***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 A prospect i ve review was performed on 60 consecutive patients with hip hemiarthroplasty after femoral neck fractures . METHODS Twenty-two patients underwent Austin Moore hemiarthroplasty with an intramedullary corticocancellous bone plug at the tip of the prosthesis ( group A ) and 38 patients underwent Austin Moore hemiarthroplasty alone ( group B ) . The patients were evaluated clinical ly and radiographically at 3 and 6 months postoperatively and annually thereafter . RESULTS There was no statistically significant difference in thigh pain score between the two groups . At 3- and 6-month follow-up , 88 % and 83 % of group A patients experienced no pain or mild thigh pain , compared with 72 % and 76 % in group B , respectively . The radiographs revealed more stem subsidence and calcar osteolysis in group B than in group A ( p < 0.01 and p < 0.05 , respectively ) . Furthermore , in both groups there was a correlation between calcar atrophy , stem subsidence , and early clinical thigh pain score ( p < 0.05 ) . CONCLUSION Our data suggest that , whereas the radiologic findings in both groups may be related to thigh pain , they had little effect on the rate of femoral stem revision . We believe that the application of a corticocancellous bone plug in uncemented hip hemiarthroplasty for treatment of femoral neck fractures can decrease the incidence of early thigh pain in the first 6 months Publisher Summary This chapter focuses on the bias in analytic research .  Case-control studies are attractive . They can be executed quickly and at low cost , even when the disorders of interest are rare . The execution of pilot case-control studies is becoming automated ; strategies have been devised for the “ computer scanning ” of large files of hospital admission diagnoses and prior drug exposures , with detailed analyses carried out in the same data set on an ad hoc basis . As evidence of their growing popularity , when one original article was r and omly selected from each issue of The New Engl and Journal of Medicine , The Lancet , and the Journal of the American Medical Association for the years 1956 , 1966 , and 1976 , the proportion that reported case-control analytic studies increased fourfold over these two decades ; however , the proportion reporting cohort analytic studies fell by half ; a general trend toward fewer study subjects but more study authors was also noted Blinding embodies a rich history spanning over two centuries . Most research ers worldwide underst and blinding terminology , but confusion lurks beyond a general comprehension . Terms such as single blind , double blind , and triple blind mean different things to different people . Moreover , many medical research ers confuse blinding with allocation concealment . Such confusion indicates misunderst and ings of both . The term blinding refers to keeping trial participants , investigators ( usually health-care providers ) , or assessors ( those collecting outcome data ) unaware of the assigned intervention , so that they will not be influenced by that knowledge . Blinding usually reduces differential assessment of outcomes ( information bias ) , but can also improve compliance and retention of trial participants while reducing biased supplemental care or treatment ( sometimes called co-intervention ) . Many investigators and readers naïvely consider a r and omised trial as high quality simply because it is double blind , as if double-blinding is the sine qua non of a r and omised controlled trial . Although double blinding ( blinding investigators , participants , and outcome assessors ) indicates a strong design , trials that are not double blinded should not automatically be deemed inferior . Rather than solely relying on terminology like double blinding , research ers should explicitly state who was blinded , and how . We recommend placing greater credence in results when investigators at least blind outcome assessment s , except with objective outcomes , such as death , which leave little room for bias . If investigators properly report their blinding efforts , readers can judge them . Unfortunately , many articles do not contain proper reporting . If an article cl aims blinding without any accompanying clarification , readers should remain sceptical about its effect on bias reduction We report a r and omised , prospect i ve study comparing a st and ard sliding hip screw and the intramedullary hip screw for the treatment of unstable intertrochanteric fractures in the elderly . One hundred and two patients were r and omised on admission to two treatment groups . Fifty-two patients were treated with a compression hip screw ( CHS ) , and fifty had intramedullary fixation with an intramedullary hip screw ( IMHS ) . Patients were followed for 1 year and had a clinical and radiological review at 3 , 6 and 12 months . The mean duration of operation and fluoroscopy screening time was significantly greater for insertion of the intramedullary hip screw . There was no difference between the groups with regard to transfusion requirements or time to mobilise after surgery . There were two technical complications in the CHS group and three in the IMHS group . There was no significant difference between the two groups in radiological or functional outcome at 12 months . It remains to be shown whether the theoretical advantages of intramedullary fixation of extracapsular hip fractures bring a significant improvement in eventual outcome R and omized controlled trials are the gold st and ard for the evaluation of new therapies and surgical procedures and as such require strict attention to study design and statistical analysis . There are , however , multiple challenges in conducting a well- design ed clinical trial . This article describes the difficulties encountered at a single institution participating in a multicenter drug study and review s the challenges involved in developing a high- quality r and omized controlled study BACKGROUND Intramedullary nailing of the femur without reaming of the medullary canal has been advocated as a method to reduce marrow embolization to the lungs and the rate of infection after open fractures . The use of nailing without reaming , however , has been associated with lower rates of fracture-healing . The purpose of this prospect i ve study was to compare the rate of union of femoral shaft fractures following intramedullary nailing with and without reaming . METHODS Two hundred and twenty-four patients were enrolled in a multicenter , prospect i ve , r and omized clinical trial to compare nailing without reaming and nailing with reaming .  One hundred and six patients with 107 femoral shaft fractures were treated with a smaller diameter nail without reaming of the canal , and 118 patients with 121 fractures had reaming of the canal and insertion of a relatively larger diameter nail . Patients were followed at six-week intervals until union occurred or a nonunion was diagnosed . RESULTS The two groups were comparable with regard to the measured patient and injury characteristics . Eight ( 7.5 % ) of the 107 fractures in the group without reaming had a nonunion compared with two ( 1.7 % ) of 121 fractures in the group with reaming ( p = 0.049 ) . The relative risk of nonunion was 4.5 times greater ( 95 % confidence interval = 1 to 20 ) without reaming and with use of a relatively small-diameter nail . CONCLUSION Intramedullary nailing of femoral shaft fractures without reaming results in a significantly higher rate of nonunion compared with intramedullary nailing with reaming The ability of a small-scale r and om-control clinical trial comprising less than 500 patients to disclose clinical ly important differences between treatment groups depends on the event rate in the control group . The high rate of wound infection after abdominal operations has attracted many trials of methods of antibiotic prophylaxis . We review ed all of the pertinent English literature recorded in Index Medicus in 1980 and 1981 . We examined 45 articles for defects in design , analysis , and presentation . Of the 45 articles , 25 reported statistically significant differences between treatment groups and 20 , no significant differences . Unsatisfactory methods of r and omization were used in four trials , ethics were question able in 22 , statistical methods were incorrect in 31 , and presentation was inadequate in 40 . We concluded that there is room for improvement in the conduct of clinical trials Considerable effort is often expended to adjudicate outcomes in clinical trials , but little has been written on the administration of the adjudication process and its possible impact on study results . As a case study , we describe the function and performance of an  adjudication committee  in a large r and omized trial of two diagnostic approaches to potentially operable lung cancer . Up to five independent adjudicators independently determined two primary outcomes : tumor status at death or at final follow-up and the cause of death .  Patients for whom there was any disagreement were discussed in committee until a consensus was achieved . We describe the pattern of agreement among the adjudicators and with the final consensus result . Additionally , we model the adjudication process and predict the results if a smaller committee had been used . We found that reducing the number of adjudicators from five to two or three would probably have changed the consensus outcome in less than 10 % of cases . Correspondingly , the effect on the final study results ( comparing primary outcomes in both r and omized arms ) would have been altered very little . Even using a single adjudicator would not have affected the results substantially . About 90 minutes of person-time per patient was required for activities directly related to the adjudication process , or approximately 6 months of full time work for the entire study . This level of effort could be substantially reduced by using fewer adjudicators with little impact on the results . Thus , we suggest that when high observer agreement is demonstrated or anticipated , adjudication committees should consist of no more than three members . Further work is needed to evaluate if smaller committees are adequate to detect small but important treatment effects or if they compromise validity when the level of adjudicator agreement is lower This paper presents the short term results of an ongoing prospect i ve r and omized trial comparing a cemented unipolar with a cemented bipolar hemiarthroplasty for the treatment of displaced femoral neck fractures in the elderly . Forty-seven patients with an average age of 77 years completed 6-month followup . Outcomes at 6 weeks , 3 months and 6 months were assessed by completion of a patient oriented hip outcome instrument and by functional tests of walking speed and endurance . No differences in the postoperative complication rates or lengths of hospitalization were seen between the two groups . Patients treated with a bipolar hemiarthroplasty had greater range of hip motion in rotation and abduction and had faster walking speeds . However , no differences in hip rating outcomes were found . These early results suggest that use of the less expensive unipolar prosthesis for hemiarthroplasty after femoral neck fracture may be justified in the elderly 
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Trials in orthopaedic trauma typically measure many outcomes requiring judgment , but the individuals assessing those outcomes are seldom blinded .