 23 patients who had died ( 26 hips ) only one acetabular component had been revised . In the 57 living patients ( 67 hips ) , 13 such revisions had been performed . Of the 14 revisions , seven were for osteolysis , five for loosening and two for infection . Survival analysis of this implant showed a total probability of survival of 83 % ( 95 % confidence interval 73 to 90 ) , with all revisions as the endpoint , and a probability of 94 % ( 95 % confidence interval 87 to 98 ) with revision for aseptic loosening as the endpoint , indicating reliable long-term fixation of the titanium-coated RM acetabular component The purpose of the current study was to up date the results of a prospect i ve , single-surgeon series of primary Charnley total hip arthroplasties performed with cement . This investigation is one of the first studies in which hips treated with total hip arthroplasty with cement  were followed for a minimum of thirty years . Twenty-seven patients ( thirty-four [ 10.3 % ] of the hips in the initial study group ) were alive at a minimum of thirty years postoperatively . These patients served as the focus of the present study .  Revision because of aseptic loosening of the acetabular component was performed in 7.3 % ( twenty-three ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 26 % ( eight ) of the hips in the living cohort .  Revision  because of aseptic loosening of the femoral component was performed in 3.2 % ( ten ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 10 % ( three ) of the hips in the living patients . Since the twenty-five-year review , three hips were revised ( one because of acetabular loosening , one because of femoral loosening , and one because of instability ) . This end- result study demonstrated the remarkable durability of cemented Charnley total hip replacements over a span of three decades , with 88 % of the original prostheses intact at the time of the final follow-up or at the patient 's death There have been comparatively few studies of the incidence of osteolysis and the survival of hybrid and cementless total hip replacements ( THRs ) in patients younger than 50 years of age . We prospect ively review ed 78 patients ( 109 hips ) with a hybrid THR having a mean age of 43.4 years ( 21 to 50 ) and 79 patients ( 110 hips ) with a cementless THR with a mean age of 46.8 years ( 21 to 49 ) . The patients were evaluated clinical ly using the Harris hip score , the Western Ontario and McMaster Universities ( WOMAC ) osteoarthritis score and the University of California , Los Angeles ( UCLA ) activity score .  Radiographs and CT scans were assessed for loosening and osteolysis . The mean follow-up was for 18.4 years ( 16 to 19 ) in both groups . The mean post-operative Harris hip scores ( 91 points versus 90 points ) , the mean WOMAC scores ( 11 points versus 13 points ) and UCLA activity scores ( 6.9 points versus 7.1 points ) were similar in both groups . The revision rates of the acetabular component ( 13 % versus 16 % ) and the femoral component ( 3 % versus 4 % ) , and the survival of the acetabular component ( 87 % versus 84 % ) and the femoral component ( 97 % versus 96 % ) were similar in both groups . Although the long-term fixation of the acetabular metallic shell and the cemented and cementless femoral components was outst and ing , wear and peri-acetabular osteolysis constitute the major challenges of THR in young patients Hydroxyapatite ( HA ) particles have long been suspected to disintegrate from implant surfaces , become entrapped in joint spaces of orthopaedic bearing couples , and start a cascade leading 
    Output:
    
agent
RESULTS The meta- analysis did not reveal any effect of the type of acetabular component fixation on either survivorship or revision rate .
The preference for cementless acetabular components on the basis of improved survivorship is not supported by the published evidence .
Although concerns regarding aseptic loosening of cemented acetabular components may have led North American surgeons toward the nearly exclusive use of cementless acetabular components , the available literature suggests that the fixation of cemented acetabular components is more reliable than that of cementless components beyond the first postoperative decade
***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: We selected r and omly a consecutive series of 162 patients requiring hip replacement to receive either a cementless , hemispherical , modular , titanium acetabular cup or a cemented , all-polyethylene cup . These replacements were performed by two surgeons in four general hospitals . The same surgical technique was used and a 26 mm metal-head femoral component was used in every case . After exclusions , 115 hips were studied for differences in rates of wear and osteolysis . The mean clinical follow-up was eight years and the mean radiological follow-up , 6.5 years . The cementless cups  wore at a mean rate of 0.15 mm per year and the cemented cups at 0.07 mm per year . This difference was significant ( p < 0.0001 ) . Our findings in this mid-term study suggest that cementless cups  wear more than cemented cups We studied prospect ively the long-term results of the Charnley Elite-Plus femoral stem in 184 consecutive young patients ( 194 hips ) . There were 130 men and 54 women with a mean age of 49.1 years ( 21 to 60 ) . The predominant diagnosis was osteonecrosis of the femoral head ( 63.6 % , 117 patients ) .  Clinical and radiological evaluation was undertaken at each follow-up . The mean follow-up was 11.2 years ( 10 to 12 ) . The mean pre-operative Harris hip score was 43.4 ( 12 to 49 ) which improved to 91 ( 59 to 100 ) at the final follow-up . The survival of the femoral stem  at 12 years was 99 % with revision as the end-point . The mean annual linear wear of the polyethylene liner was 0.17 mm ( 0.13 to 0.22 ) . The prevalence of acetabular osteolysis was 10.8 % ( 21 hips ) and osteolysis of the calcar femorale 12.9 % ( 25 hips ) . A third-generation cementing technique , accurate alignment of the stem and the use of a 22 mm zirconia head were important factors in the prevention of aseptic loosening of the Elite Plus femoral stem in these high-risk young patients Background : We previously reported our two and five‐year results of arthroplasty with the Porous Coated Anatomic total hip prosthesis . We now report on the performance of this prosthesis at ten to fourteen years . Methods : The results of 311 total hip replacements in which a Porous Coated Anatomic prosthesis was inserted without cement in 279 patients were analyzed prospect ively . The average age of the patients at the time of the replacement was sixty-one years ( range , twenty to eighty‐one years ) . Sixty‐four patients ( seventy-six hips ) died postoperatively . Forty‐five patients ( forty‐seven hips ) were lost to follow‐up , and four were excluded because of their medical condition . One hundred and sixty‐eight patients ( 187 hips ) were followed for ten to fourteen years ( average , twelve years ) . Seventeen of those patients ( seventeen hips ) had a revision . Results : The overall survival rate ( with any revision as the end point ) was 90.0 % ± 5.4 % at fourteen years , with an average Harris hip score of 85 ± 14 points . The prevalence of thigh pain was 36 % ( fifty-six of 157 ) in the late period ( more than ten years postoperatively ) . Radiographs showed stable fixation , with bone ingrowth , of 83 % ( 130 ) of the 156 acetabular components and 88 % ( 137 ) of the 156 femoral components at the latest follow‐up evaluation . Men had a significantly higher rate of femoral osteolysis than did women ( p < 0.001 ) . The rates of acetabular and femoral osteolysis associated with 32‐mm femoral heads ( 49 % [ twenty-three ] of forty-seven and 70 % [ thirty-three ] of forty-seven , respectively ) were significantly higher ( p < 0.01 ) than those associated with 26‐mm heads ( 26 % [ twenty-eight ] of 109 and 30 % [ thirty-three ] of 109 , respectively ) . Despite this , revision ( removal or exchange of components ) was not directly related to head size ; instead , it was related to polyethylene thickness . Conclusions : There have been persistent problems with the Porous Coated Anatomic hip system , including thigh pain and an increasing prevalence of osteolysis with time . Revision because of aseptic loosening was related more to the thickness of the polyethylene liner than to the size of the femoral head . Femoral heads with a 32-mm diameter did not increase the risk for revision provided that an adequate thickness of polyethylene had been used Background Even though there are multiple studies documenting the outcome of the Charnley low-friction arthroplasty as well as abundant studies on uncemented arthroplasties , there is a dearth of comparative studies of the uncemented acetabular component and a cemented component . In this study we aim ed to document the long-term clinical and radiographic outcome as well as component survival in a r and omized controlled trial . Material s and methods Two hundred fifteen patients ( 240 hips ) were r and omly allocated to receive a cemented Charnley cup or uncemented Duraloc 1200 cup . All patients received cemented Charnley stems and were evaluated clinical ly and radiographically after 6 months , and 2 , 5 , and 10 years . Results Harris Hip Scores improved from 48.3 [ 95 % confidence interval ( CI ) 45.0–51.6 ] to 90.2 [ 95 % CI 87.9–92.6 ] in the Charnley group and from 49.3 [ 95 % CI 86.9–91.3 ] in the Duraloc group at 6 months . After 10 years , the Charnley group ’s Harris Hip Score was 89.8 [ 95 % confidence interval ( CI ) 87.0–92.6 ] , and the Duraloc group ’s score was 87.3 ( 95 % CI 84.1–90.6 ) . In the radiographic analysis after 10 years , there was no statistical difference in the prevalence of radiographic signs of loosening . Nine cups were revised in the Charnley group , and five cups were removed in the Duraloc group . The difference was not statistically significant . There was no statistical difference between the cups when aseptic loosening was the end-point , nor in survival analyses . Conclusions There is no statistically significant difference in clinical or radiological outcome between the Charnley cup and the Duraloc after 10 years , and no difference in implant survival after 12–14 years . The uncemented Duraloc cup is as good as the cemented Charnley cup after 10 years Abstract : The purpose of this study was to up date the results of a prospect i ve series of primary cementless total hip arthroplasties  after a minimum of fifteen years of follow-up . It is one of the first studies of cementless total hip arthroplasties followed for a minimum of fifteen years . One hundred consecutive Porous Coated Anatomic ( PCA ) total hip replacements were implanted between October 1983 and January 1986 . Fifty-five patients ( sixty-four hips ) that were alive at a minimum of fifteen years postoperatively are the focus of the present study . At this time of follow-up , at an average of 15.6 years ( range , fifteen to seventeen years ) after the total hip arthroplasty , 17 % ( seventeen hips ) of the entire cohort and 23 % ( fifteen hips ) of the living cohort had undergone revision because of loosening of the acetabular component or osteolysis . Seven percent ( seven hips ) of the entire cohort and 6 % ( four hips ) of the living cohort had undergone revision for loosening of the femoral component or osteolysis . Only four femoral stems had been revised for isolated loosening ( without osteolysis).The  PCA femoral component proved to be durable at a minimum of fifteen years postoperatively , while the acetabular component was less durable . Level of Evidence : Therapeutic study , Level IV ( case series [ no , or historical , control group ] ) . See Instructions to Authors for a complete description of levels of evidence We enrolled 98 patients ( 107 hips ) with a mean age of 47 years ( SD 8.6 ) into a prospect i ve study of the Madreporic Lord THR ; 34 hips had primary and 73 secondary osteoarthritis . After ten years , the survival rate using revision as the endpoint for failure was 70 % ( + /-9 ) for the cup and 98 % ( + /-0.3 ) for the stem . The combined clinical and radiological survival rates were 46 % ( + /-11 ) and 81 % ( + /-10 ) , respectively . Osteoporosis due to stress-shielding was observed in the proximal femur . Hips with radiologically dense bone postoperatively showed the most pronounced bone loss . We recommend continued radiological follow-up of patients with this type of implant to allow revision to be performed before there is severe bony destruction of the pelvis In a prospect i ve study , 93 unselected consecutive uncemented hip arthroplasties were performed in 80 patients using the  titanium-coated RM acetabular component and the CLS femoral component .  The mean age of the patients at operation was 52 years ( 28 to 81 ) . None were lost to follow-up . In the 23 patients who had died ( 26 hips ) only one acetabular component had been revised . In the 57 living patients ( 67 hips ) , 13 such revisions had been performed . Of the 14 revisions , seven were for osteolysis , five for loosening and two for infection . Survival analysis of this implant showed a total probability of survival of 83 % ( 95 % confidence interval 73 to 90 ) , with all revisions as the endpoint , and a probability of 94 % ( 95 % confidence interval 87 to 98 ) with revision for aseptic loosening as the endpoint , indicating reliable long-term fixation of the titanium-coated RM acetabular component The purpose of the current study was to up date the results of a prospect i ve , single-surgeon series of primary Charnley total hip arthroplasties performed with cement . This investigation is one of the first studies in which hips treated with total hip arthroplasty with cement  were followed for a minimum of thirty years . Twenty-seven patients ( thirty-four [ 10.3 % ] of the hips in the initial study group ) were alive at a minimum of thirty years postoperatively . These patients served as the focus of the present study .  Revision because of aseptic loosening of the acetabular component was performed in 7.3 % ( twenty-three ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 26 % ( eight ) of the hips in the living cohort .  Revision  because of aseptic loosening of the femoral component was performed in 3.2 % ( ten ) of the hips from the original study group ( excluding those revised because of infection or dislocation ) and 10 % ( three ) of the hips in the living patients . Since the twenty-five-year review , three hips were revised ( one because of acetabular loosening , one because of femoral loosening , and one because of instability ) . This end- result study demonstrated the remarkable durability of cemented Charnley total hip replacements over a span of three decades , with 88 % of the original prostheses intact at the time of the final follow-up or at the patient 's death There have been comparatively few studies of the incidence of osteolysis and the survival of hybrid and cementless total hip replacements ( THRs ) in patients younger than 50 years of age . We prospect ively review ed 78 patients ( 109 hips ) with a hybrid THR having a mean age of 43.4 years ( 21 to 50 ) and 79 patients ( 110 hips ) with a cementless THR with a mean age of 46.8 years ( 21 to 49 ) . The patients were evaluated clinical ly using the Harris hip score , the Western Ontario and McMaster Universities ( WOMAC ) osteoarthritis score and the University of California , Los Angeles ( UCLA ) activity score .  Radiographs and CT scans were assessed for loosening and osteolysis . The mean follow-up was for 18.4 years ( 16 to 19 ) in both groups . The mean post-operative Harris hip scores ( 91 points versus 90 points ) , the mean WOMAC scores ( 11 points versus 13 points ) and UCLA activity scores ( 6.9 points versus 7.1 points ) were similar in both groups . The revision rates of the acetabular component ( 13 % versus 16 % ) and the femoral component ( 3 % versus 4 % ) , and the survival of the acetabular component ( 87 % versus 84 % ) and the femoral component ( 97 % versus 96 % ) were similar in both groups . Although the long-term fixation of the acetabular metallic shell and the cemented and cementless femoral components was outst and ing , wear and peri-acetabular osteolysis constitute the major challenges of THR in young patients Hydroxyapatite ( HA ) particles have long been suspected to disintegrate from implant surfaces , become entrapped in joint spaces of orthopaedic bearing couples , and start a cascade leading 
    Output:
    