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 For total hip arthroplasty ( THA ) , minimally invasive surgery ( MIS ) uses a smaller incision and less muscle dissection than the classic approach ( CLASS ) , and may lead to faster rehabilitation . Questions / purpose sDoes minimally invasive hip arthroplasty result in superior clinical outcomes ? Patients and Methods In this double-blind r and omized controlled trial , 120 consecutive primary noncemented THAs in 120 patients were assigned to one of two groups ( MIS or CLASS ) . The r and omization sequence was stratified for two groups of surgeons , ie , those using a posterolateral approach ( PL-CLASS or PL-MIS ) and those using an anterolateral approach ( AL-CLASS or AL-MIS ) . Length of the incisions was 18 cm for the CLASS procedures . MIS incisions were extended at the skin level to 18 cm at the end of the procedure . The primary end point was the Harris hip score ( HHS ) at 6 weeks postoperatively . Patient-centered question naires were obtained preoperatively and after 6 weeks and 1 year . Results For the patients in the MIS group ( average 7.8 cm incision length ) , statistically significant increased mean HHSs were seen compared with the CLASS group at 6 weeks and 1 year . This difference was small and mainly caused by the favorable results of the PL-MIS . In the MIS group , surgical time was longer . A learning curve was observed based on operation time and complication rate . Although not statistically significant , the perioperative complication rate was rather high in the ( anterolateral ) MIS group . Conclusions The minimal invasive approach in THA did not show a clinical ly relevant superior outcome in the first postoperative year . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence Introduction Minimally invasive total hip arthroplasty ( THA ) is cl aim ed to be superior to the st and ard technique , due to the potential reduction of soft tissue damage via a smaller and tissue-sparing approach . As a result of the lack of objective evidence of fewer muscle and tendon defects , controversy still remains as to whether minimally invasive total hip arthroplasty truly minimizes muscle and tendon damage . Therefore , the objective was to compare the influence of the surgical approach on abductor muscle trauma and to analyze the relevance to postoperative pain and functional recovery . Material s and methods Between June 2006 and July 2007 , 44 patients with primary hip arthritis were prospect ively included in the study protocol . Patients underwent cementless unilateral total hip arthroplasty either through a minimally invasive anterolateral approach ( ALMI ) ( n = 21 ) or a modified direct lateral approach ( mDL ) ( n = 16 ) . Patients were evaluated clinical ly and underwent MR imaging preoperatively and at 3 and 12 months postoperatively . Clinical assessment contained clinical examination , performance of abduction test and the survey of a function score using the Harris Hip Score , a pain score using a numeric rating scale ( NRS ) of 0–10 , as well as a satisfaction score using an NRS of 1–6 . Additionally , myoglobin and creatine kinase were measured preoperatively , and 6 , 24 and 96 h postoperatively . Evaluation of the MRI images included fatty atrophy ( rating scale 0–4 ) , tendon defects ( present/absent ) and bursal fluid collection of the abductor muscle . Results Muscle and tendon damage occurred in both groups , but more lateral gluteus medius tendon defects [ mDL 3/12mth . : 6 (37%)/4 ( 25 % ) ; ALMI : 3 (14%)/2 ( 9 % ) ] and muscle atrophy in the anterior part of the gluteus medius [ mean-st and ard ( 12 ) : 1.75 ± 1.8 ; mean-MIS ( 12 ) : 0.98 ± 1.1 ] were found in patients with the mDL approach . The clinical outcome was also poorer compared to the ALMI group . Significantly , more Trendelenburg ’s signs were evident and lower clinical scores were achieved in the mDL group . No differences in muscle and tendon damage were found for the gluteus minimus muscle . A higher serum myoglobin concentration was measured 6 and 24 h postoperatively in the mDL group ( 6 h : 403 ± 168 μg/l ; 24 h : 304 ± 182 μg/l ) compared to the ALMI group ( 6 h : 331 ± 143 μg/l ; 24 h : 268 ± 145 μg/l ) . Conclusion Abductor muscle and tendon damage occurred in both approaches , but the gluteus medius muscle can be spared more successfully via the minimally invasive approach and is accompanied by a better clinical outcome . Therefore , going through the intermuscular plane , without any detachment or dissection of muscle and tendons , truly minimizes perioperative soft tissue trauma . Furthermore , MRI emerges as an important imaging modality in the evaluation of muscle trauma in THA Benefits of a direct anterior approach ( DAA ) versus a posterior-lateral ( PA ) approach to THA were assessed in a single-surgeon , IRB-approved , prospect i ve , r and omized clinical study . Subjects ( 43 DAA and 44 PA ) were evaluated at 6 weeks , and 3 , 6 and 12 months . The primary end point was ability to climb stairs normally and walk unlimited at each time point . Secondary end points included assessment by several outcome instruments . DAA subjects performed better during the immediate post-operative period ; they had lower VAS pain scores on the first post-operative day , more subjects climbing stairs normally and walking unlimited at 6 weeks , and higher HOOS Symptoms scores at 3 months . There were no significant differences between groups at later time points . Findings confirm previous reports of benefits of DAA versus PA in early post-operative phases The purpose s of this study were to determine the impact of surgical approach on costs of  total hip arthroplasty ( THA )  from a hospital perspective and to provide an up date d cost estimation of THA . A prospect i ve , microcosting analysis was performed on 118 patients undergoing a THA through an anterior , lateral , or posterior approach .  We determined that overall costs ( intraoperative costs and hospital stay ) were significantly less for the anterior ( $ 7300.22 ; 95 % confidence interval [ CI ] , 7064.49 - 7535.95 ) vs lateral ( $ 7853.10 ; 95 % CI , 7577.29 - 8128.91 ; P = .031 ) and anterior vs posterior approach ( $ 8287.46 ; 95 % CI , 7906.42 - 8668.51 ; P < .001 ) . A reduction in hospital length of stay when THA was performed through an anterior approach contributed significantly to an overall reduction in costs from a hospital perspective Objective The aim of the present study was to identify independent preoperative hip function characteristics sensitive for preoperative intervention that are predictive of an extended length of hospital stay ( LOS ) after primary total hip arthroplasty ( THA ) .  Design This is a longitudinal cohort study . A retrospective chart analysis was conducted on prospect ively collected data of patients ( 158 ) who underwent unilateral primary elective cemented THA in a 4-yr period . The main outcome measure was LOS after primary THA . Results The median LOS was 6.0 days . The authors found an 18.5 % increased chance of requiring an LOS of more than 6 days ( odds ratio , 2.15 ; 95 % confidence interval , 1.03–4.50 ) for the patients who needed to use a walking aid preoperatively and a 23.6 % increased chance ( odds ratio , 2.74 ; 95 % confidence interval , 1.31–5.74 ) for the patients who had difficulties managing stairs . Sex , age , body mass index , comorbidity , and preoperative pain did not reach the level of significance in the multivariate analysis . Conclusions Patients who are at risk for a longer stay in the hospital after THA can be identified preoperatively on simple physical function characteristics . These findings enable the identification of appropriate patients for preoperative training to improve functional recovery and decrease the LOS after primary THA Introduction We conducted a prospect i ve study to compare the exposure and implant positioning in primary total hip replacement through the anterolateral minimally invasive ( ALMI ) approach versus the posterior minimally invasive ( PMI ) approach . Material s and methods We applied these techniques to 2 consecutive groups ( 33 and 43 patients , respectively ) comparable preoperatively . All the patients received the same cementless stem and acetabular component . Results There were neither significant difference in femoral or acetabular component positioning nor in limb-length discrepancy . Acetabular exposure was easy through the ALMI approach . Femoral exposure was more difficult as fractures of the trochanter and femoral perforation in our study show . Conclusion For us , exposure and implant positioning through the ALMI approach and the PMI approach are comparable and reliable . However , we recommend caution during the initial learning curve in osteoporotic patients due to the higher rate of peroperative complications for the ALMI approach Background and purpose — Criticism of the lateral approach ( LA ) for hip arthroplasty is mainly based on the risk of poor patient-reported outcomes compared to the posterior approach ( PA ) . However , there have been no controlled studies comparing patient-reported outcomes between them . In this r and omized controlled trial , we tested the hypothesis that patient-reported outcomes are better in patients who have undergone total hip arthroplasty ( THA ) with PA  than in those who have undergone THA with LA , 12 months postoperatively . Patients and methods — 80 patients with hip osteoarthritis ( mean age 61 years ) were r and omized to THA  using  PA or the modified direct LA . We recorded outcome measures preoperatively and 3 , 6 , and 12 months postoperatively using the Hip Disability and Osteoarthritis Outcome Score – Physical Function Short Form ( HOOS-PS ) as the primary outcome . Secondary outcomes were HOOS-Pain , HOOS- Quality -Of-Life , EQ-5D , UCLA Activity Score , and limping . Results — We found no statistically significant difference in the improvements in HOOS-PS between the treatment groups at 12-month follow-up . All secondary outcomes showed similar results except for limping , where PA patients improved significantly more than LA patients . Interpretation — Contrary to our hypothesis , patients treated with PA did not improve more than patients treated with LA regarding physical function , pain , physical activity , and quality of life 12 months postoperatively . However , limping was more pronounced in the LA patients BACKGROUND Minimally invasive total hip arthroplasty has stirred substantial controversy with regard to whether it provides superior outcomes compared with total hip arthroplasty performed through longer incisions . The orthopaedic literature is deficient in well- design ed scientific studies to support the clinical superiority of this approach . The objective of this study was to compare the results of a single mini-incision approach with those of a st and ard-incision total hip arthroplasty in the early postoperative period . METHODS Two hundred and nineteen patients ( 219 hips ) admitted for unilateral total hip arthroplasty between December 2003 and June 2004 were r and omized to undergo surgery through a short incision of < or=10 cm or a st and ard incision of 16 cm .  All patients were blinded to the size of the incision for the duration of the hospital stay . The anesthetic , analgesic , and postoperative physiotherapy protocol s were st and ardized , with the staff also blinded to the technique used . A single surgeon , who had performed more than 300 short-incision hip replacements prior to the start of this study and who performs an average of 415 primary total hip replacements a year , performed all procedures through a single-incision posterior approach using a cementless cup and cemented stem . RESULTS The two groups were matched for age , grade according to the system of the American Society of Anesthesiologists , and body mass index . No significant difference was detected with respect to postoperative hematocrit , blood transfusion requirements , pain scores , or analgesic use . We found no difference in early walking ability or length of hospital stay and no difference in component placement , cement-mantle quality , or functional outcome scores at six weeks . The patient variables significantly associated with a probability of early discharge independent of incision length were patient age and preoperative hemoglobin levels ( p < 0.05 ) . The surgical scars contracted significantly over six weeks ( p < 0.05 ) but by a similar proportion of 11 % to 12 % in both groups . CONCLUSIONS Minimally invasive total hip arthroplasty performed through a single-incision posterior approach by a high-volume hip surgeon with extensive experience in less invasive approaches to the hip is safe and reproducible . However , it offers no significant benefit in the early postoperative period compared with a st and ard incision of 16 cm . As it is not known whether lower-volume and less-experienced surgeons can achieve similar results , the mini-incision technique merits further study before wide dissemination and implementation of this family of surgical approaches can be recommended Purpose The purpose of this study was to evaluate pre-operative education versus no education and mini-invasive surgery versus st and ard surgery to reach complete independence . Methods We conducted a four-arm r and omized controlled trial of 209 patients . The primary outcome criterion was the time to reach complete functional independence . Secondary outcomes included the operative time , the estimated total blood loss , the pain level , the dose of morphine , and the time to discharge . Results There was no significant effect of either education ( HR :  
    Output:
    
agent
The posterolateral approach reported the lowest value for the surgical duration .
The posterolateral approach reported the shortest hospitalization length .
The posterolateral approach reported shorter surgical duration and hospitalization length .
Concerning the analysis of total estimated blood loss , no significant result was obtained .
***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 For total hip arthroplasty ( THA ) , minimally invasive surgery ( MIS ) uses a smaller incision and less muscle dissection than the classic approach ( CLASS ) , and may lead to faster rehabilitation . Questions / purpose sDoes minimally invasive hip arthroplasty result in superior clinical outcomes ? Patients and Methods In this double-blind r and omized controlled trial , 120 consecutive primary noncemented THAs in 120 patients were assigned to one of two groups ( MIS or CLASS ) . The r and omization sequence was stratified for two groups of surgeons , ie , those using a posterolateral approach ( PL-CLASS or PL-MIS ) and those using an anterolateral approach ( AL-CLASS or AL-MIS ) . Length of the incisions was 18 cm for the CLASS procedures . MIS incisions were extended at the skin level to 18 cm at the end of the procedure . The primary end point was the Harris hip score ( HHS ) at 6 weeks postoperatively . Patient-centered question naires were obtained preoperatively and after 6 weeks and 1 year . Results For the patients in the MIS group ( average 7.8 cm incision length ) , statistically significant increased mean HHSs were seen compared with the CLASS group at 6 weeks and 1 year . This difference was small and mainly caused by the favorable results of the PL-MIS . In the MIS group , surgical time was longer . A learning curve was observed based on operation time and complication rate . Although not statistically significant , the perioperative complication rate was rather high in the ( anterolateral ) MIS group . Conclusions The minimal invasive approach in THA did not show a clinical ly relevant superior outcome in the first postoperative year . Level of Evidence Level I , therapeutic study . See Guidelines for Authors for a complete description of levels of evidence Introduction Minimally invasive total hip arthroplasty ( THA ) is cl aim ed to be superior to the st and ard technique , due to the potential reduction of soft tissue damage via a smaller and tissue-sparing approach . As a result of the lack of objective evidence of fewer muscle and tendon defects , controversy still remains as to whether minimally invasive total hip arthroplasty truly minimizes muscle and tendon damage . Therefore , the objective was to compare the influence of the surgical approach on abductor muscle trauma and to analyze the relevance to postoperative pain and functional recovery . Material s and methods Between June 2006 and July 2007 , 44 patients with primary hip arthritis were prospect ively included in the study protocol . Patients underwent cementless unilateral total hip arthroplasty either through a minimally invasive anterolateral approach ( ALMI ) ( n = 21 ) or a modified direct lateral approach ( mDL ) ( n = 16 ) . Patients were evaluated clinical ly and underwent MR imaging preoperatively and at 3 and 12 months postoperatively . Clinical assessment contained clinical examination , performance of abduction test and the survey of a function score using the Harris Hip Score , a pain score using a numeric rating scale ( NRS ) of 0–10 , as well as a satisfaction score using an NRS of 1–6 . Additionally , myoglobin and creatine kinase were measured preoperatively , and 6 , 24 and 96 h postoperatively . Evaluation of the MRI images included fatty atrophy ( rating scale 0–4 ) , tendon defects ( present/absent ) and bursal fluid collection of the abductor muscle . Results Muscle and tendon damage occurred in both groups , but more lateral gluteus medius tendon defects [ mDL 3/12mth . : 6 (37%)/4 ( 25 % ) ; ALMI : 3 (14%)/2 ( 9 % ) ] and muscle atrophy in the anterior part of the gluteus medius [ mean-st and ard ( 12 ) : 1.75 ± 1.8 ; mean-MIS ( 12 ) : 0.98 ± 1.1 ] were found in patients with the mDL approach . The clinical outcome was also poorer compared to the ALMI group . Significantly , more Trendelenburg ’s signs were evident and lower clinical scores were achieved in the mDL group . No differences in muscle and tendon damage were found for the gluteus minimus muscle . A higher serum myoglobin concentration was measured 6 and 24 h postoperatively in the mDL group ( 6 h : 403 ± 168 μg/l ; 24 h : 304 ± 182 μg/l ) compared to the ALMI group ( 6 h : 331 ± 143 μg/l ; 24 h : 268 ± 145 μg/l ) . Conclusion Abductor muscle and tendon damage occurred in both approaches , but the gluteus medius muscle can be spared more successfully via the minimally invasive approach and is accompanied by a better clinical outcome . Therefore , going through the intermuscular plane , without any detachment or dissection of muscle and tendons , truly minimizes perioperative soft tissue trauma . Furthermore , MRI emerges as an important imaging modality in the evaluation of muscle trauma in THA Benefits of a direct anterior approach ( DAA ) versus a posterior-lateral ( PA ) approach to THA were assessed in a single-surgeon , IRB-approved , prospect i ve , r and omized clinical study . Subjects ( 43 DAA and 44 PA ) were evaluated at 6 weeks , and 3 , 6 and 12 months . The primary end point was ability to climb stairs normally and walk unlimited at each time point . Secondary end points included assessment by several outcome instruments . DAA subjects performed better during the immediate post-operative period ; they had lower VAS pain scores on the first post-operative day , more subjects climbing stairs normally and walking unlimited at 6 weeks , and higher HOOS Symptoms scores at 3 months . There were no significant differences between groups at later time points . Findings confirm previous reports of benefits of DAA versus PA in early post-operative phases The purpose s of this study were to determine the impact of surgical approach on costs of  total hip arthroplasty ( THA )  from a hospital perspective and to provide an up date d cost estimation of THA . A prospect i ve , microcosting analysis was performed on 118 patients undergoing a THA through an anterior , lateral , or posterior approach .  We determined that overall costs ( intraoperative costs and hospital stay ) were significantly less for the anterior ( $ 7300.22 ; 95 % confidence interval [ CI ] , 7064.49 - 7535.95 ) vs lateral ( $ 7853.10 ; 95 % CI , 7577.29 - 8128.91 ; P = .031 ) and anterior vs posterior approach ( $ 8287.46 ; 95 % CI , 7906.42 - 8668.51 ; P < .001 ) . A reduction in hospital length of stay when THA was performed through an anterior approach contributed significantly to an overall reduction in costs from a hospital perspective Objective The aim of the present study was to identify independent preoperative hip function characteristics sensitive for preoperative intervention that are predictive of an extended length of hospital stay ( LOS ) after primary total hip arthroplasty ( THA ) .  Design This is a longitudinal cohort study . A retrospective chart analysis was conducted on prospect ively collected data of patients ( 158 ) who underwent unilateral primary elective cemented THA in a 4-yr period . The main outcome measure was LOS after primary THA . Results The median LOS was 6.0 days . The authors found an 18.5 % increased chance of requiring an LOS of more than 6 days ( odds ratio , 2.15 ; 95 % confidence interval , 1.03–4.50 ) for the patients who needed to use a walking aid preoperatively and a 23.6 % increased chance ( odds ratio , 2.74 ; 95 % confidence interval , 1.31–5.74 ) for the patients who had difficulties managing stairs . Sex , age , body mass index , comorbidity , and preoperative pain did not reach the level of significance in the multivariate analysis . Conclusions Patients who are at risk for a longer stay in the hospital after THA can be identified preoperatively on simple physical function characteristics . These findings enable the identification of appropriate patients for preoperative training to improve functional recovery and decrease the LOS after primary THA Introduction We conducted a prospect i ve study to compare the exposure and implant positioning in primary total hip replacement through the anterolateral minimally invasive ( ALMI ) approach versus the posterior minimally invasive ( PMI ) approach . Material s and methods We applied these techniques to 2 consecutive groups ( 33 and 43 patients , respectively ) comparable preoperatively . All the patients received the same cementless stem and acetabular component . Results There were neither significant difference in femoral or acetabular component positioning nor in limb-length discrepancy . Acetabular exposure was easy through the ALMI approach . Femoral exposure was more difficult as fractures of the trochanter and femoral perforation in our study show . Conclusion For us , exposure and implant positioning through the ALMI approach and the PMI approach are comparable and reliable . However , we recommend caution during the initial learning curve in osteoporotic patients due to the higher rate of peroperative complications for the ALMI approach Background and purpose — Criticism of the lateral approach ( LA ) for hip arthroplasty is mainly based on the risk of poor patient-reported outcomes compared to the posterior approach ( PA ) . However , there have been no controlled studies comparing patient-reported outcomes between them . In this r and omized controlled trial , we tested the hypothesis that patient-reported outcomes are better in patients who have undergone total hip arthroplasty ( THA ) with PA  than in those who have undergone THA with LA , 12 months postoperatively . Patients and methods — 80 patients with hip osteoarthritis ( mean age 61 years ) were r and omized to THA  using  PA or the modified direct LA . We recorded outcome measures preoperatively and 3 , 6 , and 12 months postoperatively using the Hip Disability and Osteoarthritis Outcome Score – Physical Function Short Form ( HOOS-PS ) as the primary outcome . Secondary outcomes were HOOS-Pain , HOOS- Quality -Of-Life , EQ-5D , UCLA Activity Score , and limping . Results — We found no statistically significant difference in the improvements in HOOS-PS between the treatment groups at 12-month follow-up . All secondary outcomes showed similar results except for limping , where PA patients improved significantly more than LA patients . Interpretation — Contrary to our hypothesis , patients treated with PA did not improve more than patients treated with LA regarding physical function , pain , physical activity , and quality of life 12 months postoperatively . However , limping was more pronounced in the LA patients BACKGROUND Minimally invasive total hip arthroplasty has stirred substantial controversy with regard to whether it provides superior outcomes compared with total hip arthroplasty performed through longer incisions . The orthopaedic literature is deficient in well- design ed scientific studies to support the clinical superiority of this approach . The objective of this study was to compare the results of a single mini-incision approach with those of a st and ard-incision total hip arthroplasty in the early postoperative period . METHODS Two hundred and nineteen patients ( 219 hips ) admitted for unilateral total hip arthroplasty between December 2003 and June 2004 were r and omized to undergo surgery through a short incision of < or=10 cm or a st and ard incision of 16 cm .  All patients were blinded to the size of the incision for the duration of the hospital stay . The anesthetic , analgesic , and postoperative physiotherapy protocol s were st and ardized , with the staff also blinded to the technique used . A single surgeon , who had performed more than 300 short-incision hip replacements prior to the start of this study and who performs an average of 415 primary total hip replacements a year , performed all procedures through a single-incision posterior approach using a cementless cup and cemented stem . RESULTS The two groups were matched for age , grade according to the system of the American Society of Anesthesiologists , and body mass index . No significant difference was detected with respect to postoperative hematocrit , blood transfusion requirements , pain scores , or analgesic use . We found no difference in early walking ability or length of hospital stay and no difference in component placement , cement-mantle quality , or functional outcome scores at six weeks . The patient variables significantly associated with a probability of early discharge independent of incision length were patient age and preoperative hemoglobin levels ( p < 0.05 ) . The surgical scars contracted significantly over six weeks ( p < 0.05 ) but by a similar proportion of 11 % to 12 % in both groups . CONCLUSIONS Minimally invasive total hip arthroplasty performed through a single-incision posterior approach by a high-volume hip surgeon with extensive experience in less invasive approaches to the hip is safe and reproducible . However , it offers no significant benefit in the early postoperative period compared with a st and ard incision of 16 cm . As it is not known whether lower-volume and less-experienced surgeons can achieve similar results , the mini-incision technique merits further study before wide dissemination and implementation of this family of surgical approaches can be recommended Purpose The purpose of this study was to evaluate pre-operative education versus no education and mini-invasive surgery versus st and ard surgery to reach complete independence . Methods We conducted a four-arm r and omized controlled trial of 209 patients . The primary outcome criterion was the time to reach complete functional independence . Secondary outcomes included the operative time , the estimated total blood loss , the pain level , the dose of morphine , and the time to discharge . Results There was no significant effect of either education ( HR :  
    Output:
    