Influence of adducting and abducting muscle forces on the subacromial space width

PURPOSE: Strengthening of the shoulder depressors is an important component in the treatment of impingement syndrome. However, the quantitative effect of various muscle forces on the width of the subacromial space has never been demonstrated in vivo. Therefore, the purpose of this study was to analyze the influence of adducting and abducting muscle forces on the subacromial space width in healthy volunteers in various arm positions. METHODS: The shoulders of 12 healthy volunteers were imaged with an open MR system at 30 degrees, 60 degrees, 90 degrees, 120 degrees, and 150 degrees of arm elevation under both isometric adducting and abducting muscle activity (15 N). After segmentation and three-dimensional reconstruction of anatomically relevant structures, the minimal spatial acromiohumeral and claviculohumeral distances were quantified. RESULTS: Adducting muscle forces led to a significant increase of the acromiohumeral distance in all arm positions (P < 0.01), varying from 32% (30 degrees ) to 138% (90 degrees ) relative to abducting muscle forces. The claviculohumeral distance showed an increase of 9% (30 degrees ) to 24% (90 degrees ), this increase being also statistically significant at all positions (P < 0.05). During elevation of the arm (30-120 degrees ), the absolute subacromial space width was reduced significantly (P = 0.001) by 30% under isometric contraction of the adductors compared with 53% (P = 0.001) under activation of the abductors. CONCLUSION: This in vivo study shows for the first time that adducting muscle forces lead to a significant increase of the subacromial space width compared with abducting muscle activity. In the future, this technique and data can be used to objectively quantify the effect of physical therapy protocols focused on increasing the depressor effect of adducting muscles in the postoperative and conservative treatment of impingement syndrome of the shoulder.     

Acromiohumeral distance in a seated position in persons with impingement syndrome

PURPOSE: To compare the acromiohumeral distance (AHD) of both shoulders in subjects with a unilateral shoulder impingement syndrome (SIS) and healthy subjects in a seated position during free shoulder movements of large amplitude. MATERIALS AND METHODS: Using a 0.5-Tesla SIGNA-SP/i trade mark open-configuration magnetic resonance imaging (MRI) system, the AHD was measured at several arm positions, in a standardized seated position. RESULTS: In flexion (rest to 130 degrees ), the mean AHD of SIS varied from 8.3 to 2.8 mm, as compared to from 8.7 to 4.1 mm for asymptomatic contralateral shoulders. In abduction (rest to 110 degrees ), the AHD varied from 8.1 to 3.4 mm and from 8.8 to 4.6 mm for SIS and asymptomatic shoulders, respectively. The smallest AHD (P <.01) was observed at 110 degrees. From 80 degrees of arm elevation, the AHD was significantly smaller in impingement than in asymptomatic shoulders (P <.05). The AHD of asymptomatic shoulders did not differ from that of healthy subjects. In SIS, the AHD at rest was correlated with its reduction at all shoulder positions (r(p) = 0.62-0.88), but was a poor predictor of the smallest AHD observed at 110 degrees (flexion, R(2) = 0.09; abduction, R(2) = 0.08). CONCLUSION: In the critical arm elevation positions for impingement, AHD is discriminative for SIS, compared to asymptomatic shoulders and healthy ones. AHD at rest is a good indicator of the magnitude of its reduction in elevation, but not of the smallest AHD in arm elevation.     

A technique for determining the spatial relationship between the rotator cuff and the subacromial space in arm abduction using MRI and 3D image processing

An MR imaging-based technique for three-dimensional determination of subacromial space width in relation to the rotator cuff in arm abduction is presented. Five volunteers were examined in an open MRI in seven arm positions, and coronal images were obtained with a gradient-echo sequence. 30 reconstruction of the bones and the supraspinatus was performed, and the minimal spatial distances between acromion, clavicle, and humerus were calculated. The closest contact between the supraspinatus and the anterior ioferior part of the acromion occurred at 90° abduction in internal rotation. The technique presented allows investigation of the morphological basis of the impingement syndrome.     

肩关节冈上肌出口位X线摄影在肩峰下撞击综合征中的应用价值

目的:探讨肩关节冈上肌出口位X线摄影所示肩峰形态、肩峰下间隙与肩峰下撞击综合征(shoulder impingement syndrome,SIS)的相关性,总结其临床应用价值。方法:回顾性分析60例经临床证实的SIS患者的临床及影像资料,对X线摄影所示的肩峰形态及肩峰下间隙进行分型、测量,并与MRI所见进行对照,分析肩峰形态及肩峰下间隙与SIS的相关性。结果:60例患者中,肩峰平坦形(Ⅰ型)8例、弧形(Ⅱ型)10例、钩状(Ⅲ型)42例。冈上肌出口位X线摄影所示肩峰下间隙为(1.21±0.36)cm,MRI所示肩峰下间隙值为(1.10±0.18)cm,两者差异无统计学意义(P0.05)。肩袖损伤MRI分级Ⅰ级27例,Ⅱ级20例,Ⅲ级13例。肩峰下间隙值与肩袖损伤MRI分级呈正相关(P0.05)。结论:肩关节冈上肌出口位X线摄影所示肩峰形态、肩峰下间隙与SIS发生密切相关;当肩峰形态为钩状及肩峰下间隙值1cm,强烈提示SIS可能,对于无MRI的基层医院诊断SIS临床意义明显,值得临床应用。     

Dynamic ultrasound of the subacromial–subdeltoid bursa in patients with shoulder impingement: a comparison with normal volunteers

Objective

The purpose of the study was to determine if the thickness of the subacromial–subdeltoid (SASD) bursa during dynamic ultrasound and on static views differs between patients with shoulder impingement syndrome and healthy volunteers.

Materials and methods

Twenty-two patients with a clinical diagnosis of shoulder impingement syndrome and 23 healthy volunteers were recruited. A subset of patients showing an immediate symptom response following intrabursal injection was identified as “injection responders”. Ultrasound of the shoulder was performed on all participants using three standard static views and two dynamic views (before and after arm abduction). The thickness of both the intrabursal fluid and the superficial peribursal fat was measured on all views. The bursal thickness measurements in the two groups were compared using a t test for significance.

Results

The mean increase in SASD bursal fluid thickness following arm abduction was not statistically different among all patients (0.39?±?0.41?mm) and controls (0.35?±?0.32?mm), p?=?0.72. The same was true comparing injection responders (0.46?±?0.49?mm) with controls, p?=?0.41. On static views, greater bursal fluid thickness was found in patients (1.01?±?0.48?mm) compared with controls (0.67?±?0.32?mm) when using the short axis view of the supraspinatus, p?=?0.006. No statistically significant difference was found between injection responders and controls when measuring peribursal fat thickness on any view.

Conclusions

Gathering of the SASD bursa demonstrated during dynamic ultrasound does not necessarily indicate painful impingement of the bursa as it is found to a similar degree in patients with a clinical diagnosis of impingement and healthy volunteers.     

Ultrasound measurement of rotator cuff thickness and acromio-humeral distance in the diagnosis of subacromial impingement syndrome of the shoulder

The usefulness of ultrasound measurements in the diagnosis of the subacromial impingement syndrome of the shoulder was evaluated. Fifty-seven patients with unilateral symptoms of the impingement syndrome underwent ultrasound examination of both shoulder joints, which included assessment of rotator cuff integrity, measurement of rotator cuff thickness and the distance between the infero-lateral edge of acromion and the apex of the greater tuberosity of humerus (AGT distance) in the standard ultrasonographic positions. As a control group, 36 volunteers (72 shoulders) with no history of shoulder pain were examined sonographically. Ultrasonographic assessment of humeral head elevation, measured as the AGT distance, proved to be useful in establishing the diagnosis of the subacromial impingement syndrome of the shoulder. A difference in rotator cuff thickness of more than 1.1 mm and a difference in the AGT distance of more than 2.1 mm between both shoulder joints may reflect dysfunction of rotator cuff muscles.     

MR study of the intrinsic acromial angle in 74 symptomatic patients

PURPOSE: The study was undertaken to define some measurements on sagittal MR images that could provide quantitative data on the subacromial space in patients affected by nonspecific impingement syndrome and to correlate these measurements with the Bigliani classification of acromial morphology. MATERIALS AND METHODS: We retrospectively reviewed 74 shoulders in 74 patients (47 males, 27 females, age range 35-62 years) who presented with mechanical disability and pain. The patients underwent MRI using T1-weighted sagittal oblique and coronal SE sequences (TR 500 ms ,TE 12 ms) and T2-weighted FSE sequences (TR 3500, TE 25 ms) with dedicated coil. Two parameters were evaluated: the intrinsec acromial angle and the acromio-humeral distance. The measurements were made on the sagittal images at the acromion-clavicular junction and correlated to the Bigliani classification of acromial morphology. The images were evaluated by two radiologists blinded to the patients' identity, history and arthroscopic results. RESULTS: The acromial angle was measured in 72 shoulders. The values were found to correlate with the Bigliani classification. In our series, the intrinsic acromial angle (resulting from the intersection between the longitudinal acromial axis and the tangent to the acromial undersurface) ranged from 0 degrees to 17 degrees. In shoulders with rotator cuff tears the acromial angle varied between 8 degrees and 17 degrees. There were no tears for acromial angles below 8 degrees, whereas in patients with full-thickness tears the angles ranged from a minimum of 12 degrees to a maximum of 15 degrees. Acromio-humeral distance ranged from 2 mm to 10 mm; in patients with cuff tears it could not be assessed as it was close to zero in nearly all cases, whereas in cases of impingement without cuff tear it ranged from 5 mm to 10 mm. Impingement without cuff tear was detected in 31 cases, with angles ranging from 10 degrees to 17 degrees. CONCLUSIONS: Our findings demonstrate the effectiveness of the two quantitative parameters (intrinsic acromial angle and acromio-humeral distance) which are important causative factors in impingement syndrome. These parameters were found to be consistent and comparable with the Bigliani classification of acromial morphology which, although providing useful qualitative data, does not fully respond to our quantitative needs. Our study suggests that impingement syndrome is negatively correlated to acromio-humeral distance and positively correlated to intrinsic acromial angle. These parameters, which are readily detected with MRI, may be used by the radiologist and orthopaedic surgeon to screen patients with nonspecific impingement syndrome.     

The shoulder impingement syndrome: prevalence of radiographic findings and correlation with response to therapy

The shoulder impingement syndrome is believed to be caused by compression of the rotator cuff tendons and subacromial bursa between the humeral head and structures that make up the coracoacromial arch. Plain film findings were tabulated for 36 patients, 22-81 years old, who had signs and symptoms of an acute impingement syndrome. The most common radiographic abnormalities were subacromial bony proliferation in 68%, degenerative changes in the greater tuberosity of the humerus in 66%, and degenerative joint disease in the acromioclavicular joint in 66%. There was evidence of calcium deposition in the rotator cuff in 37%, inferiorly oriented acromioclavicular osteophytes in 32%, and degenerative changes of the lesser humeral tuberosity in 29%. The acromiohumeral space was narrowed in only 21%. The radiographic findings were scored blindly and compared to the treatment outcome of 6 weeks of medical therapy. There was no statistically significant correlation between any of the radiographic findings and the response to medical therapy. The results suggest that radiographic findings are extremely common in patients with the acute impingement syndrome, but that they are not useful as prognostic indicators of the short-term response to medical treatment.     

Acromio-humeral distance variation measured by ultrasonography and its association with the outcome of rehabilitation for shoulder impingement syndrome.

OBJECTIVE: First, to validate an ultrasonographic measure of the acromio-humeral distance (AHD); second, to compare the AHD variation during active abduction in patients with shoulder impingement syndrome (SIS) and healthy subjects; and third, to evaluate the relationship between functional status and AHD variations before and after rehabilitation in SIS subjects. DESIGN: This study has 3 components: (1) a reliability study, (2) a case-control study, and (3) a preliminary pretreatment/posttreatment clinical trial. SETTING: Primary care hospital setting. PARTICIPANTS: Seven SIS patients and 13 healthy subjects. INTERVENTIONS: For the clinical trial, the SIS subjects participated in 12 sessions of a rehabilitation program over 4 weeks. MAIN OUTCOME MEASURES: First, intraclass correlation coefficient for interobserver reliability; second, AHD measured at 0 degrees, 45 degrees, and 60 degrees of active abduction; and third, Western Ontario Rotator Cuff Index. RESULTS: Intraclass correlation coefficient for interobserver reliability ranged from 0.86 to 0.92 for the 3 shoulder positions. A significant reduction of the AHD was found within groups between rest and active abduction (P < 0.05). Comparison of AHD between groups was not statistically different (P = 0.06; beta < 0.80). In pre-post rehabilitation analysis, improvement of the Western Ontario Rotator Cuff Index score was positively correlated to the reduction of the AHD narrowing as the arm was abducted (r = 0.86; P = 0.01). CONCLUSIONS: The ultrasound measure of AHD is reliable and sensitive. Although a distinct pattern of AHD variation in SIS patients could not be confirmed, a strong positive relationship was found between the reduction of AHD narrowing and functional improvement following rehabilitation. Ultrasound measurement of AHD might help identify SIS patients who will benefit from rehabilitation.     

Thoracic outlet: assessment with MR imaging in asymptomatic and symptomatic populations

PURPOSE: To compare the dynamic modifications of the thoracic outlet in asymptomatic volunteers and symptomatic patients and assess the presence and location of vasculonervous compressions in these two populations. MATERIALS AND METHODS: Thirty-five healthy volunteers and 54 patients with clinical symptoms of thoracic outlet syndrome (TOS) underwent magnetic resonance (MR) imaging of the thoracic outlets with their arms alongside their bodies and after a postural maneuver. Measurements were obtained at the interscalene triangle (thickness of anterior scalene muscle, interscalene angle), at the costoclavicular space (minimum costoclavicular distance, distance between inferior border of subclavius muscle and the anterior chest wall, maximum thickness of subclavius muscle, angle between first rib shaft and horizontal), and at the retropectoralis minor space (distance between posterior border of pectoralis minor muscle and posterior lining of axilla at the passage of the axillary vessels, thickness of pectoralis minor muscle). The presence and location of vasculonervous compressions were also assessed. Group data were analyzed with the Student t test. RESULTS: Patients with TOS had a smaller costoclavicular distance after the postural maneuver (P <.001), a thicker subclavius muscle in both arm positions (P <.001), and a wider retropectoralis minor space after the postural maneuver (P <.001) than did volunteers. Venous compressions after the postural maneuver were observed in 47% of volunteers and 63% of patients at the prescalene space, in 54% of volunteers and 61% of patients at the costoclavicular space, and in 27% of volunteers and 30% of patients at the retropectoralis minor space. Arterial and nervous compressions, respectively, were seen in 72% and 7% of patients. No arterial or nervous compression was seen in volunteers. Except for venous thrombosis, vasculonervous compressions were demonstrated only with arm elevation. Only three thoracic outlet measurements differed significantly in both populations. CONCLUSION: MR imaging appeared helpful in demonstrating the location and cause of arterial or nervous compressions.     

Supraspinatus tendon US morphology in basketball players: correlation with main pathologic models of secondary impingement syndrome in young overhead athletes. Preliminary report

PURPOSE: The purpose of this study was to investigate supraspinatus tendon sonographic morphology in a population of young overhead athletes in correlation with main pathologic models of secondary shoulder impingement syndrome. SUBJECTS AND METHODS: Between April and May 2004, 20 subjects (ten professional basketball players and ten non-athlete controls of the same age, weight and height ranges) underwent bilateral, standardised, sonographic sholulder examination to evaluate supraspinatus echotexture, supraspinatus and subacromial bursa thickness, subacromial space width (cutoff of 7 mm) and dynamic anterior impingement beneath the acromial margin. RESULTS: All subjects were right handed. No symptomatic controls were found. Four players showed signs and symptoms of right atraumatic shoulder instability (two cases) or supraspinatus impingement with anterior pain (one right and one left shoulder). Subacromial space width was reduced in five right-dominant players' shoulders (three symptomatic and two asymptomatic) versus zero controls (p<0.05) and in eight players' shoulders versus zero controls on total shoulders (p<0.05). No other significant differences were observed between the two groups in sonographic parameters considered. CONCLUSIONS: Despite the study limitations, ultrasonography (US) is able to detect subacromial space narrowing in young overhead athletes as early shoulder impingement sign, according to the continuum impingement-instability pathologic model.     

Impingement of the rotator cuff in athletes caused by instability of the shoulder joint

An impingement of the rotator cuff can be caused by chronic anterior instability of the shoulder joint. This particular disease is often found in athletes engaged in overhead motion in abduction/external rotation of the arm, such as in ball sports like volleyball or European handball, racket sports like tennis or badminton, or swimming. For those patients that cannot be cured by conservative treatment such as muscular stabilization, surgical treatment is indicated: anterior reconstruction of the capsule and/or the glenoid labrum, and in addition — if necessary — subacromial decompression and revision of the rotator cuff. Between October 1988 and April 1992, we operated on 66 shoulders in 64 top athletes suffering from chronic anterior or multidirectional instability of the shoulder joint that had caused an impingement syndrome of the rotator cuff. In all cases, the athlete was unaware of the instability. Conservative treatment had been unsuccessful. Surgical treatment was successful in close to 90% of the athletes.     

MR evaluation of factors predicting the development of rotator cuff tears

PURPOSE: The purpose of this work was to assess the incidence of various factors predicting impingement in the shoulder. METHOD: MR examination was used to assess various anatomic parameters in 46 patients with clinical abnormalities of the shoulder and 40 asymptomatic volunteers. All patients had undergone surgery, showing no rotator cuff tear. RESULTS: A few of the parameters evaluated were significantly different in the two groups: The acromion was more frequently curved or hook-shaped in patients than in volunteers. The acromiohumeral distances differed (4.87 mm in patients and 6.05 mm in volunteers); so did the coracohumeral distances (7.9 mm in patients and 8.9 mm in volunteers). The shape of the acromioclavicular joint and the anterior covering of the humerus, defined on the coronal view, also differed (1.07 mm in patients and 1.49 mm in volunteers). Only the shapes of the acromioclavicular joint and of the acromion were linked with age. CONCLUSION: All these factors reflected a decrease in the acromiohumeral space, except for the anterior covering of the acromial arch, which could be due to anterior instability.     

动态超声观察脑卒中患者偏瘫侧肩关节不同运动对喙肩韧带形变的影响

 目的 观察脑卒中患者偏瘫侧肩关节病变情况,明确不同被动运动对脑卒中患者偏瘫侧肩关节喙肩韧带形变的影响,减少康复训练中肩部撞击综合征的发生。方法 选择武警浙江总队医院2019年1－11月收治的31例脑卒中偏瘫患者,对患者肩关节进行规范化超声检查,测量患侧喙肩韧带在肩关节前屈,水平后伸,0°外展时内旋、外旋,90°外展时内旋和背部内旋运动时垂直位移变化,并与健侧测量结果相比较。结果 31例脑卒中偏瘫患者中发生肩关节超声异常28例(90.32%),主要病变包括:长头腱炎症并腱鞘积液 22 例,长头腱脱位 1例;滑囊炎并滑囊积液 13 例;肩袖损伤 15例,肩关节半脱位 18 例。其中23例为多种病变并存,对侧肩关节超声异常8例(25.81%),主要病变包括长头腱鞘积液3例,肩袖损伤3例,滑囊炎并滑囊积液2例。脑卒中患者偏瘫侧肩关节喙肩韧带平均垂直位移明显大于对侧组;同一运动偏瘫侧肩关节喙肩韧带垂直位移大于对侧组;不同运动对喙肩韧带垂直位移影响不同,由大到小依次为90°外展时内旋、水平后伸、前屈、背部内旋、0°外展时内旋及外旋动作,差别有统计学意义(P<0.01)。结论 超声能显示脑卒中患者偏瘫侧肩关节病变;可观察肩关节不同运动对喙肩韧带形变的影响,进行90°外展时内旋、水平后伸等对喙肩韧带形变影响较大的运动时应谨慎。     

Rotator cuff coactivation ratios in participants with subacromial impingement syndrome

Coactivation of the rotator cuff is vital to glenohumeral joint stability by centralising the humeral head within the glenoid fossa. Yet in individuals with subacromial impingement, it is hypothesised that rotator cuff coactivation abnormalities are present that could contribute to their shoulder pain. The purpose of this study was to determine if abnormal rotator cuff coactivation and deltoid activation patterns exist in participants with subacromial impingement. Rotator cuff (supraspinatus, infraspinatus, and subscapularis) coactivation and middle deltoid activation was assessed during an elevation task. ANOVA models were used to compare muscle activation patterns in 10 participants with subacromial impingement and 10 control participants. Participants with impingement exhibited decreased rotator cuff coactivation (subscapularis–infraspinatus and supraspinatus–infraspinatus) and increased middle deltoid activation at the initiation of elevation (0–30° of humeral elevation). The participants with impingement also had higher subscapularis–infraspinatus and supraspinatus–infraspinatus coactivation above the level of the shoulder where pain is typically present (90–120° of humeral elevation). The results indicate that individuals with subacromial impingement exhibit rotator cuff muscle coactivation and deltoid activation abnormalities during humeral elevation that might contribute to the encroachment of the subacromial structures associated with subacromial impingement.     

冈上肌出口位摄片诊断肩峰下撞击综合征的价值

目的:探讨冈上肌出口位X线片在诊断肩峰下撞击综合征中的应用价值。方法:回顾性分析58例经临床证实为肩峰下撞击综合征患者的冈上肌出口位X线表现,根据Bigliani肩峰分型标准进行分型,测量肩峰-肱骨头(A-H)值。结果:58例患者中,Ⅰ型11例(18.96%),Ⅱ型21例(36.21%),Ⅲ型26例(44.83%)。肩峰下间隙狭窄27例(A-H值<1cm),肩锁关节骨质增生12例,冈上肌肌腱钙化6例。结论:冈上肌出口位摄片能够提供肩峰分型的直接依据,可观察肩峰下滑动间隙、肩峰端骨赘的存在及冈上肌肌腱的钙化,对肩峰下撞击综合征的诊断具有病因学意义,并在一定程度上为骨科医生选择治疗方案提供了重要的影像依据。     

Scapular rotation in swimmers with and without impingement syndrome: practice effects

PURPOSE: The purpose of this study was to examine the effects of a normal swim practice on the scapular kinematics of swimmers with impingement syndrome and healthy swimmers. METHODS: Twenty swimmers with no known shoulder pathology and 20 swimmers with shoulder impingement syndrome participated in this study. Shoulder strength measurements were made with a hand-held dynamometer. Static scapular upward rotation was measured with an inclinometer with the arm at rest, and at 45, 90, and 135 degrees of humeral elevation. Measurements were made pre- and postswim training. RESULTS: There were no differences in baseline measurements of kinematics between the two groups. After swimming, both groups experienced muscle fatigue as indicated by a significant reduction in force generation. Although swimming practice resulted in no significant differences in scapular kinematics for the healthy swimmers, there were significant decreases in scapular upward rotation in subjects with shoulder impingement. CONCLUSIONS: Abnormal scapular kinematics in swimmers with impingement syndrome may only be observed after an intense swim practice. The examination of swimmers immediately after swimming may provide more information regarding impingement syndrome than a typical clinical exam.     

Posterior instability of the shoulder with secondary impingement in elite golfers

BACKGROUND: Shoulder injuries in golf are related to the biomechanics of the golf swing and typically occur in the lead arm at the top of the back swing. PURPOSE: We report a newly recognized entity in a series of elite golfers: posterior glenohumeral instability associated with subacromial impingement. STUDY DESIGN: Retrospective review. METHODS: Eight elite golfers were treated between March 1991 and July 1998 for pain occurring in the nondominant, lead shoulder at the top of the back swing. Posterior instability was diagnosed in all eight patients; six of the eight also demonstrated signs of subacromial impingement. Initial treatment consisted of rehabilitation. For patients in whom rehabilitation failed, surgery was performed. RESULTS: Two patients improved with nonoperative treatment and returned to play immediately. Six patients underwent shoulder arthroscopy with posterior thermal capsulorrhaphy. Four of the six also underwent arthroscopic subacromial decompression. The six surgically treated patients returned to play at an average 4 months after surgery. At an average 4.5 years of follow-up, all eight patients were playing at their previous level of competitive play. One patient had complications that led to the need for subsequent arthroscopic subacromial decompression; she eventually returned to competitive play. CONCLUSION: Clinicians should be aware of posterior shoulder instability and the associated secondary diagnosis of rotator cuff impingement as a possible cause of shoulder pain in elite golfers.     

Effect of supervised physiotherapy versus home exercise program in patients with subacromial impingement syndrome: A systematic review and meta-analysis

ObjectiveTo determine whether supervised physiotherapy is more effective for functional improvement and pain relief than a home exercise program in subjects with subacromial impingement syndrome.DesignSystematic review and meta-analysis of randomized clinical trials.MethodsAn electronic search was performed in Medline, Central, Embase, PEDro, Lilacs, Cinahl, SPORTDiscus, and Web of Science databases. The eligibility criteria for selecting studies included randomized clinical trials that compared supervised physiotherapy versus home exercise program, in the shoulder function, pain, and range of motion in subjects older than 18 years of age with a medical diagnosis of subacromial impingement syndrome treated conservatively.ResultsSeven clinical trials met the eligibility criteria, and for the quantitative synthesis, four studies were included. The standardized mean difference for shoulder function was −0.14 points (95% CI: −1.04 to 0.76; p = 0.760), mean difference 0.21 cm (95% CI: −1.36 to 1.78; p = 0.790) for pain, and mean difference 0.62° (95% CI: −7.15 to 8.38; p = 0.880) for range of motion of flexion.ConclusionSupervised physical therapy and home-based progressive shoulder strengthening and stretching exercises for the rotator cuff and scapular muscles are equally effective in patients with subacromial impingement syndrome treated conservatively.Trial registration numberCRD42018086348.     

Activation of the trapezius muscle during varied forms of Kendall exercises

The trapezius muscle plays a crucial role in maintaining proper shoulder mechanics and is often considered a source of weakness and dysfunction in patients.ObjectivesThe purpose of this study was to investigate the activation patterns of the middle and lower trapezius during four prone horizontal abduction exercises of the glenohumeral joint (GHJ).MethodsThe muscle activation patterns of 19 female and 13 male volunteers were measured using surface EMG during horizontal arm abduction exercises commonly used in rehabilitative settings. Each subject performed 10 repetitions of horizontal abduction (ABD) at each position using only the weight of the arm. Function was assessed during shoulder horizontal abduction while positioned at: 75°, 90°, 125° and 160° of GHJ ABD. Electromyographic activity was collected during the concentric phase during each test repetition in the lower (LTRAP) and middle trapezius (MTRAP). A repeated measure ANOVA was performed followed by Bonferroni's post hoc test.ResultsThe MTRAP had significantly greater recruitment at 90° and 125°, compared to 160°. Similarly, results for the lower trapezius indicated that recruitment at 90° and 125° was significantly greater than 160°.ConclusionMost significant muscle activation for the middle and lower trapezius occurred at 90° and 125° of GHJ ABD. For the clinician, training at 90° is easy to identify, and provides maximal activation, negating the need for multiple training angles.