In vivo measurement of subacromial space width during shoulder elevation: technique and preliminary results in patients following unilateral rotator cuff repair

BACKGROUND: The shoulder's subacromial space is of significant clinical interest due to its association with rotator cuff disease. Previous studies have estimated the subacromial space width to be 2-17 mm, but no study has measured in vivo subacromial space width during shoulder motion. The purpose of this study was to measure the in vivo subacromial space width during shoulder elevation in patients following rotator cuff repair. METHODS: Biplane X-ray images were collected during shoulder elevation of 11 patients who had undergone rotator cuff repair. Glenohumeral joint motion was measured from the biplane X-ray images for each subject's repaired and asymptomatic, contralateral shoulders. The joint motion data were combined with subject-specific CT models to measure the subacromial space width during shoulder motion. FINDINGS: Subacromial space width decreased with shoulder elevation, ranging from 2.3 to 7.4 mm in the repaired shoulder and 1.2-7.1 mm in the contralateral shoulder. Subacromial space width in the repaired shoulder was only 0.5 mm less than the contralateral shoulder when averaged over 10-60 degrees of glenohumeral elevation. INTERPRETATION: The results indicate that the humerus in the repaired shoulder is positioned more cranially on the glenoid than in the contralateral shoulder. It is unclear if these subtle differences in subacromial space width are due to the surgical procedure or post-operative stiffness, or if subacromial impingement contributed to the development of the rotator cuff tear. Future research will ascertain if these results represent a transient response to the surgery or a more fundamental difference in rotator cuff function between repaired and contralateral shoulders.     

Comparison of acromiohumeral distance in symptomatic and asymptomatic patient shoulders and those of healthy controls

BackgroundThe reduction of the subacromial space has traditionally been linked to rotator cuff pathology. The contribution of this narrowing, both in the development and maintenance of rotator cuff tendinopathy, is still under debate. The objective of the present study was compare the acromiohumeral distance at 0 and 60 degrees of active shoulder abduction in scapular plane, static position, in both symptomatic and contralateral shoulders, between participants with unilateral rotator cuff related shoulder pain, and in asymptomatic participants.MethodThis was a cross-sectional observational study. Seventy-six participants with chronic shoulder pain were assessed. Forty participants without shoulder pain were also recruited to compare the acromiohumeral distance with symptomatic participants. The acromiohumeral distance was measured at 0 and 60 degrees of active shoulder abduction in all the groups by ultrasound imaging. Mean differences between symptomatic versus contralateral shoulders, and versus healthy controls, were calculated.FindingsThere were no statistical significant differences (p > .05) in the acromiohumeral distance at 0 degrees of shoulder elevation between the groups. However, significant differences were found at 60° between symptomatic and contralateral shoulder groups (0,51 mm; 95% CI: −0.90 to −0.12).InterpretationsDifferences in shoulder pain perception at 0° are not attributable to acromiohumeral distance differences. However, treatments focused on increasing AHD at 60° could be prescribed, as a significantly reduced AHD was found in symptomatic shoulders when compared with contralateral shoulders. Further research is needed to determine, not only static differences in AHD, but also dynamic differences.     

Immediate effects of kinesiotaping on acromiohumeral distance and shoulder proprioception in individuals with symptomatic rotator cuff tendinopathy

BackgroundKinesiotaping is widely used for the rehabilitation of rotator cuff tendinopathy. It has been argued to reduce symptoms and functional limitations through improvement of proprioceptive feedback. In addition, kinesiotaping has been reported to increase the subacromial space in healthy subjects. However, its effects on the acromiohumeral distance and shoulder proprioception of individuals with rotator cuff tendinopathy have not been ascertained. This study investigated the immediate effects of kinesiotaping on the acromiohumeral distance and shoulder proprioception in individuals with rotator cuff tendinopathy.MethodsTwenty-two individuals with chronic rotator cuff tendinopathy were included. The acromiohumeral distance was measured using an ultrasound scanner at rest and 60° shoulder abduction. Proprioception was measured through active joint repositioning in low- (45°–65°) and mid-amplitude (80°–100°) of shoulder flexion and abduction. A wireless inertial measurement unit system was used to quantify shoulder angles. First, measurements were taken without kinesiotaping. Thereafter, kinesiotaping was applied on the symptomatic shoulder, and the same measurements were retaken. Repeated measures ANOVAs were used for statistical analyses.FindingsKinesiotaping induced a significant increase in acromiohumeral distance at 60° abduction (∆AHD = 0.94 mm; 95%CI: 0.50–1.38, p < 0.001), exceeding the minimal detectable change (0.70 mm). No significant difference was observed in acromiohumeral distance at rest or in proprioception during active joint repositioning in both low- and mid-amplitude (p > 0.05).InterpretationKinesiotaping led to an immediate increase in acromiohumeral distance at 60° of abduction that, although it seems a minor change (↑10.5%), it may be significant for symptomatic patients, whereas it had no immediate effect on active joint repositioning.     

Rotator cuff pathology and subacromial impingement

Musculoskeletal complaints are one of the most common reasons for primary care office visits, and rotator cuff disorders are the most common source of shoulder pain. Subacromial impingement with subsequent tendinitis and bursitis is frequently found in young adult patients. Rotator cuff tears are a common cause of shoulder pain in patients over age 40. The majority of subacromial impingement and incomplete rotator cuff tears may be successfully managed with conservative treatment. This article discusses anatomic function of the glenohumeral joint and subacromial space, etiology of subacromial impingement and rotator cuff disorders, examination of the shoulder, diagnostic testing, and treatment of subacromial impingement and rotator cuff disorders in the primary care setting.     

Subacromial Motion Metrics in Painful Shoulder Impingement: A Dynamic Quantitative Ultrasonography Analysis

ObjectivesTo explore the subacromial motion metrics in patients with and without subacromial impingement syndrome (SIS) and to investigate whether the abnormality was associated with rotator cuff pathologies.DesignThis cross-sectional observational study used dynamic quantitative ultrasonography imaging for shoulder joint assessment.SettingOutpatient rehabilitation clinic.ParticipantsIndividuals with SIS on at least 1 shoulder (n=32) and asymptomatic controls (n=32) (N=64).InterventionsNot applicable.Main Outcome MeasuresFrame-by-frame, the humeral greater tuberosity against the lateral edge of the acromion was traced to obtain the minimal vertical acromiohumeral distance (AHD). The rotation angle and radius of the humerus were computed using the least-squares curve fitting method.ResultsApproximately two-thirds of the shoulders with SIS did not have any sonographically identifiable rotator cuff pathologies. There was a consistent trend of nonsignificantly increased humeral rotation angles in painful shoulders. The generalized estimating equation demonstrated that the decreased minimal vertical AHD was associated with painful subacromial impingement (β coefficient: ?0.123cm, 95% confidence interval [CI], ?0.199 to ?0.047). The area under the curve for the minimal vertical AHD to discriminate painful or impinged shoulders ranged from 0.624-0.676. The increased rotation angle (β coefficient: 10.516°; 95% CI, 3.103-17.929) and decreased rotation radius (β coefficient: ?2.903cm; 95% CI, ?5.693 to ?0.111) were shown to be significantly related to the presence of supraspinatus tendinopathy.ConclusionsShoulders with SIS were characterized by a decreased minimal vertical AHD during dynamic examination. Abnormal subacromial metrics can develop in patients with mild (or no) rotator cuff pathologies. More prospective cohort studies are warranted to investigate the changes in subacromial motion metrics in populations at risk for painful or impinged shoulders.     

Dysphonia associated with shoulder steroid injection

Glucocorticosteroid injections into the shoulder are commonly used in the treatment of rotator cuff tendinitis. These injections rarely result in any serious complications and are generally considered a safe therapeutic intervention. Despite the extensive application of this treatment, there have been no reports of dysphonia occurring after corticosteroid injection into the subacromial space. We report the case of a 66-yr-old man with dysphonia after undergoing subacromial glucocorticosteroid injection for treatment of rotator cuff tendinitis.     

Clinical assessment of factors associated with subacromial shoulder impingement: a systematic review

Background: Physiotherapists commonly use orthopaedic special tests to reproduce subacromial shoulder impingement (SIS) pain by increasing compression or tension within the subacromial space. However, these tests do not differentiate between purported extrinsic and intrinsic mechanisms associated with SIS.

Objective: To identify, and determine the reliability and validity of clinical tests used to assess extrinsic factors associated with SIS.

Method: A scoping review identified tests for extrinsic SIS. A systematic approach was then used to search six electronic databases in July 2016 to identify clinical tests used to measure (1) posterior shoulder range, (2) cervical and/or thoracic posture, (3) 2D scapula movement, (4) rotator cuff strength. The 14 articles included in the review were assessed using a modified Downs and Black quality assessment tool.

Results: Moderate quality studies investigated 2D scapula measurements (N = 2), resting pectoralis minor length (N = 2) and rotator cuff strength (N = 5). High quality studies measured forward head position and/or thoracic posture (N = 2) and rotator cuff strength (N = 1).

Conclusion: A good level of assessment reliability and significantly less range and strength was identified in those with SIS for: posterior shoulder range (passive shoulder adduction and internal rotation and passive internal rotation in supine); isokinetic peak torque values for internal and external shoulder rotation (isokinetic testing); forward head position (lateral photograph) and thoracic range of motion (tape measure or ultrasound tomography). Good to excellent reliability was reported for lateral scapular slide test positions and resting pectoralis minor muscle length. These clinical tests should be considered for use in SIS assessment.     

The effect of negative intraarticular pressure and rotator cuff force on glenohumeral translation during simulated active elevation

OBJECTIVE: The objective of this study was to determine the effect of negative pressure in the intraarticular space and subacromial bursa, as well as rotator cuff force, on glenohumeral translation during active elevation. DESIGN: Glenohumeral translation during elevation in the scapular plane was measured under greater than, less than, and equal to physiologic rotator cuff muscle force, as well as with and without the subacromial bursa and intraarticular space vented. BACKGROUND: Negative intraarticular pressure has been shown to help stabilize the glenohumeral joint in passive motion, although the effect on translation during active motion has not been investigated.Methods: Eight cadaverous human shoulder specimens were tested in a dynamic shoulder simulator. Forces in the muscles of the rotator as well as the middle deltoid muscle were simulated using servohydraulic cylinders. Joint motion was measured using an ultrasonic motion analysis system. RESULTS: Superior translation of the humerus increased 1.2 mm (SD, 0.4) upon venting of the bursa, and 2.1 mm (SD, 1.7) upon venting of the joint capsule at 25 degrees of glenohumeral elevation in the scapular plane. At 90 degrees elevation, venting the bursa did not change superior translation but increased anterior translation 1.04 mm (SD, 1.0). Venting of the joint capsule increased superior translation by 2.8 mm (SD, 2.5). Decreasing rotator cuff force increased superior translation, while reducing it did not. CONCLUSION: The muscles of the rotator cuff and the negative pressure of the intraarticular space and the subacromial bursa stabilize the glenohumeral joint since they restrict translation in the superior and anterior directions. RelevanceIncreased glenohumeral translation and the resulting asymmetric loading may lead to arthrosis and ultimately rotator cuff arthropathy.     

Mechanisms of rotator cuff tendinopathy: Intrinsic,extrinsic, or both?

The etiology of rotator cuff tendinopathy is multi-factorial, and has been attributed to both extrinsic and intrinsic mechanisms. Extrinsic factors that encroach upon the subacromial space and contribute to bursal side compression of the rotator cuff tendons include anatomical variants of the acromion, alterations in scapular or humeral kinematics, postural abnormalities, rotator cuff and scapular muscle performance deficits, and decreased extensibility of pectoralis minor or posterior shoulder. A unique extrinsic mechanism, internal impingement, is attributed to compression of the posterior articular surface of the tendons between the humeral head and glenoid and is not related to subacromial space narrowing. Intrinsic factors that contribute to rotator cuff tendon degradation with tensile/shear overload include alterations in biology, mechanical properties, morphology, and vascularity. The varied nature of these mechanisms indicates that rotator cuff tendinopathy is not a homogenous entity, and thus may require different treatment interventions. Treatment aimed at addressing mechanistic factors appears to be beneficial for patients with rotator cuff tendinopathy, however, not for all patients. Classification of rotator cuff tendinopathy into subgroups based on underlying mechanism may improve treatment outcomes.     

肩袖损伤合并肩峰下撞击综合征的MRI表现

目的探讨肩袖损伤合并肩峰下撞击综合征的MRI影像表现。材料与方法对33例X线片无骨折但临床怀疑肩袖损伤或肩峰下撞击综合征的患者,用1.5 T MRI机检查,观察肩袖损伤及肩峰下撞击综合征在MR上的影像特征,分析两者的相关性,并与手术结果对比,计算准确率。结果 33例中肩袖损伤20例(合并肩峰下撞击综合征10例),肩峰下撞击综合征15例(合并肩袖损伤10例)。肩袖损伤和肩峰下撞击综合征术前MR诊断准确率分别约为95.0%、71.3%。结论肩关节MRI扫描对肩袖损伤及肩峰下撞击综合征的诊断有较高的临床应用价值,肩袖损伤者中至少半数合并肩峰下撞击综合征,临床和影像应予重视。     

Shoulder kinematics impact subacromial proximities: a review of the literature

BackgroundAlterations in glenohumeral and scapulothoracic kinematics have been theorized to contribute to rotator cuff pathology by impacting the magnitude of the subacromial space.ObjectiveThe purpose of this review is to summarize what is currently known about the relationship between shoulder kinematics and subacromial proximities.ConclusionsA variety of methods have been used to quantify subacromial proximities including photographs, MR imaging, ultrasonography, and single- and bi-plane radiographs. Changes in glenohumeral and scapulothoracic kinematics are associated with changes in subacromial proximities. However, the magnitude and direction of a particular motion's impact on subacromial proximities often vary between studies, which likely reflects different methodologies and subject populations. Glenohumeral elevation angle has been consistently found to impact subacromial proximities. Plane of humeral elevation also impacts subacromial proximities but to a lesser degree than the elevation angle. The impact of decreased scapulothoracic upward rotation on subacromial proximities is not absolute, but instead depends on the angle of humerothoracic elevation. The effects of scapular dyskinesis and humeral and scapular axial rotations on subacromial proximities are less clear. Future research is needed to further investigate the relationship between kinematics and subacromial proximities using more homogenous groups, determine the extent to which compression and other factors contribute to rotator cuff pathology, and develop accurate and reliable clinical measures of shoulder motion.     

The potential role of upper extremity muscle fatigue in the generation of extrinsic subacromial impingement syndrome: a kinematic perspective

Abstract

Background:

Subacromial impingement syndrome (SAIS) of the shoulder has a multi-factorial aetiology which includes both intrinsic and extrinsic mechanisms. Upper extremity muscle fatigue has been proposed as a potential causative factor in extrinsic SAIS development.

Objectives:

This review summarises the current state of knowledge regarding fatigue-induced glenohumeral (GH) and scapulothoracic (ST) kinematic changes as they relate to subacromial space reduction and subsequent SAIS. It specifically addresses evidence for mechanisms including superior humeral head translation and scapular reorientation.

Major findings:

Global upper extremity muscle fatigue elicits GH kinematic changes that increase SAIS risk. Concurrent compensatory ST kinematic alterations, primarily scapular upward rotation (UR), lessen this risk. Additionally, fatiguing protocols aimed to selectively exhaust certain muscles or muscle groups without fatiguing the rotator cuff were unsuccessful, suggesting that rotator cuff fatigue is likely for a wide range of fatiguing upper extremity tasks.

Conclusions:

Despite the compensatory response of scapular reorientation in fatigued conditions, the dimensions of the subacromial space still pose increased risk for SAIS development, and the variability in kinematic responses produces highly differential risk, particularly for those exposed to tasks requiring increased rotator cuff muscle demand.     

Immediate Effects of Thoracic Spine Manipulation Upon Shoulder Functionality in Patients With Sutured Rotator Cuff Repair: A Prospective Study

Objectives

The purpose of this study was to evaluate the immediate effect of thoracic spine manipulation upon active flexion and abduction mobility of the shoulder, spine temperature, and the size of the subacromial space as measured by ultrasound in 3 positions (internal, neutral, and external rotation) of the glenohumeral joint in patients who have undergone surgery because of subacromial impingement.

Shoulder strengthening exercises adapted to specific shoulder pathologies can be selected using new simulation techniques: a pilot study

Purpose

Shoulder strength training exercises represent a major component of rehabilitation protocols designed for conservative or postsurgical management of shoulder pathologies. Numerous methods are described for exercising each shoulder muscle or muscle group. Limited information is available to assess potential deleterious effects of individual methods with respect to specific shoulder pathologies. Thus, the goal of this pilot study was to use a patient-specific 3D measurement technique coupling medical imaging and optical motion capture for evaluation of a set of shoulder strength training exercises regarding glenohumeral, labral and subacromial compression, as well as elongation of the rotator cuff muscles.

Methods

One volunteer underwent magnetic resonance imaging (MRI) and motion capture of the shoulder. Motion data from the volunteer were recorded during three passive rehabilitation exercises and twenty-nine strengthening exercises targeting eleven of the most frequently trained shoulder muscles or muscle groups and using four different techniques when available. For each exercise, glenohumeral and labral compression, subacromial space height and rotator cuff muscles elongation were measured on the entire range of motion.

Results

Significant differences in glenohumeral, subacromial and labral compressions were observed between sets of exercises targeting individual shoulder muscles. Muscle lengths computed by simulation compared to MRI measurements showed differences of 0–5%.

Conclusions

This study represents the first screening of shoulder strengthening exercises to identify potential deleterious effects on the shoulder joint. Motion capture combined with medical imaging allows for reliable assessment of glenohumeral, labral and subacromial compression, as well as muscle-tendon elongation during shoulder strength training exercises.

     

Interobserver variation in sonography of the painful shoulder

PURPOSE: This study was conducted as a prospective assessment of interobserver variability in the sonographic evaluation of the rotator cuff. METHODS: Three musculoskeletal radiologists who had different levels of scanning experience each performed shoulder sonography on 24 consecutive patients during 1 patient visit. The diagnostic criteria full-thickness rotator cuff tear, tendon calcification, tendinosis of the supraspinatus, subacromial fluid, subacromial synovial/bursal thickening, dynamic signs of impingement, and abnormality in the long head of biceps tendon were scored, with independent observers recording the data. Statistical analysis was performed using Cohen's kappa test, with significance assessed at p values of less than 0.05. RESULTS: There was good agreement (kappa >0.60, p <0.01) between the experienced operators for full-thickness rotator cuff tear, tendon calcification, dynamic signs of impingement, and abnormality of the long head of biceps tendon. There was no significant agreement between the experienced operators and the less experienced operator in several categories, including (and importantly) full-thickness rotator cuff tears (kappa=0.18-0.21). CONCLUSIONS: In experienced hands sonography of the rotator cuff is a reproducible diagnostic test, but agreement is poor when there is marked disparity between the operators' experience levels. Our findings suggest a need for a more clearly defined training curriculum for sonography of the shoulder in radiology training programs.     

Three-dimensional ultrasound imaging of the rotator cuff: spatial compounding and tendon thickness measurement

Three-dimensional (3-D) volume reconstructions of the shoulder rotator cuff were generated from freehand ultrasound (US) scans acquired with a magnetic tracking system. Image stacks acquired with lateral overlap from multiple acoustic windows were spatially compounded to provide an extended representation of the rotator cuff tendons. A semiautomated technique was developed for measuring rotator cuff thickness from the 3-D compound volumes. Scans of phantoms and volunteer subjects were used to evaluate the accuracy and repeatability of the thickness measurements. For an in vitro phantom with known thickness, the mean difference between the true value and the automatic measurements was 0.05 +/- 0.28 mm. Thickness measurements made manually from 2-D images and automatically from 3-D volumes were different by 0.03 +/- 0.44 mm in vitro and -0.06 +/- 0.36 in vivo. Repeated thickness measurements in vivo differed by 0.06 +/- 0.36 mm. The 3-D measurement technique offers a promising method for evaluating rotator cuff tendons.     

Anatomical and biomechanical mechanisms of subacromial impingement syndrome

Subacromial impingement syndrome is the most common disorder of the shoulder, resulting in functional loss and disability in the patients that it affects. This musculoskeletal disorder affects the structures of the subacromial space, which are the tendons of the rotator cuff and the subacromial bursa. Subacromial impingement syndrome appears to result from a variety of factors. Evidence exists to support the presence of the anatomical factors of inflammation of the tendons and bursa, degeneration of the tendons, weak or dysfunctional rotator cuff musculature, weak or dysfunctional scapular musculature, posterior glenohumeral capsule tightness, postural dysfunctions of the spinal column and scapula and bony or soft tissue abnormalities of the borders of the subacromial outlet. These entities may lead to or cause dysfunctional glenohumeral and scapulothoracic movement patterns. These various mechanisms, singularly or in combination may cause subacromial impingement syndrome.     

A Systematic Comparison on Postoperative Analgesia Effect Between Subacromial and Intravenous Analgesia Pumps for Arthroscopic Rotator Cuff Repair

PurposeArthroscopic rotator cuff repair is often associated with severe postoperative pain. Various agents, routes, and modes are used for the treatment of postoperative pain with a minimum of side effects. This systematic work was conducted to compare the postoperative effect of subacromial patient-controlled analgesia with intravenous patient-controlled analgesia after an arthroscopic rotator cuff repair surgery.DesignA systematic review of relevant studies were retrieved from electronic databases and included based on criteria and eligibility.MethodsThe articles were retrieved from 1997 to 2018 by computerized searches of Scopus, PubMed, and EMBASE using different combinations of search terms, such as shoulder, rotator cuff, analgesic, analgesia, arthroscopic, pain, cuff repair, rotator cuff repair, acromion, and intravenous.FindingsA total of 10 articles were included in this study from the initial search of 778 records. Compared with subacromial procedure, the intravenous procedure helps in reducing the postoperative pain but with more side effects.ConclusionsThis study described that the direct continuous infusion of anesthetic under subacromial analgesic pump showed a greater pain relief with less side effects compared with intravenous infusion for arthroscopic rotator cuff repair.     

肩胛动力障碍及康复治疗的进展

目的 了解肩胛动力障碍的病因、临床评估和分型,以及肩胛动力障碍康复方法。方法 调查近10年国内外相关文献,总结相关内容。结果和结论 总结了肩胛动力障碍的临床评估和分型。肩胛动力障碍可继发于肩袖损伤、肩峰下撞击综合征、盂肱关节不稳、肩锁关节损伤、投掷肩、冻结肩等,肩胛运动训练可进一步改善康复效果。     

Online Information About the Effectiveness of Shoulder Surgery Is Not Based on the Best Available Evidence: A Content Analysis

ObjectiveTo summarize the proportion of consumer webpages on subacromial decompression and rotator cuff repair surgery that make an accurate portrayal of the evidence for these operations (primary outcome), mention the benefits and harms of surgery, outline alternatives to surgery, and make various surgical recommendations.DesignContent analysis.SettingOnline consumer information about subacromial decompression and rotator cuff repair surgery. Webpages were identified through (1) Google searches using terms synonymous with “shoulder pain” and “shoulder surgery” and searching “orthopedic surgeon” linked to each Australian capital city and (2) websites of relevant professional associations (eg, Australian Orthopaedic Association). Two reviewers independently identified webpages and extracted data.ParticipantsNot applicable.InterventionsNot applicable.Main Outcome MeasuresWhether the webpage made an accurate portrayal of the evidence for subacromial decompression or rotator cuff repair surgery (primary outcome), mentioned benefits and harms of surgery, outlined alternatives to surgery, and made various surgical recommendations (eg, delay surgery). Outcome data were summarized using counts and percentages.ResultsA total of 155 webpages were analyzed (n=89 on subacromial decompression, n=90 on rotator cuff repair, n=24 on both). Only 18% (n=16) and 4% (n=4) of webpages made an accurate portrayal of the evidence for subacromial decompression and rotator cuff repair surgery, respectively. For subacromial decompression and rotator cuff repair, respectively, 85% (n=76) and 80% (n=72) of webpages mentioned benefits, 38% (n=34) and 47% (n=42) mentioned harms, 94% (n=84) and 92% (n=83) provided alternatives to surgery, and 63% (n=56) and 62% (n=56) recommended delayed surgery (the most common recommendation).ConclusionsMost online information about subacromial decompression and rotator cuff repair surgery does not accurately portray the best available evidence for surgery and may be inadequate to inform patient decision making.