***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 Humeral shaft fractures account for 1 - 3 % of all fractures and 20 % of the fractures involving the humerus . The aim of the current study was to compare the outcome after operative and non-operative treatment of humeral shaft fractures , by comparing the time to radiological union and the rates of delayed union and complications . METHODS All patients aged 16 years or over treated for a humeral shaft fracture during a 5-year period were included in this retrospective analysis ; periprosthetic and pathological fractures were excluded .  Radiographs and medical charts were retrieved and review ed in order to collect data on fracture classification , time to radiographic consolidation and the occurrence of adverse events . RESULTS A total of 186 patients were included ; 91 were treated non-operatively and 95 were treated operatively . Mean age was 58.7 ± 1.5 years and 57.0 % were female . In 83.3 % of the patients , only the humerus was affected . A fall from st and ing height was the most common cause of the fracture ( 72.0 % ) . Consolidation time varied from a median of 11 - 28 weeks . The rate of radial nerve palsy in both groups was similar : 8.8 % versus 9.5 % . In 5.3 % of the operatively treated patients , the palsy result ed from the operation . Likewise , delayed union rates were similar in both groups : 18.7 % following non-operative treatment versus 18.9 % following surgery . CONCLUSION The data indicated that consolidation time and complication rates were similar after operative and non-operative treatment . A prospect i ve r and omised clinical trial comparing non-operative with operative treatment is needed in order to examine other aspects of outcome , meaning shoulder and elbow function , postoperative infection rates , trauma-related quality of life and patient satisfaction Background : Nonoperative treatment has historically been considered the st and ard for fractures of the shaft of the humerus . Minimally invasive bridge-plate osteo synthesis for isolated humeral shaft fractures has been proven to be a safe technique , with good and reproducible results . This study was design ed to compare clinical and radiographic outcomes between patients who had been treated with bridge plate osteo synthesis and those who had been managed nonoperatively with a functional brace . Methods : A prospect i ve r and omized trial was design ed and included 110 patients allocated to 1 of 2 groups : surgery with a bridge plate or nonoperative treatment with a functional brace . The primary outcome was the Disabilities of the Arm , Shoulder and H and ( DASH ) score at 6 months . The score on the Short Form-36 ( SF-36 ) life- quality question naire , complications of treatment , Constant-Murley score for the shoulder , pain level , and radiographic results were assessed as secondary outcomes . Participants were assessed at 2 weeks ; 1 , 2 , and 6 months ; and 1 year after the interventions . Results : The mean DASH score of the bridge plate group was statistically superior to that of the functional brace group ( mean scores , 10.9 and 16.9 , respectively ; p = 0.046 ) only at 6 months . The bridge plate group also had a significantly more favorable nonunion rate ( 0 % versus 15 % ) and less mean residual angular displacement seen on the anteroposterior radiograph ( 2.0 ° versus 10.5 ° ) ( both p < 0.05 ) . No difference between the groups was detected with regard to the SF-36 score , pain level , Constant-Murley score , or angular displacement seen on the lateral radiograph . Conclusions : This trial demonstrates that , compared with functional bracing , surgical treatment with a bridge plate has a statistically significant advantage , of uncertain clinical benefit , with respect to self-reported outcome ( DASH score ) at 6 months , nonunion rate , and residual deformity in the coronal plane as seen on radiographs . Level of Evidence : Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence Background : Because of specific method ological difficulties in conducting r and omized trials , surgical research remains dependent predominantly on observational or non‐r and omized studies . Few vali date d instruments are available to determine the method ological quality of such studies either from the reader 's perspective or for the purpose of meta‐ analysis . The aim of the present study was to develop and vali date such an instrument BACKGROUND In the hierarchy of research design s , the results of r and omized , controlled trials are considered to be evidence of the highest grade , whereas observational studies are viewed as having less validity because they reportedly overestimate treatment effects . We used published meta-analyses to identify  r and omized clinical trials and observational studies that examined the same clinical topics . We then compared the results of the original reports according to the type of research design . METHODS A search of the Medline data base for articles published in five major medical journals from 1991 to 1995 identified meta-analyses of r and omized , controlled trials and meta-analyses  of either cohort or case-control studies that assessed the same intervention . For each of five topics , summary estimates and 95 percent confidence intervals were calculated on the basis of data from the individual r and omized , controlled trials and the individual observational studies . RESULTS For the five clinical topics and 99 reports evaluated , the average results of the observational studies were remarkably similar to those of the r and omized , controlled trials . For example , analysis of 13 r and omized , controlled trials of the effectiveness of bacille  Calmette-Guérin vaccine in preventing active tuberculosis yielded a relative risk of 0.49 ( 95 percent confidence interval , 0.34 to 0.70 ) among vaccinated patients , as compared with an odds ratio of 0.50 ( 95 percent confidence interval , 0.39 to 0.65 ) from 10 case-control studies . In addition , the range of the point estimates for the effect of vaccination was wider for the r and omized , controlled trials ( 0.20 to 1.56 ) than for the observational studies ( 0.17 to 0.84 ) . CONCLUSIONS The results of well- design ed observational studies ( with either a cohort or a case-control design ) do not systematic ally overestimate the magnitude of the effects of treatment as compared with those in r and omized , controlled trials on the same topic PURPOSE The aim of this study is to examine the demographic factors , functional outcome and radiological data to predict the outcome of humeral diaphyseal fractures . METHODS We performed a prospect i ve study on a consecutive series of 110 patients of 16 years or over , who had sustained a humeral diaphyseal fracture . There were 42 males and 68 females , with an average age of 59 years ( range 16 - 93 years ) . A total of 72 % sustained low-energy injuries , and 89 patients ( 81 % ) were primarily treated non-operatively . Shoulder function was assessed using the Neer 's and Constant 's scores at 8 weeks , 3 months , 6 months and 1 year after injury . Muscle strength was determined isokinetically using a Biodex System 2 dynamometer . Non-union was defined as a failure to bridge at least three cortices and persistence of tenderness or mobility at the fracture site 16 weeks after fracture . RESULTS Sixteen patients ( 17 % ) had non-union at 16 weeks , while 80 had achieved union and a further 14 were lost to follow-up . After stepwise multiple linear regression was performed to isolate independent factors affecting outcome , only the presence of a proximal diaphyseal fracture was found to predict non-union along with a poor Neer 's score at 8 and 12 weeks . Poor Neer 's scores could be predicted at 26 weeks by age ( P<0.05 ) , previous stroke ( P<0.001 ) and non-union ( P<0.001 ) . At 52 weeks both age ( P<0.01 ) and previous stroke ( P<0.01 ) were independently predictive of poorer Neer 's scores . Malunion of any degree had no detectable effect on function . CONCLUSIONS Our results indicate that non-union of humeral diaphyseal fractures can be predicted in the presence of a proximal third fracture with a Neer 's score of less than 45 by 12 weeks after fracture . Early surgery improves early function , but this is not a lasting effect . Poor shoulder function is predicted by increasing age , proximal third fractures and non-union . We recommend that surgery to promote union be considered at 12 weeks after fracture in fit patients with fractures of the proximal third of the humerus , poor Neer 's scores  and no radiographic progression to union Objective : The primary aim was to describe the epidemiology of the  Holstein-Lewis humeral shaft fracture  , its association with radial nerve palsy , and the outcome regarding recovery from the radial nerve palsy and fracture healing . The secondary aim was to analyze the long-term functional outcome . Setting : Six major hospitals in Stockholm County . Design : Descriptive study . Retrospective assessment of radial nerve recovery and fracture healing . Prospect i ve assessment of functional outcome . Patients : Twenty-seven patients with a 12A1.3 humeral shaft fracture according to the OTA classification satisfying the criteria of a Holstein-Lewis fracture in a population of 358 patients with 361 traumatic humeral shaft fractures . Intervention : Nonoperative or operative treatment according to the decision of the attending orthopaedic surgeon . Main Outcome Measurements : Recovery of the radial nerve , fracture healing , and functional outcome according to the Short Musculoskeletal Function Assessment ( SMFA ) . Results : The Holstein-Lewis humeral shaft fracture constitutes 7.5 % of all humeral shaft fractures and was associated with an increased risk of acute radial nerve palsy compared with other types of humeral shaft fractures , 22 % versus 8 % ( P < 0.05 ) . The fractures of 6 of the 7 operatively treated patients healed after the primary surgical procedure while 1 fracture healed after revision surgery . The fractures of all patients treated nonoperatively healed without any further intervention . All 6 radial nerve palsies ( 2 patients treated nonoperatively and 4 operatively ) recovered . The functional outcome according to the SMFA was good with no differences between the nonoperatively and operatively treated patients : SMFA dysfunction index 7.6 and 9.7 , respectively , and SMFA bother index 6.1 and 6.8 , respectively . Conclusions : The Holstein-Lewis humeral shaft fracture was associated with a significantly increased risk of acute radial nerve palsy . The overall outcome regarding fracture healing , radial nerve recovery , and function was very good regardless of the primary treatment modality , that is , operative or nonoperative treatment . The indication for primary operative intervention in this fracture type appears to be relative Summary . A comparison was made between 44 humeral fractures treated conservatively with functional bracing ( Group 1 ) and 45 treated by operation with a locking nail ( Group 2 ) . Thirty-eight of the 44 patients in Group 1 ( 86 % ) and 22 of the 45 patients in Group 2 ( 47 % ) regained full movement of the shoulder joint . The functional end results were somewhat better in Group 1 although over 90 % of patients in both groups were able to clasp their fingers behind their necks and to reach up their backs without restriction . Two patients developed a pseudarthrosis in Group 1 , and 2 patients in Group 2 required operative revision due to a haematoma in 1 case and as a result of an infection in the other . There were 6 cases of primary radial nerve damage in both groups , and 6 had to be decompressed operatively . Residual sensory and motor disturbance remained in 2 patients in Group 1 . Both methods are useful for the treatment of humeral shaft fractures . We advocate functional bracing as the method of choice if no contraindications exist . Résumé . 99 fractures de la diaphyse humérale ont été analysées , do nt 44 ont été traitées par brassard et 45 par clou intramédullaire . 86 % du groupe : traitement conservateur et 47 % du groupe : traitement opératoire présentaient un mouvement illimité de l’épaule , t and is que plus de 90 % des deux groupes arrivaient à toucher la nuque ( rotation externe en abduction ) et la sacrum ( rotation interne en adduction ) avec la main du bras blessé . Il y a eut deux pseudarthroses dans le groupe conservateur . Dans le groupe opératoire deux interventions chirurgicales ont été nécessaires en raison d’une infection et d’une hémorragie . Les deux groupes présentaient chacun 6 cas de paralysie primaire du nerf radial avec une décompression chirurgicale consécutive dans 6 cas . Des déficits moteurs et sensitifs persistaient chez deux malades du groupe conservateur . Les deux méthodes sont efficaces pour le traitement des fractures de la diaphyse de l’humérus . En cas d’absence des contre-indications nous recomm and ons le traitement par brassard comme traitement de premier choix BACKGROUND : For many years it has been cl aim ed that observational studies find stronger treatment effects than r and omized , controlled trials . We compared the results of observational studies with those of r and omized , controlled trials . METHODS : We search ed the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition . We then search ed the Medline and Cochrane data bases to identify all the r and omized , controlled trials and observational studies comparing the same treatments for these conditions . For 
    Output:
    
There appeared to be no difference in mean time to union and mean Disabilities of the Arm , Shoulder and H and scores between the treatment groups .
No difference was found between effect estimates form observational studies and RCTs .
This systematic review shows that satisfactory results can be achieved with both conservative and operative management ; however , operative treatment reduces the risk of nonunion compared with conservative treatment , with comparable reintervention rates ( for indications other than nonunion ) .
Furthermore , operative treatment results in a similar permanent radial nerve palsy rate , despite its inherent additional surgery-related risks .