***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 The prevalence and risk factors for recurrent instability and functional impairment following a primary glenohumeral dislocation remain poorly defined in younger patients . We performed a prospect i ve cohort study to evaluate these outcomes . We also aim ed to produce guidelines for the design of future clinical trials , assessing the efficacy of interventions design ed to improve the outcome after a primary dislocation . METHODS We performed a prospect i ve cohort study of 252 patients ranging from fifteen to thirty-five years old who sustained an anterior glenohumeral dislocation and were treated with sling immobilization , followed by a physical therapy program . Patients received regular clinical follow-up to assess whether recurrent instability had developed . Functional assessment s were made and were compared for two subgroups : those who had not had instability develop and those who had received operative stabilization to treat recurrent instability . RESULTS On survival analysis , instability developed in 55.7 % of the shoulders within the first two years after the primary dislocation and increased to 66.8 % by the fifth year . The younger male patients were most at risk of instability , and 86.7 % of all of the patients known to have recurrent instability had this complication develop within the first two years . A small but measurable degree of functional impairment was present at two years after the initial dislocation in most patients . Sample -size calculations revealed that a relatively small number of patients with a primary dislocation would be required in future clinical trials examining the effects of interventions design ed to reduce the prevalence of recurrent instability and improve the functional outcome . CONCLUSIONS Recurrent instability and deficits of shoulder function are common after primary nonoperative treatment of an anterior shoulder dislocation . There is substantial variation in the risk of instability , with younger males having the highest risk and females having a much lower risk . Future clinical trials to evaluate primary interventions should evaluate the prevalence of recurrent instability and functional deficits , with use of an assessment tool specifically for shoulder instability , during the first two years after the initial dislocation There are many measurement tools for assessing patients ’ shoulder symptoms ( pain ) and function  ( what patients can do ) , but they do not measure activity ( how often a patient engages in activity ) . This is relevant because activity level can have an important impact on a patient ’s outcome . Our goal was to develop a short , easy to administer measure of shoulder activity which could be used to predict outcome of shoulder disorders . The activity scale was developed using established principles : item generation , item reduction , pretesting , and reliability and validity testing . The activity rating is a numerical sum of scores for five activities rated on a five-point frequency scale from never performed ( 0 points ) to daily ( 4 points ) . Patients were scored on the following criteria : carrying an object 8 lb or heavier  by h and , h and ling objects overhead ,  weight training with arms , swinging motion ( ie , hitting tennis or golf ball ) , and lifting objects 25 lb or heavier . Two additional multiple choice questions provide a score assessing participation in contact and overhead sports . The activity scale showed excellent reliability and construct validity . It can be completed quickly and used in conjunction with patient-based measures of shoulder outcome to define patient population s for cohort studies , and to assess activity level as a prognostic factor in patients with shoulder disorders . Level of Evidence : Prognostic study , Level I. See the Guidelines for Authors for a complete description of levels of evidence BACKGROUND Anterior dislocation of the glenohumeral joint in younger patients is associated with a high risk of recurrence and persistent functional deficits . The aim of this study was to assess the efficacy of a primary arthroscopic Bankart repair , while controlling for the therapeutic effects produced by the arthroscopic intervention and joint lavage . METHODS In a single-center , double-blind clinical trial , eighty-eight adult patients under thirty-five years of age who had sustained a primary anterior glenohumeral dislocation were r and omized to receive either an arthroscopic examination and joint lavage alone or together with an anatomic repair of the Bankart lesion .  Assessment of the rate of recurrent instability , functional outcome ( with use of three scores ) , range of movement , patient satisfaction , direct health-service costs , and treatment complications was completed for eighty-four of these patients ( forty-two in each group ) during the subsequent two years . RESULTS In the two years after the primary dislocation , the risk of a further dislocation was reduced by 76 % and the risk of all recurrent instability was reduced by 82 % in the Bankart repair group compared with the group that had arthroscopy and lavage alone . The functional scores were also better ( p < 0.05 ) , the treatment costs were lower ( p = 0.012 ) , and patient satisfaction was higher ( p < 0.001 ) after arthroscopic repair . The improved functional outcome appeared to be mediated through the prevention of instability since the functional outcome in patients with stable shoulders was similar , irrespective of the initial treatment allocation . The patients who had a Bankart repair and played contact sports were also more likely to have returned to their sport at two years ( relative risk = 3.4 , p = 0.007 ) . CONCLUSIONS Following a first-time anterior dislocation of the shoulder , there is a marked treatment benefit from primary arthroscopic repair of a Bankart lesion , which is distinct from the so-called background therapeutic effect of the arthroscopic examination and lavage of the joint . However , primary repair does not appear to confer a functional benefit to patients with a stable shoulder at two years after the dislocation Background Nonoperative treatment of traumatic shoulder dislocations leads to a high rate of recurrent dislocations . Hypothesis Early arthroscopic treatment for shoulder dislocation will result in a lower recurrence rate than nonoperative treatment . Study Design Prospect i ve , r and omized clinical trial . Methods Two groups of patients were studied to compare nonoperative treatment with arthroscopic Bankart repair for acute , traumatic shoulder dislocations in young athletes . Fourteen nonoperatively treated patients underwent 4 weeks of immobilization followed by a supervised rehabilitation program . Ten operatively treated patients underwent arthroscopic Bankart repair with a bioabsorbable tack followed by the same rehabilitation protocol as the nonoperatively treated patients . The average follow-up was 36 months . Results Three patients were lost to follow-up . Twelve nonoperatively treated patients remained for follow-up . Nine of these ( 75 % ) developed recurrent instability . Six of the nine have required subsequent open Bankart repair for recurrent instability . Of the nine operatively treated patients available for follow-up , only one ( 11.1 % ) developed recurrent instability . Conclusions Arthroscopic stabilization of traumatic , first-time anterior shoulder dislocations is an effective and safe treatment that significantly reduces the recurrence rate of shoulder dislocations in young athletes when compared with conventional , nonoperative treatment BACKGROUND An initial anterior dislocation of the shoulder becomes recurrent in 66 % to 94 % of young patients after immobilization of the shoulder in internal rotation .  Magnetic resonance imaging and studies of cadavera have shown that coaptation of the Bankart lesion is better with the arm in external rotation than it is with the arm in internal rotation . Our aim was to determine the benefit of immobilization in external rotation in a r and omized controlled trial . METHODS One hundred and ninety-eight patients with an initial anterior dislocation of the shoulder were r and omly assigned to be treated with  immobilization in either internal rotation ( ninety-four shoulders ) or external rotation  ( 104 shoulders ) for three weeks . The primary outcome measure was a recurrent dislocation or subluxation . The minimum follow-up period was two years . RESULTS The follow-up rate was seventy-four ( 79 % ) of ninety-four in the internal rotation group and eighty-five ( 82 % ) of 104 in the external rotation group . The compliance rate was thirty-nine ( 53 % ) of seventy-four in the internal rotation group and sixty-one ( 72 % ) of eighty-five in the external rotation group ( p = 0.013 ) . The intention-to-treat analysis revealed that the recurrence rate in the external rotation group ( twenty-two of eighty-five ; 26 % ) was significantly lower than that in the internal rotation group ( thirty-one of seventy-four ; 42 % ) ( p = 0.033 ) with a relative risk reduction of 38.2 % . In the subgroup of patients who were thirty years of age or younger , the relative risk reduction was 46.1 % . CONCLUSIONS Immobilization in external rotation after an initial shoulder dislocation reduces the risk of recurrence compared with that associated with the conventional method of immobilization in internal rotation . This treatment method appears to be particularly beneficial for patients who are thirty years of age or younger BACKGROUND During 1978 and 1979 , we initiated a prospect i ve multicenter study to evaluate the results of nonoperative treatment of primary anterior shoulder dislocation . In the current report , we present the outcome after twenty-five years . METHODS Two hundred and fifty-five patients ( 257 shoulders ) with an age of twelve to forty years who had a primary anterior shoulder dislocation were managed with immobilization ( achieved by tying the arm to the torso with use of a b and age ) or without immobilization .  All 227 living patients ( 229 shoulders ) completed the follow-up question naire , and 214 patients completed the Disabilities of the Arm , Shoulder and H and ( DASH ) question naire . RESULTS Ninety-nine ( 43 % ) of 229 shoulders had not redislocated , and seventeen ( 7 % ) redislocated once . Thirty-three recurrent dislocations had become stable over time ( 14.4 % ) , and eighteen were considered to be still recurrent ( 7.9 % ) . Sixty-two shoulders ( 27 % ) had undergone surgery for the treatment of recurrent instability . Immobilization after the primary dislocation did not change the prognosis . Only two of twenty-four shoulders with a fracture of the greater tuberosity at the time of the primary dislocation redislocated ( p < 0.001 ) . When shoulders with a fracture of the greater tuberosity were excluded , forty-four ( 38 % ) of 115 shoulders in patients who had been twelve to twenty-five years of age at the time of the original dislocation and sixteen ( 18 % ) of ninety shoulders in patients who had been twenty-six to forty years of age had undergone surgical stabilization . At twenty-five years , fourteen ( 23 % ) of sixty-two shoulders that had undergone surgical stabilization were in patients who subsequently had a contralateral dislocation , compared with seven ( 7 % ) of ninety-nine shoulders in patients in whom the index dislocation had been classified as solitary ( p = 0.01 ) . Gender and athletic activity did not appear to affect the redislocation rate ; however , women had worse DASH scores than men did ( p = 0.006 ) . CONCLUSIONS After twenty-five years , half of the primary anterior shoulder dislocations that had been treated nonoperatively in patients with an age of twelve to twenty-five years had not recurred or had become stable over time PURPOSE To compare the results of arthroscopic repair in acute anterior shoulder traumatic dislocation with those of nonoperative treatment . TYPE OF STUDY A prospect i ve nonr and omized study was performed . METHODS Between August 1989 and April 1997 , 46 patients were seen after a first episode of traumatic anterior shoulder dislocation . The average age was 21 years ( range , 17 to 27 years ) . Most dislocations were in rugby players ( 36 patients ) . There were 18 patients treated by nonoperative methods and 28 patients treated by acute arthroscopic repair ; 22 patients using transglenoid suture and 6 patients with bone anchor suture fixation . RESULTS Of the patients treated nonoperatively , 94.5 % suffered a redislocation between 4 and 18 months ( average , 6 months ) . In the operative group , 96 % of the patients ( 27 ) obtained excellent results according to the Rowe scale . Only 1 patient suffered a redislocation 1 year after surgery . Three different types of lesions were found during surgery : group I , capsular tear with no labrum lesion ( 4 % ) ; group II , capsular tear with partial labrum detachment ( 32 % ) ; and group III , capsular tear and full anterior labrum detachment ( 64 % ) . The average follow-up was 67.4 months ( range , 28 to 120 ) . There were no surgical complications . CONCLUSIONS The operative group obtained 96 % excellent results , but the nonoperative group only obtained 5.5 % excellent results , according to the Rowe scale . The nonoperative group showed a high incidence of redislocation ( 94.5 % ) compared with the operative group ( 4 % ) . Based on the findings of this study , we recommend using an arthroscopic evaluation and repair after an initial anterior traumatic shoulder dislocation in young athletes A prospect i ve study evaluating nonoperative treatment versus arthroscopic Bankart suture repair for acute , ini tial dislocation of the shoulder was undertaken in young athletes . All patients met the following criteria : 1 ) sus tained an acute first-time traumatic anterior dislocation , 2 ) no history of impingement or occult subluxation , 3 ) the dislocation required a manual reduction , and 4 ) no concomitant neurologic injury . Thirty-six athletes ( average age , 20 years ) met the criteria for inclusion . Group I patients were immobilized for 1 month followed by rehabilitation ; they were allowed full activity at 4 months . Group II patients underwent arthroscopic Bankart repair followed by the same protocol as Group I. Group I consisted of 15 athletes . Twelve patients ( 80 % ) developed recurrent instability ; 7 of the 12 have required open Bankart repair for recurrent instability . Group I consisted of 21 patients ; 18 patients ( 86 % ) had no recurrent instability at last followup ( average , 32 months ; range , 15 to 45 ) ( P = 0.001 ) . One patient in Group II has required a subsequent open Bankart repair to treat symptomatic recurrence ( P = 0 
    Output:
    
Arthroscopic stabilization  was the preferred strategy after a primary anterior glenohumeral dislocation .
In clinical setting s where the likelihood of recurrent instability is low after nonoperative care or when an informed patient has an aversion to surgery , nonoperative treatment may be the preferred treatment strategy