Comparison of 3-dimensional shoulder complex kinematics in individuals with and without shoulder pain, part 1: sternoclavicular, acromioclavicular, and scapulothoracic joints

External handheld loads affect scapular elevation and upward rotation during shoulder elevation tasks

Altered scapular kinematics is associated with shoulder pain. Resistance exercise is a common treatment; however, the effects of lifting an external load on scapular kinematics is limited. Understanding whether an external handheld load affects scapular kinematics in a healthy population can provide normal values utilized for comparison to individuals with shoulder pain. Currently, no studies have examined the effect of incrementally increased handheld loads. We defined the effects of varying external handheld loads on scapular kinematics during a shoulder elevation task. Healthy participants (n = 50) elevated their shoulder in the scapular plane over 4 trials. One trial of no loading (control) and 3 trials with incrementally increased external handheld loads. Scapular kinematic rotations and translations were measured during ascent and descent phases using 3D motion capture. Compared to no load, the highest external load during ascent increased scapular elevation [mean difference = 3.2 degrees (95%CI: 0.9, 5.4), p = 0.006], and during descent increased scapular elevation [mean difference = 3.9 degrees (95%CI: 2.8, 5.1), p < 0.001] and increased scapular upward rotation [mean difference = 4.5 degrees (95%CI: 2.4, 6.6), p < 0.001]. External handheld loads result in small increases in scapular elevation and scapular upward rotation. These results should be utilized as normal values to compare to individuals with shoulder pain.

Health-related outcomes with supervised exercise and myofascial release versus only supervised exercise in subacromial pain syndrome: a randomized controlled single-blind study

BACKGROUND

Myofascial tissue plays a critical role in shoulder joint mobility disorders. Myofascial release therapy (MFR) is frequently utilized to restore the extensibility of fascial tissue and is considered beneficial for various clinical conditions such as low back pain and ankle injuries. However, no studies have yet evaluated the effects of MFR on periscapular muscles activation and shoulder mobility in patients with subacromial pain syndrome(SAPS).

OBJECTIVE

The purpose of this study was to compare the effectiveness of MFR combined with supervised exercise(SE) and SE alone in patients with SAPS.

DESIGN

Assessor-blinded randomized controlled trial.

SETTING

Sir Run Run Shaw Hospital, Zhejiang University School of Medicine.

SUBJECTS

Subacromial pain syndrome patients.

METHODS

Fifty participants were divided into two groups: SE group and MFR + SE group, each group 25 cases. Both treatment methods were performed 5 times a week for 4 weeks.

MAIN MEASURES

Shoulder pain severity was assessed by visual analog scale (VAS); shoulder range of motion (ROM) by a goniometer; functionality by shoulder Pain and Disability Index (SPADI); and periscapular muscles activation by sEMG. All measurements were evaluated both pre- and post-treatment.

RESULTS

An ANOVA analysis indicated no significant group by time interactions for flexion ROM and resting VAS (p > 0.05). However, significant group by time interactions were found for SPADI, abduction and external rotation ROM, and activity VAS (p < 0.05). Post-hoc tests revealed significant improvements in SPADI, abduction and external rotation ROM, and activity VAS in both groups compared to pre-treatment (p < 0.05). Additionally, there were significant group by time interactions for the sEMG values of the upper trapezius and serratus anterior (p < 0.05). Post-hoc tests showed that compared to pre-treatment, the MFR + SE group had decreased upper trapezius sEMG values and increased serratus anterior sEMG values(p < 0.05), while the SE group showed increased serratus anterior sEMG values(p < 0.05). After the 4-week intervention, there were significant between-group differences in SPADI, abduction and external rotation ROM, activity VAS, and sEMG values of the upper trapezius and serratus anterior(p < 0.05).

CONCLUSION

Four weeks of MFR combined with SE can increase shoulder ROM, improve pain, and thus enhancing functional activities in patients with SAPS. Additionally, it can further improve the balance between the upper trapezius and serratus anterior to improve the dynamics of the periscapular muscles.

TRIAL REGISTRY NUMBER

ChiCTR2200061054. Date of registration 15/06/2022.

Effects of Scapular Angular Deviations on Potential for Rotator Cuff Tendon Mechanical Compression

Background

One proposed mechanism of rotator cuff disease is scapular motion impairments contributing to rotator cuff compression and subsequent degeneration.

Purpose

To model the effects of scapular angular deviations on rotator cuff tendon proximity for subacromial and internal mechanical impingement risk during scapular plane abduction.

Study Design

Descriptive laboratory study.

Methods

Three-dimensional bone models were reconstructed from computed tomography scans obtained from 10 asymptomatic subjects and 9 symptomatic subjects with a clinical presentation of impingement syndrome. Models were rotated to average scapular orientations from a healthy dataset at higher (120°) and lower (subject-specific) humeral elevation angles to investigate internal and subacromial impingement risks, respectively. Incremental deviations in scapular upward/downward rotation, internal/external rotation, and anterior/posterior tilt were imposed on the models to simulate scapular movement impairments. The minimum distance between the rotator cuff insertions and potential impinging structures (eg, glenoid, acromion) was calculated. Two-way mixed-model analyses of variance assessed for effects of scapular deviation and group.

Results

At 120° of humerothoracic elevation, minimum distances from the supraspinatus and infraspinatus insertions to the glenoid increased with ≥5° changes in upward rotation (1.6-9.8 mm, P < .001) or external rotation (0.9-5.0 mm, P≤ .048), or with ≥10° changes in anterior tilt (1.1-3.2 mm, P < .001). At lower angles, ≥20° changes in most scapular orientations significantly increased the distance between the supraspinatus and infraspinatus insertions and the acromion or coracoacromial ligament.

Conclusion

A reduction in scapular upward rotation decreases the distance between the rotator cuff tendon insertions and glenoid at 120° humerothoracic elevation. Interpretation is complicated for lower angles because the humeral elevation angle was defined by the minimum distance.

Clinical Relevance

These results may assist clinical decision making regarding the effects of scapular movement deviations in patients with rotator cuff pathology and scapular dyskinesia and may help inform the selection of clinical interventions.

In Vivo Analysis of Acromioclavicular Kinematics and Distance During Multiplanar Humeral Elevation

BACKGROUND

Knowledge of acromioclavicular (AC) joint kinematics and distance may provide insight into the biomechanical function and development of new treatment methods. However, accurate data on in vivo AC kinematics and distance between the clavicle and acromion remain unknown.

PURPOSE/HYPOTHESIS

The purpose of this study was to investigate 3-dimensional AC kinematics and distance during arm elevation in abduction, scaption, and forward flexion in a healthy population. It was hypothesized that AC kinematics and distance would vary with the elevation angle and plane of the arm.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 19 shoulders of healthy participants were enrolled. AC kinematics and distance were investigated with a combined dual fluoroscopic imaging system and computed tomography. Rotation and translation of the AC joint were calculated. The AC distance was measured as the minimum distance between the medial border of the acromion and the articular surface of the distal clavicle (ASDC). The minimum distance point (MDP) ratio was defined as the length between the MDP and the posterior edge of the ASDC divided by the anterior-posterior length of the ASDC. AC kinematics and distance between different elevation planes and angles were compared.

RESULTS

Progressive internal rotation, upward rotation, and posterior tilt of the AC joint were observed in all elevation planes. The scapula rotated more upward relative to the clavicle in abduction than in scaption (P = .002) and flexion (P = .005). The arm elevation angle significantly affected translation of the AC joint. The acromion translated more laterally and more posteriorly in scaption than in abduction (P < .001). The AC distance decreased from the initial position to 75° in all planes and was significantly greater in flexion (P < .001). The MDP ratio significantly increased with the elevation angle (P < .001).

CONCLUSION

Progressive rotation and significant translation of the AC joint were observed in different elevation planes. The AC distance decreased with the elevation angle from the initial position to 75°. The minimum distance between the ASDC and the medial border of the acromion moved anteriorly as the shoulder elevation angle increased.

CLINICAL RELEVANCE

These results could serve as benchmark data for future studies aiming to improve the surgical treatment of AC joint abnormalities to restore optimal function.

The shoulder joint complex in the throwing motion

The shoulder joint complex in the overhead athlete is organized to effectively transfer the proximally generated forces distally into the arm. The organization also protects the joints and anatomic structures against the repetitive high velocities, large ranges of motions, and compressive, shear, translational, and distraction loads in the overhead motion while placing the hand in the "launch window." Coupling of the movements of the scapula, clavicle, and humerus results in scapulohumeral rhythm (SHR). Effective SHR requires the clavicle and scapula-and, at times, the mechanically linked claviscapular segment-to move the arm into the task-specific position and motion and requires the humerus to move through the ranges of motion to achieve the specific task in the throwing motion. Alterations in SHR can negatively affect effective shoulder joint complex function in the overhead throwing motion and increase injury risk. There are 4 phases of clavicular, scapular, and claviscapular motion that are coupled with arm motion in SHR. The first 3 phases occur in arm elevation motions from 0°-90° and result in the claviscapula and humerus being placed in task-specific positions. The fourth phase is coupling of claviscapular motion with humeral motion to maintain ball-and-socket kinematics throughout the throwing motion. Alterations in this composite motion are termed "scapular dyskinesis." The dyskinesis is considered an impairment of the efficient mobility of the claviscapular segment of the shoulder complex. The most prevalent problem with scapular dyskinesis is the association of scapular protraction and consequent glenoid antetilt with alterations in humeral rotation and posterior humeral head translation to produce shoulder joint internal impingement. Task effectiveness in overhead throwing is also based on and determined by humeral range of motion, precision of humeral motion, and velocity of humeral motion, as well as humeral and arm position in 3-dimensional space. This activity requires maximum ball-and-socket kinematics to create the highest amount of concavity-compression that creates stability for the joint. There are bony and soft-tissue contributions to this stability. Injuries to the glenoid labrum are among the most common deficits that alter concavity-compression. Clinical evaluation of the shoulder joint complex in the injured throwing athlete should be comprehensive and systematic, following an evaluation pathway for proximal and distal causative factors and including observation of humeral motion. This type of evaluation can result in intervention protocols that address the pathoanatomic, pathophysiological, and pathomechanical deficits identified.

Orientation of the Scapula in the Standing Position

OBJECTIVES

A new ultrasound-based device is proposed to non-invasively measure the orientation of the scapula in the standing position to consider this parameter for Total Shoulder Arthroplasty. The aim of this study was to assess the accuracy and reliability of this device.

METHODS

Accuracy was assessed by comparing measurements made with the ultrasound device to those acquired with a three-dimensional (3D) optical localization system (Northern Digital, Canada) on a dedicated mechanical phantom. Three users performed 10 measurements on three healthy volunteers with different body mass (BMI) indices to analyze the reliability of the device by measuring the intra and interobserver variabilities.

RESULTS

The mean accuracy of the device was 0.9°± 0.7 (0.01-3.03), 1.3°± 0.8 (0.03-4.55), 1.9°± 1.5 (0.05-5.76), respectively, in the axial, coronal, and sagittal planes. The interobserver and intraobserver variabilities were excellent whatever the BMI and the users experience.

CONCLUSIONS

The device is accurate and reliable enough for the measurement of the scapula orientation in the standing position.

Changes in in vivo three dimensional shoulder kinematics following latissimus dorsi tendon transfer for irreparable posterosuperior rotator cuff tears: A systematic review with meta-analysis

BACKGROUND

Latissimus dorsi transfer is a surgical procedure that can be used for treating posterosuperior rotator cuff tears. The procedure leads to improved shoulder function via alterations in the force vector couple around the shoulder. However, there is still no consensus on the biomechanical changes resulting from latissimus dorsi transfer.

METHODS

We performed a systematic review of the literature on 3D motion analysis studies evaluating the effects of latissimus dorsi transfer on shoulder kinematics. The available data on segment and joint range of motion was extracted and subject to meta-analysis when consistent across the studies.

FINDINGS

Our meta-analysis of pre- and post-operative studies revealed a significant improvement in forward flexion and abduction following latissimus dorsi transfer. When comparing the latissimus transferred shoulder with an uninjured contralateral side the meta-analysis found no significant difference in flexion range of motion, while abduction and external rotation was significantly higher in the uninjured shoulders. The overall risk of bias was moderate to high. High heterogeneity was found in the reporting of data, which limited our ability to perform a meta-analysis across the studies for all interest outcomes.

INTERPRETATIONS

Our findings suggest that latissimus dorsi transfer for posterosuperior rotator cuff tears effectively improves shoulder flexion and abduction. External rotation is also expected to improve but at inferior levels as compared to the unaffected side. However, the heterogeneity of the reported data on 3D motion analysis studies highlights the need for better standardization in research and reporting as to conclude the impact of different joints.

The effect of myofascial and physical therapy on trunk, shoulder, and elbow movement patterns in women with pain and myofascial dysfunctions after breast cancer surgery: Secondary analyses of a randomized controlled trial

INTRODUCTION

Secondary upper limb dysfunctions are common after breast cancer treatment. Myofascial treatment may be a valuable physical therapy modality for this problem.

OBJECTIVE

To investigate the effect of myofascial therapy in addition to physical therapy on shoulder, trunk, and elbow movement patterns in women with pain and myofascial dysfunctions at the upper limb after breast cancer surgery.

DESIGN

A double-blinded randomized controlled trial.

SETTING

Rehabilitation unit of a university hospital.

PARTICIPANTS

Forty-eight women with persistent pain after finishing breast cancer treatment.

INTERVENTIONS

Over 3 months, all participants received a standard physical therapy program. The experimental (n = 24) and control group (n = 24) received 12 additional sessions of myofascial therapy or placebo therapy, respectively.

MAIN OUTCOME MEASURES

Outcomes of interest were movement patterns of the humerothoracic joint, scapulothoracic joint, trunk, and elbow, measured with an optoelectronic measurement system during the performance of a forward flexion and scaption task. Statistical parametric mapping (SPM) analyses were used for assessing the effect of treatment on movement patterns between both groups (group × time interaction effect).

RESULTS

A significantly decreased protraction and anterior tilting was found after experimental treatment. No beneficial effects on movement patterns of the humerothoracic joint, trunk, or elbow were found.

CONCLUSION

Myofascial therapy in addition to a 12-week standard physical therapy program can decrease scapular protraction and anterior tilting (scapulothoracic joint) during arm movements. Given the exploratory nature of these secondary analyses, the clinical relevance of these results needs to be investigated further.

Correlation between scapular alignment and upper extremity function in children with hemiparetic cerebral palsy

OBJECTIVES

To investigate the relationship between scapular alignment and upper extremity function.

METHODS

Eighty-five children (63 boys and 22 girls) with spastic hemiplegic cerebral palsy aged 3 to 6 years were included in the study. Scapular upward rotation was assessed using Postural Zone software, and upper extremity function was assessed using the Pediatric Arm Function Test.

RESULTS

There was a significant difference (p = .0001) in the degree of upward scapular rotation between less affected and affected sides (-41.78 ± 4.87 and -26.42 ± 6.34, respectively). There was a significant difference (p = .0001) between the function of the upper extremity of the affected side and the less affected sides (48.15 ± 14.37, 62.1 ± 6.62, respectively). Pearson Correlation Coefficient (r) was calculated, and there was a strong negative significant correlation between the degree of scapular upward rotation of the affected side, a unilateral score of the affected side, and the total score of the Pediatric Arm Function Test (r = -0.976, p = .0001 and r = -0.973, p = .0001, respectively). The correlation between symmetry index and total score of the Pediatric Arm Function Test was a strong positive significant correlation (r = 0.946, p = .0001).

CONCLUSION

The degree of upward scapular rotation was less on the affected side. Scapular alignment and symmetry may contribute to upper extremity function in children with hemiplegic cerebral palsy. Clinically, correction of scapular deviations may be considered in the rehabilitation program for children with hemiplegic cerebral palsy. This study suggests further experimental studies to find the cause and effect.

Scapular dyskinesis after treatment of proximal humerus fracture, a 3-dimensional motion analysis and clinical outcomes

BACKGROUND

The alteration of scapular kinematics can predispose patients to shoulder pathologies and dysfunction. Previous literature has associated various types of shoulder injuries with scapular dyskinesis, but there are limited studies regarding the effect that proximal humeral fractures (PHFs) have on scapular dyskinesis. This study aims to determine the change in scapulohumeral rhythm following treatment of a proximal humerus fracture as well as differences in shoulder motion and functional outcomes among patients who presented with or without scapular dyskinesis. We hypothesized that differences in scapular kinematics would be present following treatment of a proximal humerus fracture, and patients who presented with scapular dyskinesis would subsequently have inferior functional outcome scores.

METHODS

Patients treated for a proximal humerus fracture from May 2018 to March 2021 were recruited for this study. The scapulohumeral rhythm and global shoulder motion were determined using a 3-dimensional motion analysis (3DMA) and the scapular dyskinesis test. Functional outcomes were then compared among patients with or without scapular dyskinesis, including the SICK (scapular malposition, inferomedial border prominence, coracoid pain and malposition, and dyskinesis of scapular movement) Scapula Rating Scale, the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), the visual analog scale (VAS) for pain, and the EuroQol-5 Dimension 5-Level questionnaire (EQ-5D-5L).

RESULTS

Twenty patients were included in this study with a mean age of 62.9 ± 11.8 years and follow-up time of 1.8 ± 0.2 years. Surgical fixation was performed in 9 of the patients (45%). Scapular dyskinesis was present in 50% of patients (n = 10). There was a significant increase in scapular protraction on the affected side of patients with scapular dyskinesis during abduction of the shoulder (P = .037). Additionally, patients with scapular dyskinesis demonstrated worse SICK scapula scores (2.4 ± 0.5 vs. 1.0 ± 0.4, P = .024) compared to those without scapular dyskinesis. The other functional outcome scores (ASES, VAS pain scores, and EQ-5D-5L) showed no significant differences among the 2 groups (P = .848, .713, and .268, respectively).

CONCLUSIONS

Scapular dyskinesis affects a significant number of patients following treatment of their PHFs. Patients presenting with scapular dyskinesis exhibit inferior SICK scapula scores and have more scapular protraction during shoulder abduction compared to patients without scapular dyskinesis.

Specific versus general exercise programme in adults with subacromial impingement syndrome: a randomised controlled trial

Objectives

Current evidence on the clinical effectiveness about the different types of exercises in the subacromial impingement syndrome (SIS) remains controversial. This study aims to compare the short-term (at 5 weeks) effects of a specific exercise programme with a general exercise programme on shoulder function in adults with SIS.

Methods

In total, 52 adults with SIS were randomly allocated to 5 weeks to perform specific exercises (experimental group, n=26) or general exercises (control group, n=26). The primary outcome was change in shoulder function, it was assessed using the Shoulder Pain and Disability Index (SPADI) from baseline to 5 weeks. Secondary end points included changes in upper limb function (Disabilities of the Arm, Shoulder, and Hand (DASH) Questionnaire), pain intensity (Visual Analog Scale (VAS)) and kinesiophobia (Tampa Scale of Kinesiophobia (TSK)).

Results

All participants completed the trial. The between-group differences at 5 weeks were: SPADI, 13.5 points (95% CI: 4.3 to 15.6; ƞ2=0.22; p=0.001); DASH, 10.1 points (95% CI: 5.6 to 15.2; ƞ2=0.27; p<0.001); VAS at rest, 0.2 cm (95% CI: 0.1 to 0.3; ƞ2=0.07; p=0.553); VAS on movement, 1.7 cm (95% CI: 0.9 to 2.2; ƞ2=0.24; p<0.001); and TSK, 16.3 points (95% CI: 13.2 to 15.3; ƞ2=0.33; p<0.001). All differences favoured the experimental group and effect sizes were medium to large for most outcomes. Mediation analyses showed that the effect of the specific exercises on shoulder function was mediated by kinesiophobia (β=2.800; 95% CI: 1.063 to 4.907) and pain on movement (β= -0.690; 95% CI: -1.176 to -0.271).

Conclusion

In adults with SIS, specific exercises may have a larger effect than general exercises. However, most differences did not reach the minimum threshold to be considered clinically important and the evidence to support exercise as standard treatment warrant further study.

Trial registration number

Brazilian Registry of Clinical Trials UTN number U111-1245-7878. Registered on 17 January 2020 (https://ensaiosclinicos.gov.br/rg/RBR-4d5zcg).

Accuracy of measuring scapular position and motion with a novel motion capture system

Background

Scapula kinematics is recognized to be a crucial variable in shoulder dysfunction. Nevertheless, quantitative scapula tracking and measurement are not part of the current clinical evaluation. The main concern is measurement accuracy.

Methods

To assess the accuracy of the wearable sensor technology Showmotion a cadaver experiment was designed, allowing a direct comparison between sensors directly pinned to the scapula and superficial sensors. A measurement protocol was adopted to evaluate errors in measurement, mimicking the suggested in vivo evaluation. Sensors were simultaneously placed above (supraspinal) and below (infraspinal) the scapular spine to determine if one placement resulted in fewer errors compared to the other.

Results

Mean and standard deviations of the supraspinal sensor root mean square error (RMSE) in flexion-extension movements resulted in 3.59° ± 2.36°, 4.73° ± 2.98°, and 6.26° ± 3.62° for upward-downward rotation (up-down), anterior-posterior tilt and internal-external (intra-extra) rotation, respectively, while 2.16° ± 1.21°, 2.20° ± 1.02°, and 4.46° ± 2.16° for the infraspinal sensor. In abduction-adduction movements, mean and standard deviations of the supraspinal sensor RMSE resulted in 4.26° ± 2.98°, 5.68° ± 4.22°, and 7.04° ± 4.36° for up-down rotation, anterior-posterior tilt, and intra-extra rotation, respectively, while 2.38° ± 1.63°, 2.47° ± 1.77°, and 4.92° ± 3.14° for the infraspinal sensor. The same behavior was confirmed in shrug movements, where 4.35° ± 3.24°, 4.63° ± 3.09°, and 5.34° ± 6.67° are mean and standard deviations of the supraspinal sensor RMSE for up-down rotation, anterior-posterior tilt, and intra-extra rotation, respectively, while 2.76° ± 1.87°, 2.83° ± 2.53°, and 4.68° ± 5.22° for the infraspinal sensor.

Conclusion

This method of quantitative assessment of scapular motion is shown to have good accuracy and low error between the sensor measurements and actual bone movement in multiple planes of scapular motion, both over the entire range of motion and in its individual segment intervals. The decreased amount of error with the infraspinal sensor placement suggests that placement is ideal for clinical quantitative assessment of scapular motion.

Between Two Rocks and in a Hard Place: Reflecting on the Biomechanical Basis of Shoulder Occupational Musculoskeletal Disorders

OBJECTIVE

The aim was to review the biomechanical origins of occupational shoulder damage, while considering the complexity of shoulder mechanics and musculoskeletal consequences of diverse task demands.

BACKGROUND

Accessible measures of physical exposures are the primary focus of occupational shoulder assessments and analyses. This approach has led to guidelines and intervention strategies that are often inadequate for mitigating shoulder disorders amongst the complexity of modern workplace demands. Integration of complex shoulder mechanics into occupational assessments, analyses, and interventions is critical for reducing occupational shoulder injury risk.

METHOD

This narrative review describes shoulder biomechanics in the context of common injury mechanisms and consequent injuries, with a particular focus on subacromial impingement syndrome. Several modulators of shoulder injury risk are reviewed, including fatigue, overhead work, office ergonomics considerations, and pushing and pulling task configurations.

RESULTS

Relationships between work requirements, muscular demands, fatigue, and biomechanical tissue loads exist. This review highlights that consideration of specific workplace factors should be integrated with our knowledge of the intricate arrangement and interpersonal variability of the shoulder complex to proactively evaluate occupational shoulder demands and exposures.

CONCLUSION

A standard method for evaluating shoulder muscle exposures during workplace tasks does not exist. An integrated approach is critical for improved work design and prevention of shoulder tissue damage and accompanying disability.

APPLICATION

This review is particularly relevant for researchers and practitioners, providing guidance for work design and evaluation for shoulder injury prevention by understanding the importance of the unique and complex mechanics of the shoulder.

A novel method for estimating sternoclavicular posterior rotation with promising accuracy: A validity comparison with minimizing acromioclavicular rotation approach

The human shoulder complex's motion is modeled by nine rotational degrees of freedom (DoF) at the sternoclavicular (SC), acromioclavicular (AC), and glenohumeral joints. Non-invasive measurement of these rotations is desirable for shoulder kinematic assessment or musculoskeletal modeling. Accuracy of the conventional method for estimating SC posterior rotation is unclear and might be overestimated because it assumes no rotation in the AC joint. We aimed to explore whether our new method, allowing AC rotation, provides a more accurate estimation of SC posterior rotation than the conventional method. We compared estimates by both methods, in 18 postures among 8 healthy men, with those measured by the registration method from magnetic resonance images. Posthoc analyses showed significant differences between the registration and conventional methods in all 18 postures and in only one posture when compared to our method. While the conventional method tended toward overestimation and showed a 22.7° root-mean-square error for all postures, the new method had greater accuracy (6.8° root-mean-square error). By combining this method with the scapulothoracic rotation measurement method and other traditional methods, it should be possible to indirectly measure 3-DoF AC rotation, implying that non-invasive measurement of all 9-DoF rotations of the shoulder complex would now be possible.

Comparative Analysis of Muscle Synergy between Patients with Shoulder Impingement Syndrome and Healthy Controls: A Preliminary Study

Shoulder impingement syndrome can be caused by a muscle imbalance around the shoulder joint. It would be beneficial for therapy to implement rehabilitation exercises based on intermuscular coordination in order to achieve muscle balance. This study presents the muscle synergy characteristics of patients with shoulder impingement syndrome, which can be used to develop rehabilitation exercises. During pick and place task, the muscle synergy obtained from eight shoulder muscles in patients and healthy subjects was compared. The experimental results revealed that patients have low contributed muscle synergy structures for the serratus anterior and infraspinatus.Clinical relevance- This proposes that patients with shoulder impingement syndrome may have abnormal muscle synergy structure which can be used for assessment.

Kinematic, electromyographic and isokinetic measurements for the management of shoulder subacromial pain syndrome: A systematic review

BACKGROUND

Subacromial shoulder pain syndrome is a very common and challenging musculoskeletal disorder. Kinematics, electromyographic muscle activity and isokinetic dynamometry are promising non-invasive movement analysis tools to improve understanding of this condition. No review has combined their results to provide a better understanding of the effects of subacromial pain syndrome on shoulder movement. This systematic review aimed to synthesise the associations between exposure to shoulder pain due to subacromial pain syndromes or subacromial impingement and changes in shoulder movement measures.

METHODS

The databases were Scholar google, Pubmed, Science Direct, Scopus and the Cochrane Library. We included studies that observed the association of the presence of subacromial pain syndromes or subacromial impingement with changes in shoulder motion measures.

FINDINGS

Seventeen studies with 943 participants were included. The main kinematic change was a lower scapular posterior during abduction in the subacromial pain syndrome group with a "low" level of evidence (standardised mean difference = -0.61, 95% confidence interval [-0.80; -0.43]). The main electromyographic change was an earlier onset of activation of the upper trapezius in the subacromial pain syndrome group, with a "moderate" level of evidence (standardised mean difference = 1.01, 95% confidence interval: [-2.97; 0.96]). The main isokinetic change was a lower peak internal rotator torque in the subacromial pain syndrome group, with a 'low' level of evidence (standardised mean difference = -0.41, 95% confidence interval: [-0.53; -0.29]).

INTERPRETATION

The variables measured during movement are associated with subacromial pain syndrome or subacromial impingement syndrome. Consistency between the results supports the importance of scapula biomechanics measurements in these conditions.

Scapular Kinematics and Patterns of Scapular Dyskinesis in Rotator Cuff Tears: A Prospective Cohort Study

Scapular dyskinesis (SD) is a condition of loss of normal mobility or function of the scapula. SD is frequently observed in patients with other shoulder disorders, such as rotator cuff (RC) tears. This study evaluates the different presentations in clinical outcomes and range of motions (ROMs) in patients suffering from RC tears with and without SD. A total of 52 patients were enrolled, of which 32 patients with RC tears and SD (group A) and 20 patients with RC tears without SD (group B). Statistically significant differences between the groups in terms of clinical outcomes were identified. There were statistically significant differences in terms of flexion (p = 0.019), extension (p = 0.015), abduction (p = 0.005), and external rotation at 90° (p = 0.003) and at 0° (p = 0.025). In conclusion, this prospective study demonstrated that SD influences the clinical presentation of patients with RC tears in terms of clinical outcomes and ROMs, apart from internal rotation. Further studies will need to show whether these differences occur regardless of SD type.

Exercise for rotator cuff tendinopathy: Proposed mechanisms of recovery

Rotator cuff (RC) tendinopathy is a common recurrent cause of shoulder pain, and resistance exercise is the first-line recommended intervention. Proposed causal mechanisms of resistance exercise for patients with RC tendinopathy consist of four domains: tendon structure, neuromuscular factors, pain and sensorimotor processing, and psychosocial factors. Tendon structure plays a role in RC tendinopathy, with decreased stiffness, increased thickness, and collagen disorganization. Neuromuscular performance deficits of altered kinematics, muscle activation, and force are present in RC tendinopathy, but advanced methods of assessing muscle performance are needed to fully assess these factors. Psychological factors of depression, anxiety, pain catastrophizing, treatment expectations, and self-efficacy are present and predict patient-reported outcomes. Central nervous system dysfunctions also exist, specifically altered pain and sensorimotor processing. Resisted exercise may normalize these factors, but limited evidence exists to explain the relationship of the four proposed domains to trajectory of recovery and defining persistent deficits limiting outcomes. Clinicians and researchers can use this model to understand how exercise mediates change in patient outcomes, develop subgroups to deliver patient-specific approach for treatment and define metrics to track recovery over time. Supporting evidence is limited, indicating the need for future studies characterizing mechanisms of recovery with exercise for RC tendinopathy.

Shoulder Kinematics of Axillary Web Syndrome in Women Treated for Breast Cancer

OBJECTIVE

To better understand how the shoulder moves in breast cancer survivors with axillary web syndrome (AWS), we compared 3-dimensional (3D) shoulder kinematics during shoulder elevation among breast cancer survivors with and without AWS 5 years postoperatively. Although research consistently shows decreased shoulder range of motion with AWS, we do not understand the underlying biomechanics.

DESIGN

Nested case control study.

SETTING

University Academic Breast Center.

PARTICIPANTS

Twenty-five women who had surgery 5 years previously for unilateral breast cancer with the removal of at least 1 lymph node participated in this study (N=25). Twelve participants had AWS; 13 women did not have AWS.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Three-dimensional shoulder kinematic data during shoulder forward flexion, scapular plane abduction, and coronal plane abduction were collected using 3D electromagnetic motion tracking. Kinematic data were extracted at 30°, 60°, 90°, and 120° of arm elevation for scapular upward rotation, internal rotation, and posterior tilt as well as for glenohumeral external rotation.

RESULTS

Women with AWS demonstrated 15.2° less scapular upward rotation at 120° humerothoracic elevation (95% confidence interval [-25.2, -5.2], P=.005), regardless of plane. No significant between-group differences were found for any other angle of scapular upward rotation, nor for scapular internal rotation, scapular posterior tilt, or glenohumeral axial rotation at any angle.

CONCLUSIONS

Five years after surgery for breast cancer, women diagnosed with AWS have altered scapulohumeral kinematics that may place them at an increased risk of shoulder pain based on existing kinematic literature in healthy cohorts. This information can help guide rehabilitation programs for breast cancer survivors to facilitate pain-free upper extremity function after treatment.

Managing Scapular Dyskinesis

Scapular dyskinesis, the impairment of optimal scapular position and motion, is common in association with shoulder injury. A comprehensive evaluation process can show the causative factors and lead to effective treatment protocols. The complexity of scapular motion and the integrated relationship between the scapula, humerus, trunk, and legs suggest a need to develop rehabilitation programs that involve all segments working as a unit rather than isolated components. This is best accomplished with an integrated rehabilitation approach that includes rectifying deficits in mobility, strength, and motor control but not overtly focusing on any one area.

The influence of shoulder position during multi-joint exercises in the relative scapular muscles activity in symptomatic and asymptomatic conditions

BACKGROUND

Scapular muscles changes, as increased upper trapezius activity and decreased middle and lower trapezius and serratus anterior muscle activity, have been demonstrated in shoulder pain specific or non-specific conditions. Shoulder external rotation exercises have been recommended to improve scapular activity in shoulder pain.

OBJECTIVE

To evaluate the relative scapular muscles activity during multi-joint exercises combining shoulder external rotation, trunk rotation and scapular squeeze.

METHODS

Forty-one participants with and without shoulder pain were assessed in a cross-sectional study. They performed isometric multi-joint exercises at 0∘ and 90∘ of shoulder abduction with and without support. The relative activity of upper, middle, and lower trapezius and serratus anterior (upper/middle and lower portions) was measured through electromyography. The scapular muscular balance was assessed by the ratio between relative activity of the upper trapezius and the other muscles.

Differences in Tridimensional Shoulder Kinematics between Asymptomatic Subjects and Subjects Suffering from Rotator Cuff Tears by Means of Inertial Sensors: A Cross-Sectional Study

Background: The aim of this study was to analyze differences in three-dimensional shoulder kinematics between asymptomatic subjects and patients who were diagnosed with rotator cuff tears. Methods: This cross-sectional study recruited 13 symptomatic subjects and 14 asymptomatic subjects. Data were obtained from three inertial sensors placed on the humerus, scapula and sternum. Kinematic data from the glenohumeral, scapulothoracic and thoracohumeral joints were also calculated. The participants performed shoulder abductions and flexions. The principal angles of movements and resultant vectors in each axis were studied. Results: The glenohumeral joint showed differences in abduction (p = 0.001) and flexion (p = 0.000), while differences in the scapulothoracic joint were only significant during flexion (p = 0.001). The asymptomatic group showed higher velocity values in all sensors for both movements, with the differences being significant (p < 0.007). Acceleration differences were found in the scapula during abduction (p = 0.001) and flexion (p = 0.014), as well as in the sternum only during shoulder abduction (p = 0.022). Conclusion: The results showed kinematic differences between the patients and asymptomatic subjects in terms of the mobility, velocity and acceleration variables, with lower values for the patients.

The stress and strain pattern in the ligaments of the acromioclavicular joint using a quasi-static model

BACKGROUND

The precise role of the acromioclavicular and coracoclavicular ligaments during shoulder motion is unclear. We evaluate changes in the stress-strain distribution of the acromioclavicular joint's ligaments during different shoulder passive motion positions.

METHODS

A 3D acromioclavicular joint model was reconstructed. A constitutive hyperelastic model was used for the ligaments. The kinematics of the shoulder girdle was taken to simulate shoulder abduction (Motion 1) and horizontal adduction (Motion 2). A computer-generated quasi-static and non-linear finite element model was used to predict the 3D stress-strain distribution pattern of the acromioclavicular ligament and the coracoclavicular ligament complex.

FINDINGS

In motion 1, from 20 to 90° the peak von Mises stress was found in the conoid (4.14 MPa) and the anteroinferior bundle (2.46 MPa), while from 90 to 120° it was found in the conoid and the trapezoid. However, there were no significant differences between the mean stress values between anteroinferior bundle and trapezoid throughout the motion (p = 0.98). In Motion 2, from 20 to 80° the maximum equivalent elastic strain was found in the anteroinferior bundle (0.68 mm/mm) and the conoid (0.57 mm/mm), while from 80 to 100° it was higher in the conoid (0.88 mm/mm) than in the anteroinferior bundle (0.77 mm/mm).

INTERPRETATION

The coracoclavicular ligament complex demonstrated a high stress-strain concentration during simulated passive shoulder abduction. Additionally, it was shown that the acromioclavicular ligament plays an important role in joint restraint during passive horizontal adduction, changing the primary role with the trapezoid and conoid at different motion intervals.

Effects of core stability on shoulder and spine kinematics during upper limb elevation: A sex-specific analysis

BACKGROUND

Upper limb elevation begins with core stabilization, but the effects of core stability on shoulder and spine kinematics are unknown. Sex differences also exist in shoulder kinematics and core stability.

OBJECTIVE

To clarify the effects of core stability on shoulder and spine kinematics during upper limb elevation by taking sex into account.

DESIGN

Cross-sectional.

METHODS

The Sahrmann Core Stability Test, lumbar spine motor control test battery, and Y Balance Test (lower and upper quarters) were performed in 50 healthy young adults. For each test, a principal component (PC) analysis was conducted according to sex; the overall core stability score was calculated. The top and bottom third of the PC scores were defined as high and low score groups, respectively (each group: nine males and eight females). Shoulder and spine kinematics during upper limb elevation were compared separately for males and females.

RESULTS

Spinal extension was greater in the low score group by a maximum of 1.9° in males (P < .001; η² = 0.068) and 1.6° in females (P < .001; η² = 0.141). In the low score group of females, the scapular posterior tilt was a maximum of 5.6° smaller (P < .001; η² = 0.221) and glenohumeral elevation was a maximum of 4.5° larger (P < .001; η² = 0.113) than the high score group of females.

CONCLUSION

Core stability affected spine and female scapular and glenohumeral kinematics during upper limb elevation. Core stability may be one of the potential contributors to shoulder kinematics, particularly in females.

Evidence of rotator cuff disease after breast cancer treatment: scapular kinematics of post-mastectomy and post-reconstruction breast cancer survivors

BACKGROUND

Breast cancer survivors may be at risk of experiencing rotator cuff disease after treatment. Biomechanical alterations following surgery potentially predispose survivors to develop this disorder.

OBJECTIVE

To examine scapular kinematics in breast cancer survivors with and without impingement pain during an overhead reach task.

DESIGN

A cross-sectional study.

METHODS

Three surgery groups were included: non-cancer controls, mastectomy-only survivors and post-reconstruction survivors. Breast cancer survivor groups were also categorized by the presence of impingement pain. Scapular motion was tracked during an overhead reach task, performed separately by both arms. Maximum scapular internal rotation, upward rotation and tilt were calculated. Two-way analyses of variance with interactions (p < .05) were used to test the effects of group (control, mastectomy-only, reconstruction) and impingement pain (pain, no pain) on each variable within a (left/right) side.

RESULTS

Scapular kinematics varied with the group by pain interaction. On the right side, the mastectomy-pain group had reduced upward rotation, while the reconstruction-pain group had higher upward rotation (mastectomy-only: 22.9° vs. reconstruction: 31.2°). On the left side, the mastectomy-pain group had higher internal rotation, while the reconstruction-pain group had reduced internal rotation (mastectomy-only: 45.1° vs. reconstruction: 39.3°). However, time since surgery was longer in the mastectomy-pain group than reconstruction-pain group, suggesting there may be a temporal component to kinematic compensations.

CONCLUSIONS

There are kinematic alterations in breast cancer survivors that may promote future development of rotator cuff disease. Compensations may begin as protective and progress to more harmful alterations with time.KEY MESSAGESScapular kinematics varied with surgery and pain interaction: upward rotation was lower and internal rotation higher in mastectomy-pain group, while upward rotation was higher and internal rotation lower in reconstruction-pain group.Kinematics alterations may also be associated with time since surgery, as the mastectomy-pain group had longer time since surgery than the reconstruction-pain group.Kinematic alterations may transition from protective to harmful over time.In-depth analyses by reconstruction type are needed to determine surgery-specific effects on kinematics and their potential impact on the development of rotator cuff disease.

Assessment of three-dimensional rotation of the shoulder complex and scapulohumeral rhythm during sagittal movement

BACKGROUND

Due to the influence of spinal and respiratory movements, it is difficult to accurately measure the range of motion of each joint.

OBJECTIVE

To conduct a three-dimensional (3D) measurement of each joint in the shoulder complex in different postures in the sagittal plane of the upper extremity.

METHODS

Thirteen healthy adults with no history of shoulder surgery for trauma or chronic pain were enrolled in the present study. The computed tomography (CT) imaging data of the shoulder complex were acquired in four postures via the reconstruction and alignment of 3D images. The angles of the postural changes were measured, and rotation vectors were used for descriptions and statistical analyses.

RESULTS

There was a statistical difference in the rotation angles between the dominant and non-dominant sides of the sternoclavicular joint when the posture changed from a resting position to a posterior inferior position. During the postural change from a resting position to a horizontal position, the regression coefficient (β) of the humerothoracic joint to the sternoclavicular joint was 0.191, and the β of the humerothoracic joint to the glenohumeral joint was 0.621. During the postural change from the horizontal position to the rear upper position, the β of the humerothoracic joint to the sternoclavicular joint was 0.316, and the β of the humerothoracic joint to the glenohumeral joint was 0.845. During the postural change from the resting position to the rear lower position, the β of the humerothoracic joint to the glenohumeral joint was 0.991.

CONCLUSION

The application of the image alignment technique enabled the direct and accurate measurement of the bony structures of the shoulder joint. The helical approach accurately described the scapulohumeral rhythm during 3D motion. There was a scapulohumeral rhythm of the shoulder complex during 3D composite sagittal movement, with different ratios for different joints and postures.

The short-term effectiveness of scapular focused taping on scapular movement in tennis players with shoulder pain: A within-subject comparison

This study aimed to investigate the short-term effectiveness of scapular focused taping (SFT) on scapular position and kinematics during the tennis serve among professional players with and without shoulder pain. The cohort included 7 players who had no history of non-shoulder pain (NSP) and 6 players with shoulder pain (SP). All participants performed tennis flat serves while the Qualisys motion capture system recorded three-dimensional scapular kinematic data according to the International Society of Biomechanics recommendations. SFT was applied to the participants' torso aligned with the lower trapezius, and the same movements were repeated. In the SP group, the scapula was tilted more posteriorly after the application of SFT as compared to before at ball release and maximally externally rotated humerothoracic joint during tennis serve (t = -5.081, P = .004 and t = -2.623, P = .047, respectively). In the NSP group, the scapula was tilted more posteriorly with SFT as compared to without at first 75% timing of the cocking phase and maximally externally rotated humerothoracic joint (t = -3.733, P = .010 and t = -2.510, P = .046, respectively). And the SP group exhibited a more rotated scapula externally after the application of SFT as compared to before at Ball impact (t = 5.283, P = .003). SFT had a positive immediate effect on the scapular posterior tilting and external rotation during certain phases of the tennis serve among tennis athletes with and without shoulder pain. These findings may help clinicians and sports practitioners to prevent and rehabilitate shoulder injuries for overhead athletes. Level of evidence: Level III; Case-Control Design; Comparative Study.

Treatment of Failed Coracoclavicular Ligament Reconstructions: Primary Acromioclavicular Ligament and Capsular Reconstruction and Revision Coracoclavicular Ligament Reconstruction

Acromioclavicular (AC) joint dislocations are a common injury affecting 2 of every 10,000 people in the general population and comprise 9% to 12% of all injuries to the shoulder. Most injuries occur through contact activity, which drives the acromion inferiorly with the clavicle remaining in its anatomic position, initiating a cascade of injury propagating from the AC ligament followed by failure of the coracoclavicular ligaments. Many techniques have been described for AC joint injuries, without a consensus gold standard. The revision setting offers even less consensus on treatment options and countless difficulties for surgeons. There have been more than 60 described procedures regarding AC and coracoclavicular ligament reconstructions, with significant controversy regarding the optimal intervention for each injury. When these techniques fail, it is important to pinpoint the mechanism of failure to construct a successful plan for revision. The purpose of this Technical Note is to describe our preferred method of primary AC and revision coracoclavicular reconstruction using a combination of autograft and allograft semitendinosus as well as TightRope fixation.

Shoulder structure and function: The impact of osteoarthritis and rehabilitation strategies

STUDY DESIGN

Invited review.

BACKGROUND

Shoulder osteoarthritis can result in significant functional deficits. To improve diagnosis and treatment, we must better understand the impact of osteoarthritis on shoulder biomechanics and the known mechanical benefits of currently available treatments.

PURPOSE

The purpose of this paper is to present up-to-date data on the effects of osteoarthritis and rehabilitation on the biomechanical parameters contributing to shoulder function. With this goal, we also reviewed the anatomy and the ranges of motion of the shoulder.

METHODS

A search of electronic databases was conducted. All study designs were included to inform this qualitative, narrative literature review.

RESULTS

This review describes the biomechanics of the shoulder, the impact of osteoarthritis on shoulder function, and the treatment of shoulder osteoarthritis with an emphasis on rehabilitation.

CONCLUSIONS

The shoulder is important for the completion of activities of daily living, and osteoarthritis of the shoulder can significantly reduce shoulder motion and arm function. Although shoulder rehabilitation is an integral treatment modality to improve pain and function in shoulder osteoarthritis, few high-quality studies have investigated the effects and benefits of shoulder physical and occupational therapies. To advance the fields of therapy and rehabilitation, future studies investigating the effects of therapy intensity, therapy duration, and the relative benefits of therapy subtypes on shoulder biomechanics and function are necessary.

In Vitro Simulation of Shoulder Motion Driven by Three-Dimensional Scapular and Humeral Kinematics

In vitro simulation of three-dimensional (3D) shoulder motion using in vivo kinematics obtained from human subjects allows investigation of clinical conditions in the context of physiologically relevant biomechanics. Herein, we present a framework for laboratory simulation of subject-specific kinematics that combines individual 3D scapular and humeral control in cadavers. The objectives were to: (1) robotically simulate seven healthy subject-specific 3D scapulothoracic and glenohumeral kinematic trajectories in six cadavers, (2) characterize system performance using kinematic orientation accuracy and repeatability, and muscle force repeatability metrics, and (3) analyze effects of input kinematics and cadaver specimen variability. Using an industrial robot to orient the scapula range of motion (ROM), errors with repeatability of ±0.1 mm and <0.5 deg were achieved. Using a custom robot and a trajectory prediction algorithm to orient the humerus relative to the scapula, orientation accuracy for glenohumeral elevation, plane of elevation, and axial rotation of <3 deg mean absolute error (MAE) was achieved. Kinematic accuracy was not affected by varying input kinematics or cadaver specimens. Muscle forces over five repeated setups showed variability typically <33% relative to the overall simulations. Varying cadaver specimens and subject-specific human motions showed effects on muscle forces, illustrating that the system was capable of differentiating changes in forces due to input conditions. The anterior and middle deltoid, specifically, showed notable variations in patterns across the ROM that were affected by subject-specific motion. This machine provides a platform for future laboratory studies to investigate shoulder biomechanics and consider the impacts of variable input kinematics from populations of interest, as they can significantly impact study outputs and resultant conclusions.

Relationship between scapular control during isometric shoulder flexion and scapular motion during baseball pitching: a cross-sectional study

Background

A baseball pitcher with decreased scapular control may not be able to achieve suitable scapular motion at maximum shoulder external rotation (MER) of baseball pitching during the pitching action. It is common clinically to compare scapular control of the throwing and non-throwing arms to detect side-to-side differences. However, it remains unclear whether scapular control is different between the throwing and non-throwing arms. Moreover, no data exist on the relationship between scapular control and scapular motion at MER of pitching. Primarily, this study aimed to compare scapular control during isometric shoulder flexion between the throwing and non-throwing arms. Secondly, this study aimed to investigate the relationship between scapular control during isometric shoulder flexion and scapular motion at MER of pitching.

Methods

Fifteen healthy collegiate baseball pitchers (age, 20.2 ± 1.9 years; height, 1.76 ± 0.05 m; body mass, 73.3 ± 6.7 kg) were recruited. An optical motion tracking system was used to assess scapular motion. Scapular control was defined as the amount of change in the scapular internal rotation angle, downward rotation angle, and anterior tilt angle during isometric shoulder flexion. We assessed scapular position at MER of pitching.

Results

No significant differences were detected for any of the scapular angles during isometric shoulder flexion between the throwing and non-throwing arms. The amount of change in the scapular internal rotation angle, scapular downward rotation angle, and scapular anterior tilt angle during isometric shoulder flexion had a significant relationship with the scapular downward rotation angle at MER.

Conclusions

No side-to-side difference was noted in scapular control during isometric shoulder flexion in healthy collegiate baseball pitchers at the group level. Further studies are required to understand the side-to-side differences at the individual level. Additionally, there was a relationship between scapular control during isometric shoulder flexion and scapular position at MER. These findings suggest that clinicians may consider using isometric shoulder flexion to assess scapular control in baseball pitchers.

Three-Dimensional Kinematics during Shoulder Scaption in Asymptomatic and Symptomatic Subjects by Inertial Sensors: A Cross-Sectional Study

Shoulder kinematics is a measure of interest in the clinical setting for diagnosis, evaluating treatment, and quantifying possible changes. The aim was to compare shoulder scaption kinematics between symptomatic and asymptomatic subjects by inertial sensors. Methods: Scaption kinematics of 27 subjects with shoulder symptomatology and 16 asymptomatic subjects were evaluated using four inertial sensors placed on the humerus, scapula, forearm, and sternum. Mobility, velocity, and acceleration were obtained from each sensor and the vector norm was calculated from the three spatial axis (x,y,Z). Shoulder function was measured by Upper Limb Functional Index and Disabilities of the Arm, Shoulder, and Hand questionnaires. One way ANOVA was calculated to test differences between the two groups. Effect size was calculated by Cohen’s d with 95% coefficient Intervals. Pearson’s correlation analysis was performed between the vector norms humerus and scapula kinematics against DASH and ULFI results in symptomatic subjects. Results: The asymptomatic group showed higher kinematic values, especially in the humerus and forearm. Symptomatic subjects showed significantly lower values of mobility for scapular protraction-retraction (Cohen’s d 2.654 (1.819–3.489) and anteriorisation-posteriorisation (Cohen’s d 1.195 (0.527–1.863). Values were also lower in symptomatic subjects for velocity in all scapular planes of motion. Negative correlation showed that subjects with higher scores in ULFI or DASH had lower kinematics values. Conclusion: Asymptomatic subjects tend to present greater kinematics in terms of mobility, velocity, and linear acceleration of the upper limb, and lower humerus and scapula kinematics in symptomatic subjects is associated with lower levels of function.

Nonoperative Management of Traumatic Acromioclavicular Joint Injury: A Clinical Commentary with Clinical Practice Considerations

Traumatic injuries of the acromioclavicular joint result in pain and potentially long-term alterations in scapulohumeral rhythm that occurs due to disruption of the clavicular strut function which is integral to scapular kinematics. Nonoperative treatment remains a valid option in most acromioclavicular joint injuries with the potential of minimizing pain and restoring scapulohumeral rhythm. However, few studies have provided nonoperative treatment details. Therefore, the purpose of this clinical commentary is to discuss the rationale, indications, and techniques of nonoperative treatment and present an organized approach for evaluating and managing such patients based on the best available evidence. Attention will be focused on identifying the treatment methods employed and the results/outcomes of such treatments.

Level of Evidence

5.

Usefulness of the acromioclavicular joint cross-sectional area as a diagnostic image parameter of acromioclavicular osteoarthritis

BACKGROUND

Acromioclavicular joint (ACJ) space narrowing has been considered to be an important diagnostic image parameter of ACJ osteoarthritis (ACJO). However, the morphology of the ACJ space is irregular because of osteophyte formation, subchondral irregularity, capsular distention, sclerosis, and erosion. Therefore, we created the ACJ cross-sectional area (ACJCSA) as a new diagnostic image parameter to assess the irregular morphologic changes of the ACJ.

AIM

To hypothesize that the ACJCSA is a new diagnostic image parameter for ACJO.

METHODS

ACJ samples were obtained from 35 patients with ACJO and 30 healthy individuals who underwent shoulder magnetic resonance (S-MR) imaging that revealed no evidence of ACJO. Oblique coronal, T2-weighted, fat-suppressed S-MR images were acquired at the ACJ level from the two groups. We measured the ACJCSA and the ACJ space width (ACJSW) at the ACJ on the S-MR images using our imaging analysis program. The ACJCSA was measured as the cross-sectional area of the ACJ. The ACJSW was measured as the narrowest point between the acromion and the clavicle.

RESULTS

The average ACJCSA was 39.88 ± 10.60 mm² in the normal group and 18.80 ± 5.13 mm² in the ACJO group. The mean ACJSW was 3.51 ± 0.58 mm in the normal group and 2.02 ± 0.48 mm in the ACJO group. ACJO individuals had significantly lower ACJCSA and ACJSW than the healthy individuals. Receiver operating characteristic curve analyses demonstrated that the most suitable ACJCSA cutoff score was 26.14 mm², with 91.4% sensitivity and 90.0% specificity.

CONCLUSION

The optimal ACJSW cutoff score was 2.37 mm, with 88.6% sensitivity and 96.7% specificity. Even though both the ACJCSA and ACJSW were significantly associated with ACJO, the ACJCSA was a more sensitive diagnostic image parameter.

Osteoid Osteoma in an Adult Wheelchair Basketball Player Mimicking Musculoskeletal Shoulder Pain: Red Flag or a Red Herring?

Osteoid osteoma (OO) is a relatively common, benign bone-forming tumour, which mainly occurs on the long tubular bones of the limbs in adolescents. Usually, the OO is classified based on its localisation. Night-time pain is the major symptom of OO, which is commonly relieved using non-steroidal anti-inflammatory drugs, while surgery is required only for those patients with severe pain or in case of failure of previous conservative treatments. Our case report describes a 56-year-old male basketball player who self-referred to our outpatient physical therapy with a shoulder pain complaint. Considering the anamnesis and the physical examination, the physical therapist referred the patient to an orthopaedic surgeon, who suggested a detailed imaging investigation. The peculiarity of this clinical case is the overlapping of two clinical presentations: the symptomatology of the OO and the concurrent mechanical disorder due to a rotator cuff tendinopathy.

Current Views of Scapular Dyskinesis and its Possible Clinical Relevance

Scapular dyskinesis is a condition that is frequently observed clinically but not often understood. Too often it is viewed as a diagnosis which is not accurate because it is a physical impairment. This misclassification of dyskinesis has resulted in literature that simultaneously supports and refutes scapular dyskinesis as a relevant clinical entity as it relates to arm function. These conflicting views have not provided clear recommendations for optimal evaluation and treatment methods. The authors' experience and scholarship related to scapular function and dysfunction support that scapular dyskinesis is an impairment that has causative factors, that a pathoanatomical approach should not be the primary focus but should be considered as part of a comprehensive examination, that a qualitative examination for determining the presence or absence of a scapular contribution to shoulder dysfunction is currently the best option widely available to clinicians, and that rehabilitation approaches should be reconsidered where enhancing motor control becomes the primary focus rather than increasing strength.

Three-dimensional kinematic evaluation of scapulohumeral rhythm after reverse shoulder arthroplasty: a systematic review and meta-analysis

Background

The movement of the arm relative to the trunk results from 3-dimensional (3D) coordinated movements of the glenohumeral (GH) and scapulothoracic (ST) joints and dictates the scapulohumeral rhythm (SHR). Alterations in SHR increase joint overload and may lead to low functional scores, pain, and failures in patients undergoing reverse total shoulder arthroplasty (RSA). The goal of this systematic review and meta-analysis was to examine 3D SHR kinematics after RSA and compare it to that of asymptomatic shoulders.

Methods

A systematic review and meta-analysis of articles in English were performed using PubMed, Embase, Cochrane Library, and SciELO. Additional studies were identified by searching bibliographies. Search terms included "Reverse shoulder arthroplasty", "3D", and "scapula". It was selected cross-sectional studies that reported SHR with 3D motion analysis systems in patients who underwent RSA and asymptomatic controls. Two authors independently performed the extraction of articles using predefined data fields, including study quality indicators.

Results

Data from four studies were included in quantitative analysis, totaling 48 shoulders with RSA and 63 asymptomatic shoulders. Pooled analyses were based on random-effects model (DerSimonian-Laird). A statistically smaller SHR ratio was observed in the RSA group than that in the control group (P < .00001), meaning a greater contribution of ST joint in relation to GH joint for arm elevation. The standardized mean difference was -1.16 (95% confidence interval: -1.64, -0.67). A sensitivity analysis with three more studies that had imputed data on control group did not change the direction of the effect. The standardized mean difference on sensitivity analysis was -0.60 (P = .03; 95% confidence interval: -1.13, -0.06). It was detected as "not important heterogeneity" within the comparison (I2: 22%). Chi-square was not statistically significant (Chi2: 3.85), and I2 was 22%. Tau2 was not zero (Tau2: 0.05). Sensitivity analysis showed an I2 of 74%, which might represent substantial heterogeneity, Chi-square was not statistically significant (Chi2: 23.01), and Tau2 was not zero (Tau2: 0.37).

Conclusion

This study found that RSA shoulders have an increased contribution of ST joint during arm elevation, compared with asymptomatic shoulders. More movement in ST joint in proportion to GH joint increases GH joint contact forces, which could lead to component loosening or other complications. Further studies should address the clinical implications of this kinematic finding.

Flexibility, Position, and Strength of the Shoulder Complex in Pediatric and Adult Amateur Tennis Athletes

CONTEXT

Understanding the musculoskeletal adaptations in the shoulder complex of varying ages of tennis athletes may suggest preventive protocols and conditioning and rehabilitation programs to this population. This study aimed to generate a bilateral descriptive profile of shoulder flexibility, scapular and clavicular position, and muscle strength in pediatric and adult amateur tennis athletes. The outcome measures were compared between groups and sides. The number and percentage of athletes "at risk" according to cutoff values for shoulder range of motion (ROM) were also analyzed.

DESIGN

Cross-sectional study.

METHODS

36 pediatric and 28 adult amateur tennis athletes were tested. Outcome measures were ROM of shoulder flexion, abduction, internal and external rotation, posterior capsule tightness, pectoralis minor index (PMI), scapular upward rotation, clavicular elevation, and strength of the external rotators, serratus anterior, and lower trapezius of the dominant/nondominant sides.

RESULTS

Pediatric athletes had greater dominant side external rotation (P = .01) and total ROM (P = .04), increased Low Flexion test (P = .01), and decreased PMI (P = .01) compared with the adults. Bilaterally, the pediatric athletes had greater dominant side external rotation ROM (P < .01) and decreased PMI (P = .002) as compared with their nondominant side, whereas the adults displayed lower values on posterior capsule tightness (P = .01) and decreased PMI (P = .02) on their dominant side compared with their nondominant side. For the remaining outcomes, no interaction effects were observed. The cutoff values for shoulder ROM showed that several athletes were "at risk" of shoulder problems.

CONCLUSION

Upper extremity adaptations at the shoulder are present in both pediatric and adult tennis athletes. These data can assist clinicians in better understanding the biomechanical adaptations in the shoulder of amateur tennis athletes in different age groups.

Ratio between 3D glenohumeral and scapulothoracic motions in individuals without shoulder pain

This study determined the ratio between glenohumeral and three-dimensional scapular motion during arm elevation and lowering in 91 individuals without shoulder pain. Scapular kinematics were assessed using an electromagnetic tracking device. Individuals performed 3 repetitions of elevation and lowering of the arm in the sagittal plane. Two-way ANOVAs (interval: 30-60°, 60-90°, 90-120° x phase: elevation and lowering) and paired t-tests were used for data analysis. For scapular internal/external rotation, lesser scapular internal rotation contribution was found during the 60-90° interval as compared to the 90-60° interval. Lesser scapular external rotation was identified in the 60-30° interval of arm lowering. The ratio was greater during arm elevation (1.89) compared to lowering (1.74) across the entire motion arc. For scapular upward rotation, greater upward rotation contribution was observed during arm elevation at the 30-60° interval, and less scapular downward rotation contribution in the final range of arm lowering. For scapular tilt, lesser scapular posterior tilt contribution during arm elevation was observed compared to arm lowering. The ratios between glenohumeral elevation/lowering and each individual scapulothoracic motion showed either differences between intervals and/or between elevation and lowering during specific intervals in healthy individuals.

Kinematics and muscle activation in subacromial pain syndrome patients and asymptomatic controls

BACKGROUND

Conflicting theories exist about the underlying cause of chronic subacromial pain in the middle-aged population. We aim to improve our understanding of kinematics and muscle activation in subacromial pain syndrome to provide insight in its pathophysiology.

METHODS

In a cross-sectional comparison of 40 patients with subacromial pain syndrome and 30 asymptomatic controls, three-dimensional shoulder kinematics and electromyography-based co-contraction in 10 shoulder muscles were independently recorded. Glenohumeral and scapulothoracic kinematics were evaluated during abduction and forward flexion. Co-contraction was expressed as an activation ratio, specifying the relative agonistic and antagonistic muscle activity in each muscle.

FINDINGS

During abduction and forward flexion, the contribution of glenohumeral motion to elevation and glenohumeral external rotation was lower in subacromial pain syndrome (at 120⁰ abduction: -9°, 95% CI -14°- -3°; and - 8°, 95% CI -13°--3°, respectively), and was compensated by more scapulothoracic motion. The pectoralis major's activation ratio was significantly lower (Z-score: -2.657, P = 0.008) and teres major's activation ratio significantly higher (Z-score: -4.088, P < 0.001) in patients with subacromial pain syndrome compared to the control group.

INTERPRETATION

Reduced glenohumeral elevation and external rotation in subacromial pain syndrome coincided with less teres major antagonistic activity during elevation. These biomechanical findings provide a scientific basis for intervention studies directed at stretching exercises to reduce glenohumeral stiffness in the treatment of subacromial pain syndrome, and teres major strengthening to improve humeral head depressor function.

Scapular Retraction under Adduction Load: An Alternative to Overhead Exercises to Activate Infraspinatus, Upper, and Lower Trapezius in Subjects with and without Shoulder Pain

Exercises for lower trapezius (LT) often use overhead positions, causing compressive forces to the subacromial space. Scapular retraction would be an alternative to activate LT muscle. The present study aimed to assess the excitation levels of infraspinatus, upper trapezius, and lower trapezius muscles during a scapular retraction exercise under progressive adduction loads in subjects with and without painful shoulder. Electromyography of infraspinatus (IS), upper trapezius (UT), and LT was recorded during scapular retraction under progressive adduction loads of 42 participants, divided into two groups: with (SP, n = 26) and without shoulder pain (nSP, n = 16). The adduction loads of 20%, 30%, 40%, and 50% of the maximal voluntary contraction (MVC) were applied using a load cell. Normalized electromyography and the ratio between UT and LT (UT:LT) were used for statistical analysis. No differences were observed between groups, but a condition effect occurred for all muscles: UT showed higher values at 50% vs. 20% of MVC (p = 0.004); LT showed higher values on 40% and 50% of MVC (p = 0.001; 0.006). Higher values for IS were noted at 40% of MVC (vs. 20% of MVC; p = 0.04) and at 50% of MVC (vs. 20% of MVC; p = 0.001, vs. 30% of MVC, p = 0.001; vs. 40% of MVC; p = 0.001). UT:LT showed lower values at 50% of MVC (vs. 20% of MVC; p = 0.001 and vs. 30% of MVC; p = 0.016). Scapular retraction with adduction loads at 40-50% is an alternative to overhead exercises aiming to activate the LT and the IS muscles. The exercise ensures higher levels of LT and IS excitation without increasing UT excitation.

Does scapular corrective taping alter periscapular muscle activity and 3-dimensional scapular kinematics? A systematic review

STUDY DESIGN

This is a systematic review.

INTRODUCTION

Scapular taping is widely used in the management of scapular dysfunction. However, its effects on the scapular kinematics and the electromyography (EMG) activity of the periscapular muscles are not clear.

PURPOSE OF THE STUDY

The purpose of the study was to systematically review the current literature to examine whether scapular corrective taping alters the EMG activity of the periscapular muscles and the 3-dimensional scapular kinematics.

METHOD

MEDLINE and Web of Science databases were searched using specific mesh terms up to April 2018. A hand search was also conducted on the reference list of the included articles. A total of 157 studies were identified, and they were further analyzed for the eligibility to the systematic review. Studies that investigated the effects of scapular corrective taping on the EMG activity of the periscapular muscles and on the 3-dimensional scapular kinematics on patients with shoulder problems or asymptomatic subjects were eligible for the systematic review. The Cochrane Effective Practice and Organization of Care criteria were modified and used for the risk-of-bias assessment.

RESULTS

Eleven articles met the inclusion criteria and were included in the systematic review. Five studies investigated the effects of corrective taping on the scapular kinematics and 8 studies reported the effects of corrective taping on the EMG activity of the periscapular muscles. There was an agreement among the studies that scapular upward rotation is increased with the corrective taping, while there are inconsistent results concerning the scapular external rotation and posterior tilt. In addition, studies mostly reported that corrective taping decreases the activity of the upper trapezius, while it has conflicting effects on the activity patterns of other periscapular muscles.

DISCUSSION

Scapular corrective taping was found to increase the scapular upward rotation; however, its effects on scapular external rotation and posterior tilt are controversial. It was also found that corrective taping might decrease the EMG activity of the upper trapezius, while it had no effects on the activity of lower trapezius, and its effects on other periscapular muscles were controversial.

CONCLUSION

The results of the studies indicated that scapular corrective taping might alter the 3-dimensional scapular kinematics, while there are controversies about the effects of corrective taping on the EMG activity of the periscapular muscles. Further studies are needed to clarify the conflicts.

Analysis of the Sagittal Motion Posture of the Acromioclavicular Joint Using Image Registration and Axial Angle Representation

Objective

This study aimed to directly and accurately measure the range of motion of the acromioclavicular joint through 3D reconstruction and image registration.

Methods

Thirteen healthy volunteers participated in the study. Computerized tomography (CT) was used to measure the acromioclavicular joint in four different motion poses. The images were integrated using reconstruction and registration technology, and the rotation angle range of the acromioclavicular joint was measured using 3D reconstruction. The measurements were expressed by axial angle representation. The dominant and the non-dominant sides were compared, and the difference in the axial angle of the acromioclavicular joint was compared in different postures.

Results

The difference between the dominant and non-dominant sides in acromioclavicular motion was not significant. In the sagittal motion of the upper limb, the rotation angle of the acromioclavicular joint was greatest in a resting horizontal position, with an average of 26.1°. In this position, 34.6% of flexion and extension movements of the upper limb were completed by the acromioclavicular joint, which was the highest level of engagement. The rotation angle was lowest in the resting posteroinferior position, with an average of 8.2°. In this position, 24.9% of the flexion and extension movements of the upper limb were completed by the acromioclavicular joint.

Conclusion

Combining 3D reconstruction and image registration is a direct and accurate method of measuring the motion of the acromioclavicular joint. The rotational motions of the acromioclavicular joint are bilaterally symmetrical and can be used as a reference for comparative study. The maximum range of motion of the acromioclavicular joint during rotation was found in the resting horizontal position. The clinical examination and post-treatment evaluation of the acromioclavicular joint’s rotation function can therefore be targeted in this range.

Evaluation of the inter and intraobserver reproducibility of the GRASP method: a goniometric method to measure the isolated glenohumeral range of motion in the shoulder joint

Purpose

To evaluate the intra and interobserver reproducibility of a new goniometric method for evaluating the isolated passive range of motion of the glenohumeral joint in an outpatient setting.

Methods

This is a prospective observational study on healthy subjects. The Glenohumeral ROM Assessment with Scapular Pinch (GRASP) method is a new method for assessing the isolated range of motion (ROM) of the glenohumeral joint (GH) by a single examiner with a clinical goniometer. It measures the isolated glenohumeral passive abduction (GH-AB), passive external rotation (GH-ER) and internal rotation (GH-IR) with the arm at 45º of abduction.

These three GH ROM parameters were measured in both shoulders of 30 healthy volunteers (15 males/15 females, mean age:41.6[SD = 10.3] years). The full shoulder passive abduction, passive external rotation and internal rotation 45º of abduction were measured by the same examiners with a goniometer for comparison. One examiner made two evaluations and a second examiner made a third one. The primary outcome was the intra- and interobserver reproducibility of the measurements assessed with intraclass correlation coefficients (ICC) and the Bland–Altman plot.

Results

The intra-observer ICC for isolated glenohumeral ROM were: 0.84 ± 0.07 for GH-ABD, 0.63 ± 0.09 for GH-ER, and 0.61 ± 0.14 for GH-IR. The inter-observer ICC for isolated glenohumeral ROM were: 0.86 ± 0.06 for GH-ABD, 0.68 ± 0.12 for GH-ER, and 0.62 ± 0.14 for GH-IR. These results were similar to those obtained for full shoulder ROM assessment with a goniometer.

Conclusion

The GRASP method is reproducible for quick assessment of isolated glenohumeral ROM.

Level of evidence

III

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-021-00352-z.

Comparison of specific and non-specific treatment approaches for individuals with posterior capsule tightness and shoulder impingement symptoms: A randomized controlled trial

BACKGROUND

Posterior capsule tightness (PCT) is associated with shoulder pain and altered shoulder kinematics, range of motion (ROM), external rotation (ER) strength, and pain sensitization.

OBJECTIVE

To assess the effects of two interventions on shoulder kinematics, Shoulder Pain and Disability Index (SPADI) scores, ROM, strength, and pressure pain threshold (PPT) in individuals with PCT and shoulder impingement symptoms.

METHODS

In this prospectively registered randomized controlled trial 59 individuals were randomized to either an Experimental Intervention Group (EIG, n=31) or a Control Intervention Group (CIG, n=28). The low flexion (LF) test was used to determine the presence of PCT. Shoulder kinematics, SPADI scores, internal rotation (IR) and ER ROM, ER strength, and PPT were measured pre- and post-treatment. Those in the EIG received an intervention specific to pain and PCT and those in the CIG received a non-specific intervention, both 4 weeks in duration.

RESULTS

Individuals in the EIG demonstrated more scapular upward rotation (P=.03; mean difference (MD)=3.3°; 95% Confidence Interval (CI)=1.3°, 4.9°) and improved value on the LF test (P=.02; MD=4.6°; 95%CI=0.7°, 8.6°) than those in the CIG after treatment. Both groups presented less anterior (P<.01; MD=-0.7mm; 95%CI=-1.3mm, -0.2mm) and superior (P<.01; MD=-0.5mm; 95%CI=-0.9mm, -0.2mm) humeral translations, decreased SPADI score (P<.01; MD=-23.6; 95%CI=-28.7, -18.4), increased IR ROM (P<.01; MD=4.6°; 95%CI=1.8°, 7.8°) and PPTs for upper trapezius (P<.01; MD=60.1kPa; 95%CI=29.3kPa, 90.9kPa), infraspinatus (P=.04; MD=47.3kPa; 95%CI=2.1kPa, 92.5kPa), supraspinatus (P<.01; MD=63.7kPa; 95%CI=29.6kPa, 97.9kPa), and deltoid (P<.01; MD=40.9kPa; 95%CI=12.3kPa, 69.4kPa) after treatment.

CONCLUSION

The experimental intervention was more effective at improving PCT as measured through changes in the LF test. No benefit of the specific approach over the non-specific intervention was noted for the remaining variables.

Effect of conscious abdominal contraction on the activation of periscapular muscles in individuals with subacromial pain syndrome

BACKGROUND

Synergism between shoulder and trunk muscles seems to be effective to increase periscapular muscle activation in asymptomatic subjects. The influence of conscious contraction of the abdominal muscles has not yet been studied in non-athlete subjects with pain. The study aimed to investigate the effect of the instruction for conscious activation of the abdominal muscles on the activity of the scapulothoracic muscles during shoulder exercises in subjects with subacromial pain syndrome.

METHOD

Thirty subjects with unilateral pain (mean age 52 ± 11 years) participated in this study. Three isometric and five dynamic exercises for the scapulothoracic muscles were assessed. The group without instruction just repeated the exercises, while the instruction group was evaluated before and after conscious abdominal training. The linear mixed model analysis was used to compare the muscle activation between groups.

FINDINGS

Differences between groups after the conscious abdominal contraction for activation of middle and lower trapezius on the symptomatic side in the "Full can"(p = 0.03; effect size:0.92 middle trapezius); (p = 0.02; effect size:0.96 lower trapezius) and "Knee Push" (p = 0.01; effect size:0.75 lower trapezius). For asymptomatic side, the exercises "External Rotation Kneeling" (p = 0.04; effect size: 0.81 lower trapezius); (p = 0.00; effect size: 2.09 serratus anterior), "Knee Push" (p = 0.04; effect size:1.24 serratus anterior) and "Wall Slide" (p = 0.01; effect size: 1.03 serratus anterior).

INTERPRETATION

Conscious contraction of the abdominal muscle immediately alter the activation of the serratus anterior muscle during closed kinetic chain exercises on the asymptomatic side and increased activation of trapezius on the symptomatic side during shoulder open kinetic chain exercise.

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

The shoulder is one of the human body's most complex joint systems, with motion occurring through the coordinated actions of four individual joints, multiple ligaments, and approximately 20 muscles. Unfortunately, shoulder pathologies (e.g., rotator cuff tears, joint dislocations, arthritis) are common, resulting in substantial pain, disability, and decreased quality of life. The specific etiology for many of these pathologic conditions is not fully understood, but it is generally accepted that shoulder pathology is often associated with altered joint motion. Unfortunately, measuring shoulder motion with the necessary level of accuracy to investigate motion-based hypotheses is not trivial. However, radiographic-based motion measurement techniques have provided the advancement necessary to investigate motion-based hypotheses and provide a mechanistic understanding of shoulder function. Thus, the purpose of this article is to describe the approaches for measuring shoulder motion using a custom biplanar videoradiography system. The specific objectives of this article are to describe the protocols to acquire biplanar videoradiographic images of the shoulder complex, acquire CT scans, develop 3D bone models, locate anatomical landmarks, track the position and orientation of the humerus, scapula, and torso from the biplanar radiographic images, and calculate the kinematic outcome measures. In addition, the article will describe special considerations unique to the shoulder when measuring joint kinematics using this approach.

Scapular movement training versus standardized exercises for individuals with chronic shoulder pain: protocol for a randomized controlled trial

BACKGROUND

Scapular focused exercise interventions are frequently used to treat individuals with shoulder pain. However, evidence for changes in scapular motion after intervention is limited.

OBJECTIVE

To compare the effects of scapular movement training versus standardized exercises for individuals with shoulder pain.

METHODS

This will be a single-blinded randomized controlled trial. Sixty-four individuals with shoulder pain for at least 3 months, scapular dyskinesis, and a positive scapular assistance test will be randomly allocated to one of two groups: Scapular Movement Training (group 1) and Standardized Exercises (group 2). Group 1 will receive education about scapular position and movement, and be trained to modify the scapular movement pattern. Group 2 will perform stretching and strengthening exercises. Both groups will be treated twice a week for eight weeks. Three-dimensional scapular kinematics and muscle activity of the serratus anterior and upper, middle, and lower trapezius during elevation and lowering of the arm will be assessed at baseline and after 8 weeks of treatment. Pain intensity, function, fear avoidance beliefs, and kinesiophobia will be assessed at baseline and after 4 and 8 weeks of treatment, and 4 weeks after the end of treatment.

CONCLUSIONS

The results of this study may contribute to a better understanding of the efficacy of scapular focused treatments for individuals with shoulder pain.

CLINICAL TRIAL REGISTRATION

NCT03528499.

An unusual presentation of acute myocardial infarction in physiotherapy direct access: findings from a case report

BACKGROUND

Shoulder pain (SP) may originate from both musculoskeletal and visceral conditions. Physiotherapists (PT) may encounter patients with life-threatening pathologies that mimic musculoskeletal pain such as Acute Myocardial Infarction (AMI). A trained PT should be able to distinguish between signs and symptoms of musculoskeletal or visceral origin aimed at performing proper medical referral.

CASE PRESENTATION

A 46-y-old male with acute SP lasting from a week was diagnosed with right painful musculoskeletal shoulder syndrome, in two successive examinations by the emergency department physicians. However, after having experienced a shift of the pain on the left side, the patient presented to a PT. The PT recognized the signs and symptoms of visceral pain and referred him to the general practitioner, which identified a cardiac disease. The final diagnosis was acute myocardial infarction.

CONCLUSION

This case report highlights the importance of a thorough patient screening examination, especially for patients treated in an outpatient setting, which allow distinguishing between signs and symptoms of musculoskeletal from visceral diseases.