***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 
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    Input: OBJECTIVE To evaluate displacement of the coracoacromial ligament ( CAL ) , using dynamic ultrasonography ( US ) , for detecting instability-related impingement caused by overhead activities . DESIGN Between-group survey . SETTING Department of Physical Medicine and Rehabilitation in a tertiary care center . PARTICIPANTS Volunteer high school volleyball players with unilateral shoulder pain ( n=10 ) and volunteer asymptomatic high school volleyball players with identical training activities as control subjects ( n=16 ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURE The displacement of the CAL was measured during throwing simulation using dynamic US . Both shoulders of all subjects were evaluated . RESULTS During throwing simulation , the displacement of the CAL in the painful shoulders of overhead athletes increased significantly greater than the displacement in the asymptomatic shoulder ( 3.0+/-0.7 mm and 2.2+/-0.4 mm , respectively ; P=.017 ) . No difference was identified between the displacements of the CALs of bilateral shoulders of the control group subjects . CONCLUSIONS Dynamic US , by measuring the displacement of the CAL during simulation of throwing , may be helpful in detecting abnormal humeral head upward migration in overhead athletes BACKGROUND The purpose of this prospect i ve study was to report the long-term risks of rotator cuff tear enlargement and symptom progression associated with degenerative asymptomatic tears . METHODS Subjects with an asymptomatic rotator cuff tear in one shoulder and pain due to rotator cuff disease in the contralateral shoulder enrolled as part of a prospect i ve longitudinal study . Two hundred and twenty-four subjects ( 118 initial full-thickness tears , fifty-six initial partial-thickness tears , and fifty controls ) were followed for a median of 5.1 years . Vali date d functional shoulder scores were calculated ( visual analog pain scale , American Shoulder and Elbow Surgeons [ ASES ] , and simple shoulder test [ SST ] scores ) . Subjects were followed annually with shoulder ultrasonography and clinical evaluations . RESULTS Tear enlargement was seen in 49 % of the shoulders , and the median time to enlargement was 2.8 years . The occurrence of tear-enlargement events was influenced by the severity of the final tear type , with enlargement of 61 % of the full-thickness tears , 44 % of the partial-thickness tears , and 14 % of the controls ( p < 0.05 ) . Subject age and sex were not related to tear enlargement . One hundred subjects ( 46 % ) developed new pain . The final tear type was associated with a greater risk of pain development , with the new pain developing in 28 % of the controls , 46 % of the shoulders with a partial-thickness tear , and 50 % of those with a full-thickness tear ( p < 0.05 ) . The presence of tear enlargement was associated with the onset of new pain ( p < 0.05 ) . Progressive degenerative changes of the supraspinatus muscle were associated with tear enlargement , with supraspinatus muscle degeneration increasing in 4 % of the shoulders with a stable tear compared with 30 % of the shoulders with tear enlargement ( p < 0.05 ) . Nine percent of the shoulders with a stable tear showed increased infraspinatus muscle degeneration compared with 28 % of those in which the tear had enlarged ( p = 0.07 ) . CONCLUSIONS This study demonstrates the progressive nature of degenerative rotator cuff disease . The risk of tear enlargement and progression of muscle degeneration is greater for shoulders with a full-thickness tear , and tear enlargement is associated with a greater risk of pain development across all tear types . LEVEL OF EVIDENCE Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence BACKGROUND Many studies have attempted to correlate radiographic acromial characteristics with rotator cuff tears , but the results have not been conclusive . Therefore , the purpose of this study was to determine the relationship between rotator cuff disease and the development of symptoms with different radiographic acromial characteristics , including shape , index , and presence of a spur . MATERIAL S AND METHODS The records of 216 patients enrolled in an ongoing prospect i ve , longitudinal study investigating asymptomatic rotator cuff tears were review ed . All patients underwent st and ardized radiographic evaluation , clinical evaluation , and shoulder ultrasonography at regularly scheduled surveillance visits . Three blinded observers review ed all radiographs to determine the acromial morphology , presence , and size of an acromial spur , as well as the acromial index . These findings were analyzed to determine an association with the presence of a full-thickness rotator cuff tear . RESULTS The 3 observers demonstrated poor agreement for acromial morphology ( κ = 0.41 ) , substantial agreement for the presence of an acromial spur ( κ = 0.65 ) , and excellent agreement for the acromial index ( κ = 0.86 ) . The presence of an acromial spur was highly associated with the presence of a full-thickness rotator cuff tear ( P = .003 ) , even after adjusting for age . No association was found between the acromial index and rotator cuff disease ( P = .92 ) . CONCLUSION The presence of an acromial spur is highly associated with the presence of a full-thickness rotator cuff tear in symptomatic and asymptomatic patients . The acromial morphology classification system is an unreliable method to assess the acromion . The acromial index shows no association with the presence of rotator cuff disease Objective To determine if focal increased uptake at the rotator interval ( RI ) and /or inferior capsule ( IC ) on18F-FDG PET/CT ( “ positive PET ” ) predicts the presence of adhesive capsulitis ( AC ) . Material s and methods Three population s were retrospectively examined . Group 1 included 1,137 consecutive 18F-FDG PET/CT studies  and was used to determine the prevalence of focal uptake at the RI or IC . Group 2 included 361 cases from a 10-year period with 18F-FDG PET/CT and MRI of shoulder performed within 45 days of each other and was used to enrich the study group . Group 3 included 109 r and omly selected patients from the same time frame as groups 1 and 2 and was used to generate the control group . The study group consisted of 15 cases from the three groups , which had positive PET findings . PET/CT images were assessed in consensus by two musculoskeletal radiologists . The reference st and ard for a diagnosis of AC was clinical and was made by review of the medical record by a pain medicine physician . Results The prevalence of focal activity at either the RI or IC ( “ positive PET ” ) was 0.53 % . Nine patients had a clinical diagnosis of AC and 15 patients had a positive PET . The sensitivity and specificity of PET  for detection of AC was 56 % and 87 % , respectively . PET/CT had a positive likelihood ratio for AC of 6.3 ( 95 % CI : 2.8–14.6 ) . Conclusions Increased uptake at the RI or IC on PET/CT confers a moderate increase in the likelihood of AC Background : Some patients with rotator cuff tears complain of pain , whereas others are asymptomatic . Previous studies have pointed out the presence of active bone metabolism in the painful shoulder , identified with increased radioisotope uptake during bone scintigraphy . Hypothesis : Shoulders with symptomatic rotator cuff tears will demonstrate higher radioisotope uptake than shoulders with asymptomatic tears with bone scintigraphy , reflecting active bone metabolism in symptomatic tears . Study Design : Cross-sectional study ; Level of evidence , 3 . Methods : The study consisted of 3 groups : patients with symptomatic tears ( symptomatic group ) , patients with asymptomatic tears ( asymptomatic group ) , and controls ( no tear group ) . The symptomatic group consisted of 28 shoulders from 28 patients with symptomatic rotator cuff tears ( pain score ≤4 on the University of California , Los Angeles [ UCLA ] shoulder evaluation form ) who underwent bone scintigraphy followed by rotator cuff repair .  Of 70 volunteers who had previously undergone bone scintigraphy for diseases unrelated to their shoulder , 34 were selected for the asymptomatic group ( pain score ≥8 on the UCLA shoulder form ) , and 32 were selected for the no tear group . Results : The mean radioisotope uptake in the symptomatic group was significantly higher than that in the asymptomatic group ( P = .02 ) and the no tear group ( P = .02 ) . Ten of 28 shoulders ( 36 % ) in the symptomatic group showed increased radioisotope uptake exceeding 2 st and ard deviations from the mean of the no tear group . This percentage was significantly higher when compared with the asymptomatic group ( 0 % ) ( P < .01 ) . Conclusion : Shoulders with a symptomatic rotator cuff tear showed higher radioisotope uptake on bone scintigraphy than those with an asymptomatic tear . The radioisotope uptake in shoulders with an asymptomatic tear was comparable with that in shoulders without a tear . Clinical Relevance : Positive radioisotope uptake may be associated with pain in a subgroup of patients with rotator cuff tears Subacromial impingement is one of the most common causes of painful shoulder in the middle aged and elderly population . Since Neer ’s first description of the process , many investigators have research ed this condition in an effort to gain a better underst and ing of the disease etiology . The aim of this study was to investigate the relationship between the  radiological subacromial distance measurements  and the subacromial impingement syndrome in a series of patients from our institution . For this purpose , 44 patients scheduled for a unilateral shoulder arthroscopy were investigated prospect ively . The acromio-glenoid angle , supraspinatus-glenoid angle ( from coronal MR images ) and acromial index ( from true anterior-posterior shoulder X-ray images ) were measured as the implication s of the subacromial distance , and the degree of subacromial impingement was grade d according to intraoperative findings . Statistical data analysis revealed no significant correlations between the radiological measurements and the severity of subacromial impingement ( p > 0.05 ) . On the other h and , there was a significant correlation ( p = 0.0049 ) between the patient age and subacromial impingement . These results suggest that the radiological subacromial distance measurements do not have enough clinical significance as predictive markers in the subacromial impingement syndrome Background Ultrasound is increasingly used to evaluate shoulder pain , but the benefits of this are unclear . In this study , we examined whether ultrasound-defined pathologies have implication s for clinical outcomes . Methods We extracted reported pathologies from 3000 ultrasound scans of people with shoulder pain referred from primary care . In latent class analysis ( LCA ) , we identified whether individual pathologies clustered in groups . Optimal group number was determined by the minimum Bayesian information criterion . A question naire was sent to all patients scanned over a 12-month period ( n = 2322 ) . Data collected included demographics , treatments received , current pain and function . The relationship between pathology-defined groups and clinical outcomes was examined . Results LCA revealed four groups : ( 1 ) bursitis with limited inflammation elsewhere ( n = 1280 ) , ( 2 ) bursitis with extensive inflammation ( n = 595 ) , ( 3 ) rotator cuff tears ( n = 558 ) and ( 4 ) limited pathology ( n = 567 ) . A total of 777 subjects ( 33 % ) completed question naires . The median ( IQR ) duration post-ultrasound scan was 25 ( 22–29 ) months . Subsequent injections were most common in groups 1 and 2 ( groups 1–4 76 % , 67 % , 48 % and 61 % , respectively ) ; surgery was most common in group 3 ( groups 1–4 23 % , 21 % , 28 % and 16 % , respectively ) . Shoulder Pain and Disability Index scores were highest in group 3 ( median 48 and 30 , respectively ) and lowest in group 4 ( median 32 and 9 , respectively ) . Patients in group 4 who had surgery reported poor outcomes . Conclusions In a community-based population , we identified clusters of pathologies on the basis of ultrasound . Our retrospective data suggest that these groups have different treatment pathways and outcomes . This requires replication in a prospect i ve study to determine the value of a pathology-based classification in people with shoulder pain OBJECTIVES Rotator cuff tendinopathy is a common source of shoulder pain characterised by persistent and /or recurrent problems for a proportion of sufferers . The aim of this study was to pilot the methods proposed to conduct a substantive study to evaluate the effectiveness of a self-managed loaded exercise programme versus usual physiotherapy treatment for rotator cuff tendinopathy . DESIGN A single-centre pragmatic unblinded parallel group pilot r and omised controlled trial . SETTING One private physiotherapy clinic , northern Engl and . PARTICIPANTS Twenty-four participants with rotator cuff tendinopathy . INTERVENTIONS The intervention was a programme of self-managed loaded exercise . The control group received usual physiotherapy treatment . MAIN OUTCOMES Baseline assessment comprised the Shoulder Pain and Disability Index ( SPADI ) and the Short-Form 36 , repeated three months post r and omisation . RESULTS The recruitment target was met and the majority of participants ( 98 % ) were willing to be r and omised . 100 % retention was attained with all participants completing the SPADI at three months . Exercise adherence rates were 
    Output:
    
There was no significant association between most imaging features and symptoms among high- quality , cross-sectional studies .
There was low- quality evidence that enhancement of the joint capsule on MRI and increased uptake on PET were associated with symptoms in adhesive capsulitis .
Based on high- quality longitudinal studies , enlarging rotator cuff tears were associated with an increased incidence of symptoms .
There were conflicting results on the association of imaging features with shoulder symptoms and their persistence .