***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: OBJECTIVES Femoroacetabular impingement is proposed to cause early osteoarthritis ( OA ) in the non-dysplastic hip . We previously reported on the prevalence of femoral deformities in a young asymptomatic male population . The aim of this study was to determine the prevalence of both femoral and acetabular types of impingement in young females . METHODS We conducted a population -based cross-sectional study of asymptomatic young females . All participants completed a set of question naires and underwent clinical examination of the hip . A r and om sample was subsequently invited to obtain magnetic resonance images ( MRI ) of the hip . All MRIs were read for cam-type deformities , increased acetabular depths , labral lesions , and impingement pits . Prevalence estimates of cam-type deformities and increased acetabular depths were estimated , and relationships between deformities and signs of joint damage were examined using logistic regression models . RESULTS The study included 283 subjects , and 80 asymptomatic females with a mean age of 19.3 years attended MRI .  Fifteen showed some evidence of cam-type deformities , but none were scored to be definite . The overall prevalence was therefore 0 % [ 95 % confidence interval ( 95 % CI ) 0 - 5 % ] . The prevalence of increased acetabular depth was 10 % ( 95 % CI 5 - 19 ) . No association was found between increased acetabular depth and decreased internal rotation of the hip . Increased acetabular depth was not associated with signs of labral damage . CONCLUSIONS Definite cam-type deformities in women are rare compared to men , whereas the prevalence of increased acetabular depth is higher , suggesting that femoroacetabular impingement has different gender-related biomechanical mechanisms BACKGROUND The conduct of r and omized , controlled trials of nonpharmacologic treatments presents specific challenges that are not adequately addressed in trial reports . OBJECTIVE To develop an extension of the CONSORT ( Consoli date d St and ards of Reporting Trials ) Statement for trials of nonpharmacologic treatments . DESIGN A consensus meeting was organized to develop an extension of the CONSORT Statement that addresses r and omized trials of nonpharmacologic treatments . To prepare for the meeting , a survey was conducted to identify the specific issues for discussion . SETTING Consensus meeting in Paris , France . PARTICIPANTS A total of 33 experts attended the meeting . The experts were method ologists ( n = 17 ) ; surgeons ( n = 6 ) ; editors ( n = 5 ) ; and clinicians involved in rehabilitation ( n = 1 ) , psychotherapy ( n = 2 ) , education ( n = 1 ) , and implantable devices ( n = 1 ) . MEASUREMENTS Experts indicated which of the 22 items on the CONSORT checklist should be modified or which additional items should be added specifically for nonpharmacologic treatments . During a 3-day consensus meeting , all items were discussed and additional method ological issues related to nonpharmacologic research were identified . RESULTS The consensus was that 11 items on the CONSORT checklist needed some modifications for nonpharmacologic trials : item 1 ( title and abstract ) , item 3 ( participants ) , item 4 ( interventions ) , item 7 ( sample size ) , item 8 ( r and omization ) , item 11 ( blinding ) , item 12 ( statistical methods ) , item 13 ( participant flow ) , item 15 ( baseline data ) , item 20 ( discussion : interpretation ) , and item 21 ( generalizability ) . In addition , the meeting participants added 1 item related to implementation of the intervention . LIMITATION Evidence was not always available to support the inclusion of each checklist item . CONCLUSION The methods and processes used to develop this extension could be used for other reporting guidelines . The use of this extension to the CONSORT Statement should improve the quality of reporting r and omized , controlled trials assessing nonpharmacologic treatments Background Surgical placebos are controversial . This in-depth study explored the design , acceptability , and feasibility issues relevant to design ing a surgical placebo-controlled trial for the evaluation of the clinical and cost effectiveness of arthroscopic lavage  for the management of people with osteoarthritis of the knee in the UK . Methods Two surgeon focus groups at a UK national meeting for orthopaedic surgeons and one regional surgeon focus group ( 41 surgeons ) ; plenary discussion at a UK national meeting for orthopaedic anaesthetists ( 130 anaesthetists ) ; three focus groups with anaesthetists ( one national , two regional ; 58 anaesthetists ) ; two focus groups with members of the patient organisation Arthritis Care ( 7 participants ) ; telephone interviews with people on consultant waiting lists from two UK regional centres ( 15 participants ) ; interviews  with Chairs of UK ethics committees ( 6 individuals ) ; postal surveys of members of the British Association of Surgeons of the Knee ( 382 surgeons ) and members of the British Society of Orthopaedic Anaesthetists ( 398 anaesthetists ) ; two centre pilot ( 49 patients assessed ) . Results There was widespread acceptance that evaluation of arthroscopic lavage  had to be conducted with a placebo control if scientific rigour was not to be compromised . The choice of placebo  surgical  procedure ( three small incisions ) proved easier than the method of anaesthesia ( general anaesthesia ) . General anaesthesia , while an excellent mimic , was more intrusive and raised concerns among some stakeholders and caused extensive discussion with local decision-makers when seeking formal approval for the pilot . Patients were willing to participate in a pilot with a placebo arm ; although some patients when allocated to surgery became apprehensive about the possibility of receiving placebo , and withdrew . Placebo surgery was undertaken successfully . Conclusions Our study illustrated the opposing and often strongly held opinions about surgical placebos , the ethical issues underpinning this controversy , and the challenges that exist even when ethics committee approval has been granted . It showed that a placebo-controlled trial could be conducted in principle , albeit with difficulty . It also highlighted that not only does a placebo-controlled trial in surgery have to be ethically and scientifically acceptable but that it also must be a feasible course of action . The place of placebo-controlled surgical trials more generally is likely to be limited and require specific circumstances to be met . Suggested criteria are presented . Trial registration numberThe trial was assigned IS RCT N02328576 through http://controlled-trials.com/ in June 2006 . The first patient was r and omised to the pilot in July 2007 The benefit of arthroscopy of the hip in the treatment of femoroacetabular impingement ( FAI ) in terms of quality of life ( QoL ) has not been reported . We prospect ively collected data on 612 patients ( 257 women ( 42 % ) and 355 men ( 58 % ) ) with a mean age at the time of surgery of 36.7 years ( 14 to 75 ) who underwent arthroscopy of the hip for FAI under the care of a single surgeon . The minimum follow-up was one year ( mean 3.2 years ( 1 to 7 ) ) . The responses to the modified Harris hip score were translated using the Rosser Index Matrix in order to provide a QoL score . The mean QoL score increased from 0.946 ( -1.486 to 0.995 ) to 0.974 ( 0.7 to 1 ) at one year after surgery ( p < 0.001 ) . The mean QoL score in men was significantly higher than in women , both before and one year after surgery ( both p < 0.001 ) . However , the mean change in the QoL score was not statistically different between men and women ( 0.02 ( -0.21 to 0.27 ) and 0.04 ( -0.16 to 0.87 ) , respectively ; p = 0.12 ) . Linear regression analysis revealed that the significant predictors of a change in QoL score were pre-operative QoL score ( p < 0.001 ) and gender ( p = 0.04 ) . The lower the pre-operative score , the higher the gain in QoL post-operatively ( ρ = -0.66 ; p < 0.001 ) . One year after surgery the QoL scores in the 612 patients had improved in 469 ( 76.6 % ) , remained unchanged in 88 ( 14.4 % ) and had deteriorated in 55 ( 9.0 % ) Objectives The number of surgical procedures performed each year to treat femoroacetabular impingement ( FAI ) continues to rise . Although there is evidence that surgery can improve symptoms in the short-term , there is no evidence that it slows the development of osteoarthritis ( OA ) . We performed a feasibility study to determine whether patient and surgeon opinion was permissive for a R and omised Controlled Trial ( RCT ) comparing operative with non-operative treatment for FAI . Methods Surgeon opinion was obtained using  vali  date d question naires at a Specialist Hip Meeting ( n = 61 , 30 of whom stated that they routinely performed FAI surgery ) and patient opinion was obtained from clinical patients with a new diagnosis of FAI ( n = 31 ) . Results Clinical equipoise was demonstrated when surgeons were given clinical scenarios and asked whether they would manage a patient operatively or non-operatively . A total of 23 surgeons ( 77 % ) who routinely perform FAI surgery were willing to recruit patients into a RCT , and 28 patients ( 90 % ) were willing to participate . 75 % of responding surgeons believed it was appropriate to r and omise patients to non-operative treatment for ≥ 12 months . Conversely , only eight patients ( 26 % ) felt this was acceptable , although 29 ( 94 % ) were willing to continue non-operative treatment for six months . More patients were concerned about their risk of developing OA than their current symptoms , although most patients felt that the two were of equal importance . Conclusions We conclude that a RCT comparing operative and non-operative management of FAI is feasible and should be considered a research priority . An important finding for orthopaedic surgical trials is that patients without life-threatening pathology appear willing to trial a treatment for six months without improvement in their symptoms OBJECTIVES To ascertain the acceptability of a r and omised controlled trial comparing arthroscopic lavage with a placebo-surgical procedure for the management of  osteoarthritis of the knee ; and to assess the practical feasibility of mounting such a multicentre placebo-controlled trial . DESIGN Mixed methods study including : focus groups with surgeons and anaesthetists ; focus groups and interviews with potential participants ; interviews with chairpersons of UK Multicentre Research Ethics Committees ( MRECs ) ; surveys of surgeons and anaesthetists ; and a two-centre , three-arm pilot . SETTING UK secondary care . PARTICIPANTS Members of the British Association of Surgeons of the Knee and members of the British Society of Orthopaedic Anaesthetists took part in the focus groups and surveys . Surgeons and anaesthetists from two regional centres in the UK also contributed to focus groups , as did patients from consultant lists in two UK regional centres , and members of Arthritis Care . Chairpersons of six UK MRECs were interviewed . Participants were eligible for the pilot if they were adults ( 18 years or older ) with radiological evidence of osteoarthritis of the knee who might be considered for arthroscopic lavage , and were fit for general anaesthetic ( defined by the American Society of Anaesthesiologists grade s 1 and 2 ) , and able to give informed consent . INTERVENTIONS Participants in the pilot study were r and omised to arthrosocopic lavage  ( with or without debridement at the clinical discretion of the surgeon ) ; placebo surgery ; or non-operative management with specialist re assessment . MAIN OUTCOME MEASURES The acceptability and feasibility of mounting a  placebo-controlled trial for the evaluation of knee  arthroscopic lavage .  RESULTS There was broad acceptance across all stakeholder groups of the need to find out more about the effectiveness of arthroscopic lavage . Despite this there was variation in opinion within all the groups about how research ers should approach this and whether or not it would be acceptable to investigate using placebo surgery . Within the health professional groups , there tended to be a split between those who were strongly opposed to the inclusion of a placebo surgery arm and those who were more in favour . For prospect i ve trial participants who had osteoarthritis of the knee , the acceptability of the trial was discussed from a more individual perspective - reflecting on their personal reasons for or against participating . The majority of this group said they would consider taking part . The pilot study showed that , in principle , a placebo-controlled trial could be conducted . It showed that patients were willing to participate in a trial which would involve a placebo-surgical arm and that it was possible to undertake placebo surgery successfully and to blind patients to their allocation - although once patients knew their allocation , some patients allocated to surgery became more concerned about the possibility of undergoing placebo surgery , and withdrew . The experience of the pilot , however , showed that , despite full MREC approval , the study required major discussion and negotiation before local clinical approvals could be obtained . The fact that ethics approval had been granted did not mean that clinicians would automatically accept that the process was ethical . CONCLUSIONS The study showed that , in principle , a placebo-controlled trial of arthroscopic lavage could be conducted in the UK , albeit with difficulty . Against the background of falling use of arthroscopic lavage the decision was , therefore , taken not to proceed to full-scale trial for this procedure . The study showed that for some health professionals the use of 
    Output:
    
AUTHORS ' CONCLUSIONS There is no high quality evidence examining the effectiveness of surgery for femoroacetabular impingement .