***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 proximal femoral nail ( PFN ) is a recently introduced intramedullary system , design ed to improve treatment of unstable trochanteric fractures of the hip . In a multicentre prospect i ve clinical study , the intra-operative use , complications and outcome of treatment using the  PFN ( n = 211 ) were compared with those using the gamma nail ( GN ) ( n = 213 ) . The intra-operative blood loss was lower with the PFN ( 220 ml v 287 ml , p = 0.001 ) . Post-operatively , more lateral protrusion of the hip screws of the PFN ( 7.6 % ) was documented , compared with the gamma nail ( 1.6 % , p = 0.02 ) . Most local complications were related to suboptimal reduction of the fracture and /or positioning of the implant . Functional outcome and consolidation were equal for both implants . Generally , the results of treatment of unstable trochanteric fractures were comparable for the PFN and GN . The pitfalls and complications were similar , and mainly surgeon- or fracture-related , rather than implant-related Objective To determine the mortality risk following hip fracture and identify factors predictive of increased mortality . Design Retrospective review of prospect ively collected data . Setting Tertiary care orthopaedic hospital . Background Approximately 250,000 hip fractures occur annually in the United States . The greatest mortality risk following hip fracture has been demonstrated to be within the first 6 months of fracture , and some studies report that the risk approaches expected mortality after 6 months . However , more recent studies have demonstrated that an increased risk of mortality may persist for several years postfracture . The purpose of this study was to assess the excess mortality associated with hip fracture at up to 2 years postinjury . Methods All patients with a hip fracture who were admitted to our institution over a 10-year period were evaluated . Criteria for inclusion included : Caucasian , age 65 or older , previously ambulatory , and home dwelling . Patients were followed prospect ively to determine the mortality risk associated with hip fracture over a 2-year follow-up period . Mortality was compared to a st and ardized population and st and ardized mortality ratios were calculated . Results Eight hundred thirty-six patients met the inclusion criteria and were included .  The mortality risk was highest within the first 3 months following fracture , with st and ardized mortality ratios approaching that of the control population by two years . Patients age 65–84 had higher mortality risk when compared with patients age ≥85 . American Society of Anesthesiologists classification was predictive of increased mortality risk in younger patients , with these patients having triple the mortality risk when compared to the reference population at 2-year follow-up . More elderly patients had minimal excess mortality associated with hip fracture at 1- and 2-year follow-up , regardless of ASA classification . Conclusion The data demonstrate that hip fracture is not associated with significant excess mortality amongst patients older than age 85 . Amongst younger patients , however , those with ASA classifications of 3 or 4 have significant excess mortality following hip fracture that persists up to 2 years after injury Objectives : We sought to examine the relationship between functional outcome and process of care for patients with hip fracture . Research Design and Participants : We undertook a prospect i ve cohort study in 4 hospitals of 554 patients treated with surgery for hip fracture . Measurements : Information on patient characteristics and processes of hospital care collected from the medical record , interviews , and bedside observations . Follow-up information obtained at 6 months on function ( using the Functional Independence Measure [ FIM ] ) , survival , and readmission . Results : Individual processes of care were generally not associated with adjusted outcomes . A scale of 9 processes related to mobilization was associated with improved adjusted locomotion ( P = 0.006 ) , self care ( P = 0.022 ) , and transferring ( P = 0.007 ) at 2 months , but the benefits were smaller and not significant by 6 months . These processes were not associated with mortality . The predicted value for the FIM locomotion measure ( range , 2–14 ) at 2 months was 5.9 ( 95 % confidence interval 5.4–6.4 ) for patients at the 10th percentile of performance on these processes compared with 7.1 ( 95 % confidence interval 6.6 , 7.6 ) at the 90th percentile . Patients who experienced no hospital complications and no readmissions retained the benefits in locomotion at 6 months . Anticoagulation processes were associated with improved transferring at 2 months ( P = 0.046 ) but anticoagulation and other processes of care were not otherwise associated with improved function . Discussion : Our findings indicate the need to attend to all steps in the care of patients with hip fracture . Additionally , functional outcomes were more sensitive markers of improved process of care , compared with 6-month mortality , in the case of hip fracture OBJECTIVES To identify determinants of mortality and institutionalization after hip fracture and to identify those older hip fracture patients at high risk of death or institutionalization after hip fracture . DESIGN Population -based prospect i ve inception cohort study of hip fracture patients ; patients were assessed in the hospital and at 3 months following the hip fracture . SETTING Edmonton area hip fracture patients admitted to one of two Edmonton , Alberta , Canada , acute care centers between July 10 , 1996 , and August 31 , 1997 . PARTICIPANTS Patients were residents of the Edmonton area and over the age of 64 . Those who had previously fractured the same hip within the past 5 years or had some pathological condition underlying the hip fracture were excluded . Of 610 eligible patients , 558 contributed some baseline information and were included in the mortality analysis ; the institutionalization analysis was restricted to the 338 patients who lived in the community before fracture , survived the 3-month period postfracture , and had completed a 3-month follow-up interview . MEASUREMENTS The baseline interview was done in the hospital to assess mental status , prefracture physical function , prefracture health perception , and prefracture social support . The 3-month follow-up interview was done by phone to assess physical function , health perception , and social support 3 months postfracture . Demographic and comorbidity information was collected from medical records . RESULTS Low mental status in hospital was found to increase the chances of mortality and institutionalization , and male gender was found to increase mortality risk fourfold . Each additional 10 years of age increased the risk of institutionalization approximately 2.5 times . Patients with lower postfracture physical function had at least five times the risk of institutionalization compared to patients with high postfracture physical function . CONCLUSIONS Cognitive impairment , older age , and gender were associated with increased risk of poor outcome following hip fracture . The socioeconomic variables -- social support and health perception -- did not contribute significant additional information in explaining mortality or institutionalization risk . While demographic factors can not be modified , physical function 3 months postfracture may be amenable to intervention and may reduce the risk of institutionalization . Intervening to increase postfracture physical function may be particularly beneficial to older patients , or to those who are cognitively impaired This prospect i ve r and omized trial compared the efficacy of unipolar versus bipolar hemiarthroplasty in elderly patients ( ≥ 65 years ) with displaced femoral neck fractures in terms of quality of life and functional outcomes . One hundred fifteen patients with a mean age of 82.1 years were enrolled in this study and r and omized to either unipolar or bipolar hemiarthroplasty .  Quality of life and functional outcomes were assessed using the Musculoskeletal Functional Assessment instrument and Short Form-36 health survey .  Seventy-eight patients completed 1 year of followup . There were no differences between the groups in estimated blood loss , length of hospital stay , mortality rate , number of dislocations , postoperative complications , or ambulatory status at 1 year . There also were no significant differences between the two groups at either point in postoperative Short Form-36 or Musculoskeletal Functional Assessment instrument scores . Results of this prospect i ve r and omized study suggest that the bipolar endoprosthesis provides no advantage in the treatment of displaced femoral neck fractures in elderly patients  regarding quality of life and functional outcomes A prospect i ve , r and omized trial of 104 consecutive patients with displaced fractures of the femoral neck treated with either a sliding screw plate or four AO cancellous bone screws  was performed to study the influence of the fixation device and the fixation procedure on the vascularity of the femoral head . The vitality of the femoral head was determined by 99mTc-MDP scintigraphy performed 2 - 3 months after the operation . Eighty-seven patients ( 84 per cent ) were available for assessment . The two treatment groups were comparable with regard to age , degree of primary displacement and quality of reduction . There were significantly more ( P less than 0.01 ) avascular femoral heads or femoral heads with reduced vascularity in the sliding screw plate group ( 14/40 , 35 per cent ) than in the four AO cancellous bone screw group ( 5/47 , 11 per cent ) Abstract Objectives To evaluate postoperative medical complications and the association between these complications and mortality at 30 days and one year after surgery for hip fracture and to examine the association between preoperative comorbidity and the risk of postoperative complications and mortality . Design Prospect i ve observational cohort study . Setting University teaching hospital . Participants 2448 consecutive patients admitted with an acute hip fracture over a four year period . We excluded 358 patients : all those aged < 60 ; those with periprosthetic fractures , pathological fractures , and fractures treated without surgery ; and patients who died before surgery . Interventions Routine care for hip fractures . Main outcome measures Postoperative complications and mortality at 30 days and one year . Results Mortality was 9.6 % at 30 days and 33 % at one year . The most common postoperative complications were chest infection ( 9 % ) and heart failure ( 5 % ) . In patients who developed postoperative heart failure mortality was 65 % at 30 days ( hazard ratio 16.1 , 95 % confidence interval 12.2 to 21.3 ) . Of these patients , 92 % were dead by one year ( 11.3 , 9.1 to 14.0 ) . In patients who developed a postoperative chest infection mortality at 30 days was 43 % ( 8.5 , 6.6 to 11.1 ) . Significant preoperative variables for increased mortality at 30 days included the presence of three or more comorbidities ( 2.5 , 1.6 to 3.9 ) , respiratory disease ( 1.8 , 1.3 to 2.5 ) , and malignancy ( 1.5 , 1.01 to 2.3 ) . Conclusions In elderly people with hip fracture , the presence of three or more comorbidities is the strongest preoperative risk factor . Chest infection and heart failure are the most common postoperative complications and lead to increased mortality . These groups offer a clear target for specialist medical assessment We analysed the time-dependent mean changes in the femoral neck length , neck-shaft angle and hip offset in a r and omised study comprising 48 patients who were treated with the dynamic hip screw ( DHS ) or the proximal femoral nail ( PFN ) for an unstable intertrochanteric femoral fracture . As a consequence of fracture compression , the mean post-operative neck length was significantly shorter in patients treated with the DHS . During the first 6 weeks after the operation , a mean decrease of 4.6 ° was observed in the neck-shaft angle , but there was not a significant difference between the treatment groups . The radiographic measures remained virtually unaffected during the interval from 6 weeks to 4 months in both groups . When the operated hip was compared to the opposite hip , patients who had received the DHS showed significantly greater medialisation of the femoral shaft at 4 months than those treated with the PFN . We thus recommend that unstable intertrochanteric fractures should be initially reduced in a slight valgus position in order to achieve an outcome after healing that is as normal as possible . As a result of differences in operative technique and implant stability , the PFN may be superior to the DHS in retaining the anatomical relations in the hip region in unstable intertrochanteric fractures . RésuméNous avons analysé les modifications , en fonction du temps , des valeurs moyennes de la longueur du col fémoral , de l’angle cervico-diaphysaire et du bras de levier de la hanche dans une étude r and omisée qui comprenait 48 malades traités avec une Vis Dynamique ( DHS )  ou un Clou Fémoral Proximal ( PFN ) aprés une fracture intertrochantérienne instable . Par suite de la compression de la fracture , la longueur du col était nettement plus courte chez les malades traités avec une DHS . Pendant les premières six semaines après l’opération , une baisse moyenne de 4.6 ° de l’angle cervico-diaphysaire a été observée mais il n’y avait pas de différence notable entre les groupes de traitement . Les mesures radiographiques sont restées pratiquement non affectées pendant l’intervalle de six semaines à quatre mois dans les deux groupes . Comparé à la hanche opposée , les malades qui avaient reçu une DHS ont montré à 4 mois une nettement plus gr and e médialisation de la diaphyse que ceux traités avec le PFN . Nous recomm and ons que ces fractures intertrochantériennes instables soient réduites en léger valgus pour avoir une situation aussi norm 
    Output:
    
Fracture type does not appear to be independently related to patient outcomes .
Mortality , pain , function , and quality of life did not differ by surgical implant class , or by implants within a class .