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: The first 100 consecutive primary hip arthroplasties with the Arthopor 2 acetabular component ( Joint Medical Products , Stamford , CT ) with supplemental screw fixation performed by the senior author were prospect ively studied . The mean patient age was 57 years . Seventy-seven cemented and 23 cementless stems were placed , with 32-mm femoral heads used in most of the patients . Eighty-six hips were review ed at 7 - 8.8 years ( mean , 7.8 years ) . The mean Harris hip score at final follow-up evaluation was 94 points . No cups have been revised , although 2 cups in patients with radiation osteonecrosis were loose radiographically . One patient underwent revision of a severely worn liner . Despite a relatively high mean linear wear rate of 0.27 mm/y ( range , 0.13 - 0.57 mm/y ) , no radiographic evidence of pelvic osteolysis was seen . The Arthopor 2 cup performed well with respect to pelvic osteolysis , despite the presence of substantial polyethylene debris . The relatively high polyethylene wear rate is attributed in part to the younger patient population and the use of 32-mm femoral heads paired with thin polyethylene liners The purpose of this study was to evaluate the clinical outcomes and possible causes of early failure in a multicenter trial of metal-on-metal hip resurfacing . Two hundred patients were prospect ively enrolled and followed for an average of 31.2 months ( range , 12 - 54 months ) . Of 200 patients , 14 ( 7.0 % ) required revision surgery at a mean time of 19.5 months ( range , 3 - 47 months ) . Patients with failures were significantly younger and heavier than the nonfailures , and all were male . Patients who were revised did not differ from those who were not revised in terms of radiographic outcomes , but they did report lower functional outcome scores at all preoperative and postoperative testing intervals . Most failures ( 10/14 ) were related to early acetabular loosening . The learning curve was likely a factor in these cup failures . This report highlights the importance of patient selection and surgical technique in hip resurfacing arthroplasty . It is anticipated that further surgical experience will lead to a reduction in this high early failure rate We describe the experience with the first consecutive 230 Birmingham hip resurfacings at our centre . At a mean follow-up of three years ( 25 to 52 months ) survivorship was 99.14 % with revision in one patient for a loose acetabular component and one death from unrelated causes . One patient developed a fracture of the femoral neck at six weeks which united unremarkably after a period of non-weight-bearing . The Harris hip score improved from a mean of 62.54 ( 8 to 92 ) to 97.74 ( 61 to 100 ) . The mean flexion improved from 91.52 degrees ( 25 to 140 ) to 110.41 degrees ( 80 to 145 ) . Most patients ( 97 % ) considered the outcome to be good or excellent . Our preliminary experience with this implant is encouraging and the results are superior to the earlier generation of resurfacings for the same length of follow-up A comparison of pertinent preoperative and postoperative data relative to total hip resurfacing versus total hip arthroplasty ( THA ) would assist in evaluating current perceptions in outcome . We compared 50 consecutive metal-metal resurfacing replacements in 50 patients with 44 consecutive conventional total hip arthroplasties in 35 patients , who were implanted during the same time period , by the same surgeon , and followed prospect ively for 2 to 4 years . The patients undergoing hip resurfacing were 62 % male , 9 years younger , and 3.2 inches taller , with a lower mean body mass index and American Society of Anesthesiologists ( ASA ) grade than patients undergoing total hip arthroplasty .  Preoperatively , patients undergoing resurfacing had a lower Harris hip score ( 46 vs 52 points ) , more pain , higher UCLA ( University of California at Los Angeles ) activity scores ( 4.2 vs 3.6 ) , and better range of motion . Surgical time for resurfacing was 18 % longer , but there was less total blood loss and fewer transfusions . Postoperatively , there was no difference in Harris hip score ( 97 vs 96 ) . Patients undergoing resurfacing had higher function , Short Form-12 physical activity scores , and UCLA activity scores , but also a higher incidence of slight or mild pain . There were no differences in postoperative range of motion or dislocation ( one each ) . The preoperative characteristics and general health status of the average patient undergoing resurfacing are more favorable than that of the average patient undergoing conventional total hip arthroplasty . Caution should be applied in attributing differences in outcomes directly to the arthroplasty technology Background To investigate prospect ively the patient-relevant outcome 7 years after  total hip replacement ( THR ) for osteoarthritis ( OA ) . Methods 219 consecutive patients ( 120 women ) with primary OA , mean age 71 ( range 50 - 92 ) were assigned for THR .  They were examined preoperatively , at 3 , 6 , 12 months , and at 4 , 5 and 7 years postoperatively with the self-administered question naires SF-36 and WOMAC . Supplementary questions regarding postoperative complications , general co-morbidity , social circumstances and patient satisfaction were asked at the three last follow-ups . A reference group , 117 subjects ( 67 women ) , mean age 72 ( range 52 - 92 ) without hip complaints were recruited from the community and investigated at the same times . Results 151/170 ( 89 % ) of the patients and 65/74 ( 88 % ) of the reference group participated at the 7 year follow-up . The best postoperative result was reported one year postoperatively . At the 7 year follow up there was a significant difference between the patients and controls in SF-36 physical function ( PF ) and role physical ( RP ) but not of WOMAC function . There was no difference in frequency of co-morbid conditions between those operated and the reference group , but those operated were in greater need of walking aid ( 46 % vs. 8 % p < 0.0001 ) and reported more regional and widespread pain ( 68 % vs. 53 % p < 0.05 ) . Conclusion This study shows that in an unselected cohort the patients experience a similar health-related quality of life as a reference group of a similar age and sex structure 7 years after THR except for general physical function where the patients score worse OBJECTIVE To evaluate the effect of obesity on the incidence of main complications ( infection , dislocation , and revision ) , functional outcome , and patient satisfaction 5 years after primary total hip arthroplasty ( THA )  , and to determine whether results differ between obese women and men . METHODS We conducted a hospital-based prospect i ve cohort study including patients who underwent primary THA ( 2,495 hips ) between 1996 and 2005 . We used rates and rate ratios to compare the incidence of main complications in obese and nonobese patients , and we stratified the data for sex . Functional outcome was measured using the Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index . RESULTS The adjusted incidence rate ratio for infection ( obese versus nonobese ) was 4.4 ( 95 % confidence interval [ 95 % CI ] 1.8 , 10.8 ) . Obesity substantially increased the infection rate in women ( incidence rate ratio comparing obese with nonobese women 16.1 ; 95 % CI 3.4 , 75.7 ) , whereas obesity appeared to have no effect in men ( incidence rate ratio 1.0 ; 95 % CI 0.2 , 5.3 ) . The adjusted incidence rate ratio for dislocation ( obese versus nonobese ) was 2.4 ( 95 % CI 1.4 , 4.2 ) , with a higher rate increase in obese women . A total of 817 patients had a 5-year clinical followup visit . Functional outcome and satisfaction were slightly lower in obese women partly due to higher complication rates . No difference was seen in men . CONCLUSION Primary THA is a successful intervention in obese patients , but physician and patient must be aware of increased complications , particularly in women We report an independent prospect i ve review of the first 230 Birmingham hip resurfacings in 212 patients at a mean follow-up of five years ( 4 to 6 ) . Two patients , one with a loose acetabular component and the other with suspected avascular necrosis of the femoral head , underwent revision . There were two deaths from unrelated causes and one patient was lost to follow-up . The survivorship with the worst-case scenario was 97.8 % ( 95 % confidence interval 95.8 to 99.5 ) . The mean Harris hip score improved significantly ( paired t-test , p < 0.05 ) from 62.54 ( 8 to 92 ) pre-operatively to 97.7 ( 61 to 100 ) at a mean of three years ( 2.1 to 4.3 ) , then deteriorated slightly to a mean of 95.2 ( 47 to 100 ) at a mean of five years . The mean flexion improved from 91.5 degrees ( 25 degrees to 140 degrees ) to 110.4 degrees ( 80 degrees to 145 degrees ) at a mean of three years with no further improvement at five years ( 111.2 degrees ; 70 degrees to 160 degrees ) . On radiological review at five years , one patient had a progressive lucent line around the acetabular component and six had progressive lucent lines around the femoral component . A total of 18 femoral components ( 8 % ) had migrated into varus and those with lucent lines present migrated a mean of 3.8 degrees ( 1.02 degrees to 6.54 degrees ) more than the rest . Superolateral notching of the femoral neck and reactive sclerosis at the tip of the peg of the femoral component were associated with the presence of lucent lines ( chi-squared test , p < 0.05 ) , but not with migration of the femoral component , and are of unknown significance . Our results with the Birmingham hip resurfacing continue to be satisfactory at a mean follow-up of five years Objectives : To investigate prospect ively long term patient relevant outcomes after  unilateral total hip replacement ( THR ) for osteoarthritis ( OA ) . To identify non-responders to this intervention and patient related predictors of unsatisfactory outcome . Methods : A case-control study comparing health related quality of life of 219 patients ( mean age 71 ) after THR with that of a matched reference group of 117 subjects without hip complaints recruited from the community . Patients and reference group answered SF-36 and WOMAC question naires preoperatively , at 3 , 6 , 12 months , and at 3.6 years ( range 26–65 months ) postoperatively . Supplementary questions were asked at the final follow up . Results : 198/211 ( 94 % ) of the patients and 83/109 ( 76 % ) of the reference group participated at the final follow up . At follow up , the only difference between the two groups in the SF-36 was physical function , where patients scored worse . Patients also reported worse WOMAC function . 31 % of the patients had improved by < 10/100 WOMAC score points for pain and /or function at final follow up , compared with preoperatively . More pain preoperatively and higher age and postoperative low back pain predicted a worse outcome in WOMAC function . Conclusion : 3.6 years after THR for OA , health related quality of life was similar for patients and reference group except for function , where patients had worse function . Higher age and more pain preoperatively predicted a poor outcome . Patients with hip OA with musculoskeletal comorbidities , such as low back pain and OA of the non-operated hip , have less long term functional improvement after THR Objective To investigate differences in pre- and postoperative patient-relevant outcome between hybrid total hip replacement ( THR ) and cemented THR in patients with primary osteoarthritis ( OA ) . Methods 245 consecutive patients were included in the study . 68 of the patients ( mean age 62 ) were operated on with hybrid THR and 177 ( mean age 74 ) were operated on with cemented THR .  All patients were investigated preoperatively and 0.5 , 1 and 3.6 years postoperatively with two self-administered question naires , SF-36 and WOMAC ( Western Ontario and MacMaster Universities Osteoarthritis Index , LK 3.0 ) . Results Preoperatively , there was a difference in the SF-36 subscales RP ( role physical ) and GH ( general health ) where the patients with the hybrid THR attained better scores . At 3.6-years the patients with the hybrid THR reached better scores in all SF-36 subscales except BP ( bodily pain ) and GH . Further , they had better scores in WOMAC function . However , after adjusting for age , sex , follow-up time and baseline values there were no differences in outcome between the two different surgical techniques . Conclusion This medium term ( 3–5 years ) , controlled , open cohort study , using patient-relevant outcome measures , did not reveal any differences between hybrid THR and cemented THR for OA at 3.6 years after surgery . Since the study had 75–94 % power to detect the clinical ly significant score difference of 10 points , we suggest that any difference in outcome between these two methods is small and may require a large-scale , blinded , r and om 
    Output:
    
agent
Conclusions Revisions and reoperations are more frequent and occur earlier with metal-on-metal hip resurfacing , except when discontinued devices are removed from the analyses .
***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: The first 100 consecutive primary hip arthroplasties with the Arthopor 2 acetabular component ( Joint Medical Products , Stamford , CT ) with supplemental screw fixation performed by the senior author were prospect ively studied . The mean patient age was 57 years . Seventy-seven cemented and 23 cementless stems were placed , with 32-mm femoral heads used in most of the patients . Eighty-six hips were review ed at 7 - 8.8 years ( mean , 7.8 years ) . The mean Harris hip score at final follow-up evaluation was 94 points . No cups have been revised , although 2 cups in patients with radiation osteonecrosis were loose radiographically . One patient underwent revision of a severely worn liner . Despite a relatively high mean linear wear rate of 0.27 mm/y ( range , 0.13 - 0.57 mm/y ) , no radiographic evidence of pelvic osteolysis was seen . The Arthopor 2 cup performed well with respect to pelvic osteolysis , despite the presence of substantial polyethylene debris . The relatively high polyethylene wear rate is attributed in part to the younger patient population and the use of 32-mm femoral heads paired with thin polyethylene liners The purpose of this study was to evaluate the clinical outcomes and possible causes of early failure in a multicenter trial of metal-on-metal hip resurfacing . Two hundred patients were prospect ively enrolled and followed for an average of 31.2 months ( range , 12 - 54 months ) . Of 200 patients , 14 ( 7.0 % ) required revision surgery at a mean time of 19.5 months ( range , 3 - 47 months ) . Patients with failures were significantly younger and heavier than the nonfailures , and all were male . Patients who were revised did not differ from those who were not revised in terms of radiographic outcomes , but they did report lower functional outcome scores at all preoperative and postoperative testing intervals . Most failures ( 10/14 ) were related to early acetabular loosening . The learning curve was likely a factor in these cup failures . This report highlights the importance of patient selection and surgical technique in hip resurfacing arthroplasty . It is anticipated that further surgical experience will lead to a reduction in this high early failure rate We describe the experience with the first consecutive 230 Birmingham hip resurfacings at our centre . At a mean follow-up of three years ( 25 to 52 months ) survivorship was 99.14 % with revision in one patient for a loose acetabular component and one death from unrelated causes . One patient developed a fracture of the femoral neck at six weeks which united unremarkably after a period of non-weight-bearing . The Harris hip score improved from a mean of 62.54 ( 8 to 92 ) to 97.74 ( 61 to 100 ) . The mean flexion improved from 91.52 degrees ( 25 to 140 ) to 110.41 degrees ( 80 to 145 ) . Most patients ( 97 % ) considered the outcome to be good or excellent . Our preliminary experience with this implant is encouraging and the results are superior to the earlier generation of resurfacings for the same length of follow-up A comparison of pertinent preoperative and postoperative data relative to total hip resurfacing versus total hip arthroplasty ( THA ) would assist in evaluating current perceptions in outcome . We compared 50 consecutive metal-metal resurfacing replacements in 50 patients with 44 consecutive conventional total hip arthroplasties in 35 patients , who were implanted during the same time period , by the same surgeon , and followed prospect ively for 2 to 4 years . The patients undergoing hip resurfacing were 62 % male , 9 years younger , and 3.2 inches taller , with a lower mean body mass index and American Society of Anesthesiologists ( ASA ) grade than patients undergoing total hip arthroplasty .  Preoperatively , patients undergoing resurfacing had a lower Harris hip score ( 46 vs 52 points ) , more pain , higher UCLA ( University of California at Los Angeles ) activity scores ( 4.2 vs 3.6 ) , and better range of motion . Surgical time for resurfacing was 18 % longer , but there was less total blood loss and fewer transfusions . Postoperatively , there was no difference in Harris hip score ( 97 vs 96 ) . Patients undergoing resurfacing had higher function , Short Form-12 physical activity scores , and UCLA activity scores , but also a higher incidence of slight or mild pain . There were no differences in postoperative range of motion or dislocation ( one each ) . The preoperative characteristics and general health status of the average patient undergoing resurfacing are more favorable than that of the average patient undergoing conventional total hip arthroplasty . Caution should be applied in attributing differences in outcomes directly to the arthroplasty technology Background To investigate prospect ively the patient-relevant outcome 7 years after  total hip replacement ( THR ) for osteoarthritis ( OA ) . Methods 219 consecutive patients ( 120 women ) with primary OA , mean age 71 ( range 50 - 92 ) were assigned for THR .  They were examined preoperatively , at 3 , 6 , 12 months , and at 4 , 5 and 7 years postoperatively with the self-administered question naires SF-36 and WOMAC . Supplementary questions regarding postoperative complications , general co-morbidity , social circumstances and patient satisfaction were asked at the three last follow-ups . A reference group , 117 subjects ( 67 women ) , mean age 72 ( range 52 - 92 ) without hip complaints were recruited from the community and investigated at the same times . Results 151/170 ( 89 % ) of the patients and 65/74 ( 88 % ) of the reference group participated at the 7 year follow-up . The best postoperative result was reported one year postoperatively . At the 7 year follow up there was a significant difference between the patients and controls in SF-36 physical function ( PF ) and role physical ( RP ) but not of WOMAC function . There was no difference in frequency of co-morbid conditions between those operated and the reference group , but those operated were in greater need of walking aid ( 46 % vs. 8 % p < 0.0001 ) and reported more regional and widespread pain ( 68 % vs. 53 % p < 0.05 ) . Conclusion This study shows that in an unselected cohort the patients experience a similar health-related quality of life as a reference group of a similar age and sex structure 7 years after THR except for general physical function where the patients score worse OBJECTIVE To evaluate the effect of obesity on the incidence of main complications ( infection , dislocation , and revision ) , functional outcome , and patient satisfaction 5 years after primary total hip arthroplasty ( THA )  , and to determine whether results differ between obese women and men . METHODS We conducted a hospital-based prospect i ve cohort study including patients who underwent primary THA ( 2,495 hips ) between 1996 and 2005 . We used rates and rate ratios to compare the incidence of main complications in obese and nonobese patients , and we stratified the data for sex . Functional outcome was measured using the Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index . RESULTS The adjusted incidence rate ratio for infection ( obese versus nonobese ) was 4.4 ( 95 % confidence interval [ 95 % CI ] 1.8 , 10.8 ) . Obesity substantially increased the infection rate in women ( incidence rate ratio comparing obese with nonobese women 16.1 ; 95 % CI 3.4 , 75.7 ) , whereas obesity appeared to have no effect in men ( incidence rate ratio 1.0 ; 95 % CI 0.2 , 5.3 ) . The adjusted incidence rate ratio for dislocation ( obese versus nonobese ) was 2.4 ( 95 % CI 1.4 , 4.2 ) , with a higher rate increase in obese women . A total of 817 patients had a 5-year clinical followup visit . Functional outcome and satisfaction were slightly lower in obese women partly due to higher complication rates . No difference was seen in men . CONCLUSION Primary THA is a successful intervention in obese patients , but physician and patient must be aware of increased complications , particularly in women We report an independent prospect i ve review of the first 230 Birmingham hip resurfacings in 212 patients at a mean follow-up of five years ( 4 to 6 ) . Two patients , one with a loose acetabular component and the other with suspected avascular necrosis of the femoral head , underwent revision . There were two deaths from unrelated causes and one patient was lost to follow-up . The survivorship with the worst-case scenario was 97.8 % ( 95 % confidence interval 95.8 to 99.5 ) . The mean Harris hip score improved significantly ( paired t-test , p < 0.05 ) from 62.54 ( 8 to 92 ) pre-operatively to 97.7 ( 61 to 100 ) at a mean of three years ( 2.1 to 4.3 ) , then deteriorated slightly to a mean of 95.2 ( 47 to 100 ) at a mean of five years . The mean flexion improved from 91.5 degrees ( 25 degrees to 140 degrees ) to 110.4 degrees ( 80 degrees to 145 degrees ) at a mean of three years with no further improvement at five years ( 111.2 degrees ; 70 degrees to 160 degrees ) . On radiological review at five years , one patient had a progressive lucent line around the acetabular component and six had progressive lucent lines around the femoral component . A total of 18 femoral components ( 8 % ) had migrated into varus and those with lucent lines present migrated a mean of 3.8 degrees ( 1.02 degrees to 6.54 degrees ) more than the rest . Superolateral notching of the femoral neck and reactive sclerosis at the tip of the peg of the femoral component were associated with the presence of lucent lines ( chi-squared test , p < 0.05 ) , but not with migration of the femoral component , and are of unknown significance . Our results with the Birmingham hip resurfacing continue to be satisfactory at a mean follow-up of five years Objectives : To investigate prospect ively long term patient relevant outcomes after  unilateral total hip replacement ( THR ) for osteoarthritis ( OA ) . To identify non-responders to this intervention and patient related predictors of unsatisfactory outcome . Methods : A case-control study comparing health related quality of life of 219 patients ( mean age 71 ) after THR with that of a matched reference group of 117 subjects without hip complaints recruited from the community . Patients and reference group answered SF-36 and WOMAC question naires preoperatively , at 3 , 6 , 12 months , and at 3.6 years ( range 26–65 months ) postoperatively . Supplementary questions were asked at the final follow up . Results : 198/211 ( 94 % ) of the patients and 83/109 ( 76 % ) of the reference group participated at the final follow up . At follow up , the only difference between the two groups in the SF-36 was physical function , where patients scored worse . Patients also reported worse WOMAC function . 31 % of the patients had improved by < 10/100 WOMAC score points for pain and /or function at final follow up , compared with preoperatively . More pain preoperatively and higher age and postoperative low back pain predicted a worse outcome in WOMAC function . Conclusion : 3.6 years after THR for OA , health related quality of life was similar for patients and reference group except for function , where patients had worse function . Higher age and more pain preoperatively predicted a poor outcome . Patients with hip OA with musculoskeletal comorbidities , such as low back pain and OA of the non-operated hip , have less long term functional improvement after THR Objective To investigate differences in pre- and postoperative patient-relevant outcome between hybrid total hip replacement ( THR ) and cemented THR in patients with primary osteoarthritis ( OA ) . Methods 245 consecutive patients were included in the study . 68 of the patients ( mean age 62 ) were operated on with hybrid THR and 177 ( mean age 74 ) were operated on with cemented THR .  All patients were investigated preoperatively and 0.5 , 1 and 3.6 years postoperatively with two self-administered question naires , SF-36 and WOMAC ( Western Ontario and MacMaster Universities Osteoarthritis Index , LK 3.0 ) . Results Preoperatively , there was a difference in the SF-36 subscales RP ( role physical ) and GH ( general health ) where the patients with the hybrid THR attained better scores . At 3.6-years the patients with the hybrid THR reached better scores in all SF-36 subscales except BP ( bodily pain ) and GH . Further , they had better scores in WOMAC function . However , after adjusting for age , sex , follow-up time and baseline values there were no differences in outcome between the two different surgical techniques . Conclusion This medium term ( 3–5 years ) , controlled , open cohort study , using patient-relevant outcome measures , did not reveal any differences between hybrid THR and cemented THR for OA at 3.6 years after surgery . Since the study had 75–94 % power to detect the clinical ly significant score difference of 10 points , we suggest that any difference in outcome between these two methods is small and may require a large-scale , blinded , r and om 
    Output:
    