The association of scapular kinematics and glenohumeral joint pathologies

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.

Scapula-Focused Exercises With or Without Biofeedback and Corticospinal Excitability in Recreational Overhead Athletes With Shoulder Impingement

CONTEXT

Individuals with shoulder impingement syndrome (SIS) exhibit changes in corticospinal excitability, scapular kinematics, and scapular muscle-activation patterns. To restore the scapular kinematics and muscle-activation patterns in individuals with SIS, treatment protocols usually include scapula-focused exercises, such as scapular-orientation and strength training.

OBJECTIVE

To investigate whether scapular-orientation and strength training can reverse the altered corticospinal excitability of recreational overhead athletes with SIS.

DESIGN

Randomized controlled clinical trial.

SETTING

University laboratory.

PATIENTS OR OTHER PARTICIPANTS

Forty-one recreational overhead athletes with SIS: 20 in the scapular-orientation group (age = 26.45 ± 4.13 years, height = 171.85 ± 7.88 cm, mass = 66.70 ± 10.68 kg) and 21 in the strengthening group (age = 26.43 ± 5.55 years, height = 171.62 ± 5.87 cm, mass = 68.67 ± 10.18 kg).

INTERVENTION(S)

Both groups performed a 30-minute training protocol consisting of 3 exercises to strengthen the lower trapezius (LT) and serratus anterior muscles without overactivating the upper trapezius muscles. Participants in the scapular-orientation group were instructed to consciously activate their scapular muscles with electromyographic biofeedback and cues, whereas the strengthening group did not receive biofeedback or cues for scapular motion.

MAIN OUTCOME MEASURE(S)

Corticospinal excitability was assessed using transcranial magnetic stimulation. Scapular kinematics and muscle activation during arm elevation were also measured.

RESULTS

After training, both groups demonstrated an increase in motor-evoked potentials in the LT (P = .004) and increases in scapular upward rotation (P = .03), LT activation (P < .001), and serratus anterior activation (P < .001) during arm elevation. Moreover, the scapular-orientation group showed higher LT activation levels during arm elevation after training than the strengthening group (P = .03).

CONCLUSIONS

With or without biofeedback and cues, scapula-focused exercises improved scapular control and increased corticospinal excitability. Adding biofeedback and cues for scapular control during exercise helped facilitate greater LT activation, so feedback and cues are recommended during scapula-focused training.

Clavicle fractures do not increase the occurrence of later subacromial pain syndrome. A registry-based case-control study with 15-25 years of follow-up of 131.838 persons from the Danish National Patient Register

Background

A clavicle fracture often changes the mechanical axes of the shoulder girdle due to displacement and shortening, potentially leading to scapular protraction and decreased subacromial space. If protraction of the scapula is a major risk factor for developing subacromial pain syndrome (SAPS), a previous clavicle fracture could increase the risk of later SAPS. The purpose of this study was to investigate if a previous clavicle fracture correlates with a higher occurrence or earlier diagnosis of SAPS.

Methods

In this retrospective case-control study with data from the Danish National Patient Register, all persons aged 18-60 years, with any hospital contact due to a clavicle fracture (DS420) between January 1, 1996, and December 31, 2005, were identified as cases. For each case, five controls, matched on age and sex, were identified. Primary outcome was the first hospital contact with a SAPS diagnosis (DM751-755) registered more than 180 days following the fracture. Follow-up was until November 01, 2021.

Results

21.973 cases and 109.865 controls were included. The incidence of clavicle fractures was 76 fractures per 100.000 persons per year. Twenty-three percent were female. 1.640 (7.46%) cases and 8.072 (7.35%) controls received a SAPS diagnosis within the following 15-25 years, demonstrating no significant difference in the occurrence of SAPS (P = .56). The mean time from fracture to SAPS diagnosis was shorter for cases compared to controls (4040 vs. 4442 days, P < .001), and cases were slightly younger when receiving the diagnosis (51.3 vs. 53.6 years, P < .001). 1614 cases underwent surgical fixation. This subgroup had a statistically significant higher occurrence of later SAPS diagnosis (205 cases, 13%, P < .001).

Conclusions

Persons with a previous clavicle fracture did not have an increased occurrence of receiving a SAPS diagnosis compared to matched controls. However, the diagnosis was given 1-2 years earlier for people with a previous fracture. Based on these findings, no strong argument for protraction of the scapula as a major risk factor for the development of SAPS was found.

Neuromuscular electrical stimulation of humeral adductors in subjects with rotator cuff tear

INTRODUCTION

In symptomatic patients with rotator cuff tear, MRI and radiographic studies have ascribed the pain symptom to insufficient humeral head depression during arm elevations. The arm adductors such as the teres major and pectoralis major may contribute to depression of the humerus head during arm elevations. Researchers have demonstrated that neuromuscular electrical stimulation (NMES) of the serratus anterior and lower trapezius can control scapular motions and improve acromiohumeral distance. It is unknown, however, if adductor neuromuscular training could help patients with rotator cuff tear.

MATERIALS AND METHODS

A cross-sectional study of NMES of the teres major and pectoralis major was conducted on 30 symptomatic subjects with rotator cuff tear. We measured the acromiohumeral distance by ultrasonography and scapular kinematics during arm elevation with a three-dimensional motion tracking system.

RESULTS

The acromiohumeral distance significantly increased during NMES of the teres major (0.73 mm, p < 0.001). However, the distance significantly decreased with NMES of the pectoralis major (0.78 mm, p < 0.001). Additionally, scapular upward rotation was greater during NMES of the teres major than during NMES of the pectoralis major (3.4°, p < 0.001). Scapular external rotation decreased significantly more during NMES of the pectoralis major than during NMES of the teres major (1.6°, p = 0.003).

CONCLUSIONS

NMES of the teres major can increase acromiohumeral distance and scapular upward rotation during arm elevation. However, the decreased upward and external rotation of the scapula during arm elevation with NMES of the pectoralis major may be associated with subacromial impingement.

Effectiveness of specific scapular therapeutic exercises in patients with shoulder pain: a systematic review with meta-analysis

Background

Therapeutic exercise has been considered a useful tool to rehabilitate shoulder pain, namely through its influence on scapular dynamics. Accordingly, the effectiveness of scapular therapeutic exercise needs to be explored. The present study aims to evaluate the effectiveness of scapular therapeutic exercises in shoulder pain and to identify the most effective exercise type (focal or multijoint) and ways of delivering them (as dose and progression).

Methods

Search was conducted at EMBASE, Cochrane Library, MEDLINE via PubMed, Web of Science, PEDro (Physiotherapy Evidence Database), and trial registration databases. The meta-analysis considered randomized controlled/crossover trials that compared the effect of scapular exercises against other types of intervention in the shoulder pain, shoulder function, scapular motion, and/or muscular activity. The risk of bias was assessed through the PEDro scale.

Results

From the 8318 records identified, 8 (high to low risk of bias- scoring from 4 to 8 on the PEDro scale) were included. The overall data, before sensitivity analysis, indicated that the scapular therapeutic exercises are: a) more effective than comparators in improving shoulder function (standardized mean difference [SMD] = 0.52 [95% Cl: 0.05, 0.99], P = .03, I2 = 76%); and b) as effective as comparators in reducing shoulder pain (SMD = 0.32 [95% Cl: -0.09, 0.73], P = .13, I2 = 70%). Subgroup analysis revealed that scapular exercises are more effective in improving shoulder function when the program duration is equal to or higher than 6 weeks (SMD = 0.43 [95% Cl: 0.09, 0.76] P = .01, I2 = 21%) and/or when the maximum number of exercise repetitions per session is lower than 30 (SMD = 0.79 [95% Cl: 0.15, 1.42], P = .01, I2 = 77%). Only 1 study considered scapular motion as an outcome measure, revealing therapeutic exercise effectiveness to improve scapular range of motion.

Conclusions

Intervention programs involving scapular therapeutic exercises are effective in improving shoulder function, presenting benefits when performed for 6 or more weeks and/or when used up to a maximum of 30 repetitions per exercise, per session.

Comparison of glenohumeral and scapulothoracic kinematics between fastballs and curveballs during baseball pitching

Shoulder injuries are common in baseball pitchers and primarily involve the glenohumeral joint. Past analyses have examined shoulder biomechanics during different pitch types simply as the motion of the upper arm relative to the thorax. In this study, glenohumeral and scapulothoracic kinematics were compared between fastballs and curveballs at key timepoints throughout a pitch. Upper extremity kinematics of thirteen collegiate pitchers were collected during fastball and curveball pitches with motion capture. A linear model approach was utilised to estimate scapular kinematics based on measurable humerothoracic motion. Glenohumeral kinematics were computed from the scapular and humeral motion data. Comparisons of scapulothoracic and glenohumeral kinematic variables at times of maximum glenohumeral external rotation, ball release, and maximum glenohumeral internal rotation between pitch types were made using paired t-tests with Benjamini-Hochberg corrections. There were no significant differences in glenohumeral kinematics. Fastballs elicited significantly less scapulothoracic internal rotation and more posterior tilt at maximum glenohumeral external rotation. Fastballs produced significantly less scapulothoracic internal rotation and anterior tilt at maximum glenohumeral internal rotation. This study provides further evidence that risk of injury to the glenohumeral joint may be consistent between fastballs and curveballs and offers insights into subtle differences in scapular kinematics between pitch types.

Differences in Osseous Shoulder Morphology, Scapulothoracic Orientation, and Muscle Volume in Patients With Constitutional Static Posterior Shoulder Instability (Type C1) Compared With Healthy Controls

BACKGROUND

Constitutional static posterior humeral decentering (type C1 according to ABC Classification) has been recognized as a pre-osteoarthritic deformity that may lead to early-onset posterior decentering osteoarthritis at a young age. Therefore, it is important to identify possible associations of this pathologic shoulder condition to find more effective treatment options.

PURPOSE

To perform a comprehensive analysis of all parameters reported to be associated with a C1 shoulder-including the osseous shoulder morphology, scapulothoracic orientation, and the muscle volume of the shoulder girdle in a single patient cohort.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A retrospective, comparative study was conducted analyzing 17 C1 shoulders in 10 patients who underwent magnetic resonance imaging (MRI) with the complete depiction of the trunk from the base of the skull to the iliac crest, including both humeri. The mean age of the patients was 33.5 years, and all patients were men. To measure and compare the osseous shoulder morphology (glenoid version, glenoid offset, humeral torsion, anterior acromial coverage, posterior acromial coverage, posterior acromial height, and posterior acromial tilt) and scapulothoracic orientation (scapular protraction, scapular internal rotation, scapular upward rotation, scapular translation, scapular tilt, and thoracic kyphosis), these patients were matched 1 to 4 according their age, sex, and affected side with shoulder-healthy patients who had received positron emission tomography (PET)-computed tomography. To measure and compare the muscle volume of the shoulder girdle (subscapularis, infraspinatus/teres minor, supraspinatus, trapezius, deltoid, latissimus dorsi/teres major, pectoralis major, and pectoralis minor), patients were matched 1 to 2 with patients who had received PET-MRI. Patients with visible pathologies of the upper extremities were excluded.

RESULTS

The C1 group had a significantly higher glenoid retroversion, increased anterior glenoid offset, reduced humeral retrotorsion, increased anterior acromial coverage, reduced posterior acromial coverage, increased posterior acromial height, and increased posterior acromial tilt compared with controls (P < .05). Decreased humeral retrotorsion showed significant correlation with higher glenoid retroversion (r = -0.742; P < .001) and higher anterior glenoid offset (r = -0.757; P < .001). Significant differences were found regarding less scapular upward rotation, less scapular tilt, and less thoracic kyphosis in the C1 group (P < .05). The muscle volume of the trapezius and deltoid was significantly higher in the C1 group (P < .05).

CONCLUSION

Patients with C1 shoulders differ from healthy controls regarding osseous scapular and humeral morphology, scapulothoracic orientation, and shoulder girdle muscle distribution. These differences may be crucial in understanding the delicate balance of glenohumeral centering.

Scapular motion during shoulder joint extension movement

A few reports on scapular motion during shoulder joint extension exist. Understanding the normal motion of shoulder joint extension may be useful in evaluating and treating patients with diminished or minimal shoulder joint extension. Therefore, this study aimed to identify scapular motion during shoulder joint extension movement in a sitting position. Shoulder joint extension movement in the sitting position were measured in 22 healthy adults (age, 25.8 ± 2.7 years). Shoulder joint extension, scapular upward rotation, anterior tilt, external rotation angles, and the acromion position were investigated using a three-dimensional motion analyzer. The difference from each value of 10° to 50° shoulder joint extension to each value of 0° shoulder joint extension were checked. The results were compared using multiple comparison method. In most participants, the scapula tilted posteriorly up to 30° of the shoulder joint extension and anteriorly after 30°. Scapular upward and external rotation continued to increase with shoulder extension. Furthermore, the acromion was displaced upward and backward. Thus, scapular posterior tilt is necessary for shoulder joint extension during the initial movement, followed by anterior tilt. The acromion may have been displaced posteriorly because of clavicular retraction, causing the scapula to tilt posteriorly. After 30° of shoulder joint extension, the scapular anterior tilt may have prevailed over the scapular posterior tilt.

Crossed raised arm position improves the flow of contrast medium in torso contrast-enhanced computed Tomography

INTRODUCTION

This retrospective cohort study examined the effects of the crossed raised arm (CRA) position in contrast-enhanced computed tomography (CECT) on contrast medium influx and image quality relative to the conventional position.

METHODS

Contrast medium influx into the collateral veins on CECT images was evaluated in 92 participants. The CT values of the pulmonary artery, descending aorta, and spleen were obtained in both positions and compared. Anatomical changes in the diameters and area of the subclavian vein and costoclavicular distance were also analyzed.

RESULTS

Contras 27 and 6 patients in the conventional and CRA positions, respectively. The influx risk ratio in the CRA position versus that in the conventional position was 0.22 (95% confidence interval, 0.10-0.51). Elevations in the median CT value of the pulmonary artery, descending aorta, and spleen in the CRA position were 7.0% (p < .001), 7.4% (p < .001), and 9.8% (p < .001), respectively. Enlargements in the major and minor diameters of the subclavian vein, subclavian vein area, and costoclavicular distance in the CRA position versus those in the conventional position were 19.3% (p < .001), 28.1% (p < .001), 53.6%, and 30.0% (p < .001), respectively.

CONCLUSION

The CRA position effectively prevented contrast medium influx into the collateral veins due to SVS and increased CT values in the target organs in CECT. The diameters and area of the subclavian vein and costoclavicular distance were enlarged at the thoracic outlet, which improved the flow of the contrast medium into the targeted organs.

IMPLICATIONS FOR PRACTICE

The CRA position can contribute to obtaining better CECT images during common clinical assessments at no additional cost.

Effect of scapular stabilization exercises on subacromial pain (impingement) syndrome: a systematic review and meta-analysis of randomized controlled trials

Objective

To evaluate the effectiveness of scapular stabilization exercises (SSE) in the treatment of subacromial pain syndrome (SAPS).

Methods

Clinical randomized controlled trials (RCTs) on SSE in the treatment of SAPS were searched electronically in PubMed, Science Direct, Cochrane Central Register of Controlled Trials (CENTRAL), EBSCOhost, Physiotherapy Evidence Database (PEDro), Web of Science, and other databases from 2000 to 2022, supplemented by manual search. Final RCTs were selected based on inclusion and exclusion criteria, and the Physiotherapy Evidence Database scale was used to evaluate the methodological quality of the study. A meta-analysis was conducted on data using the RevMan5.4 software.

Results

Eight RCTs involving 387 participants were included. The meta-analysis showed that the experimental group (SSE) had greater improvements in the Visual Analog Scale score [Weighted Mean Difference (WMD) = -0.94, 95% CI (-1.23, -0.65), p < 0.001] and the Shoulder Pain and Disability Index score [WMD = -10.10, 95% CI (-18.87, -1.33), p = 0.02] than the control group (conventional physical therapy). However, range of motion (ROM) was not found to be greater in the experimental group than in the control group.

Conclusion

Existing evidence moderately supports the efficacy of SSE for reducing pain and improving function in SAPS, without significant improvement in ROM. Future research should focus on larger, high-quality, standardized protocols to better understand SSE's effects across diverse SAPS populations, treatment, and outcome measures.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=307437, CRD42022307437.

Scapular muscle dynamic stiffness of asymptomatic subjects and subjects with chronic shoulder pain, at rest and isometric contraction conditions

Muscle stiffness had a crucial role in joint stability, particularly, at the shoulder complex. Although changes in upper trapezius muscle stiffness have been described for shoulder pain, contradictory findings have been obtained. Also, existing data regarding scapular muscles are, majorly, about trapezius. Myotonometry is a method used to assess stiffness; however, the reliability values of scapular muscle stiffness through this method have not been assessed in shoulder pain conditions. The present study aims to compare scapular muscles' stiffness (trapezius, serratus anterior, and levator scapulae) between subjects with and without chronic shoulder pain and to evaluate the related test-retest reliability. Twenty-two symptomatic and twenty-two asymptomatic subjects participated in a cross-sectional study. The dynamic muscular stiffness of scapular muscles, at rest and during an isometric contraction, was measured bilaterally with myotonometry, in two moments. The differences in bilateral averaged values between symptomatic and asymptomatic subjects and the effect of the group (group presenting pain in the dominant or non-dominant side, and asymptomatic group) and of the limb (unilateral painful or asymptomatic limb, and bilateral asymptomatic limbs) were investigated. Test-retest intra-rater reliability was determined. An effect of the group was observed at rest, for middle trapezius stiffness, and during contraction, for middle and lower trapezius stiffness. For middle trapezius, increased values were observed in the group presenting pain in non-dominant side comparing to both groups or to group presenting pain in dominant side. The intraclass correlation coefficient, majorly, ranged between 0.775 and 0.989. Participants with pain in the non-dominant side presented an increased middle trapezius' stiffness. Globally, high reliability was observed for scapular muscles dynamic stiffness.

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.

Immediate effects of myofascial release to the pectoral fascia on posture, range of motion, and muscle excitation: a crossover randomized clinical trial

CONTEXT

Forward shoulder posture (FSP) is a risk factor for shoulder pathology. Manual therapists often use myofascial release (MFR) to elongate restricted pectoral fascia to reduce FSP and improve shoulder function; however, the effects of this treatment approach remain anecdotal.

OBJECTIVE

Determine the acute effects of 4-min of MFR, compared to a soft-touch control (CON), to the pectoral fascia on: 1) FSP, 2) shoulder horizontal abduction ROM (HA-ROM), and 3) muscle excitation of the trapezius (upper, middle, lower [UT, MT, LT]) and pectoralis major (PEC).

METHODS

Fifty-nine right-handed participants (27 ± 9 years, 30 female) with FSP, but otherwise asymptomatic shoulders participated in a randomized crossover clinical trial by attending two experimental sessions: one MFR and one CON treatment, each administered by a Registered Massage Therapist. FSP, HA-ROM, and muscle excitation during a reaching task, were measured before and after each treatment.

RESULTS

There was a significant interaction between treatment and time for FSP (p = .018, ηp = .093) with FSP decreasing from PRE MFR (128 ± 19 mm) to POST MFR (123 ± 19 mm; p < .001, ηp = .420) and PRE CON (126 ± 19 mm) to POST CON (124 ± 18 mm; p < .001, ηp = .191) interventions. There were no significant differences in HA-ROM or muscle excitation.

CONCLUSION

Four minutes of MFR or CON to the pectoral fascia acutely reduces FSP.

Rotator cuff tears

Rotator cuff tears are the most common upper extremity condition seen by primary care and orthopaedic surgeons, with a spectrum ranging from tendinopathy to full-thickness tears with arthritic change. Some tears are traumatic, but most rotator cuff problems are degenerative. Not all tears are symptomatic and not all progress, and many patients in whom tears become more extensive do not experience symptom worsening. Hence, a standard algorithm for managing patients is challenging. The pathophysiology of rotator cuff tears is complex and encompasses an interplay between the tendon, bone and muscle. Rotator cuff tears begin as degenerative changes within the tendon, with matrix disorganization and inflammatory changes. Subsequently, tears progress to partial-thickness and then full-thickness tears. Muscle quality, as evidenced by the overall size of the muscle and intramuscular fatty infiltration, also influences symptoms, tear progression and the outcomes of surgery. Treatment depends primarily on symptoms, with non-operative management sufficient for most patients with rotator cuff problems. Modern arthroscopic repair techniques have improved recovery, but outcomes are still limited by a lack of understanding of how to improve tendon to bone healing in many patients.

Improved joint function when reaching behind the back is associated with patient reported outcomes in individuals with rotator cuff tears following exercise therapy

BACKGROUND

Reaching behind the back is painful for individuals with rotator cuff tears. The objectives of the study were to determine changes in glenohumeral kinematics when reaching behind the back, passive range of motion (RoM), patient reported outcomes and the relationships between kinematics and patient reported outcomes following exercise therapy.

METHODS

Eighty-four individuals with symptomatic isolated supraspinatus tears were recruited for this prospective observational study. Glenohumeral kinematics were measured using biplane radiography during a reaching behind the back movement. Passive glenohumeral internal rotation and patient reported outcome measures were collected. Depending on data normality, appropriate tests were utilized to determine changes in variables. Spearman's correlations were utilized for associations, and Stuart-Maxwell tests for changes in distributions.

FINDINGS

Maximum active glenohumeral internal rotation increased by 3.2° (P = 0.001), contact path length decreased by 5.5% glenoid size (P = 0.022), passive glenohumeral internal rotation RoM increased by 4.9° (P = 0.001), and Western Ontario Rotator Cuff Index and American Shoulder and Elbow Surgeons scores increased by 29.8 and 21.1 (P = 0.001), respectively. Changes in Western Ontario Rotator Cuff Index scores positively associated with changes in maximum active glenohumeral internal rotation and negatively associated with changes in contact path lengths (P = 0.008 and P = 0.006, respectively).

INTERPRETATION

The reaching behind the back movement was useful in elucidating in-vivo mechanistic changes associated with patient reported outcomes. Glenohumeral joint function and patient reported outcomes improved, where changes in Western Ontario Rotator Cuff Index scores were associated with kinematics. These findings inform clinicians of functional changes following exercise therapy and new targetable treatment factors.

Do Sex and Age Influence Scapular and Thoracohumeral Kinematics During a Functional Task Protocol?

There is mixed evidence on the role that biological sex plays in shoulder biomechanics despite known differences in musculoskeletal disorder prevalence between males and females. Additionally, advancing age may contribute to shoulder kinematic changes. The purpose of this study was to determine if sex and age influenced scapular and thoracohumeral kinematics during a range of functional tasks. Sixty healthy participants aged 19-63 years (30 males; 30 females) completed a functional task protocol while their upper limb motion was recorded. Scapular and humeral angles were calculated and compared with multiple linear regressions to assess the interaction effects of sex and age. Shoulder kinematics were not different between sex and age groups for many of the functional tasks. However, females had lower humeral external rotation in the overhead lift task (15°, P < .001), and less scapular anterior tilt angles in the forward transfer task (6°, P < .001) than males. Age was positively associated with humeral elevation (R2 = .330, P < .001) and scapular rotation (R2 = .299, P < .001) in the Wash Axilla task. There exist some kinematic differences between sex and with advancing age for select functional tasks, which should be considered for musculoskeletal disorder development.

Establishing Normative Values for Acromion Anatomy: A Comprehensive MRI-Based Study in a Healthy Population of 996 Participants

Shoulder pain is a common issue often linked to conditions such as subacromial impingement or rotator cuff lesions. The role of the acromion in these symptoms remains a subject of debate. This study aims to establish standardized values for commonly used acromion dimensions based on whole-body MRI scans of a large and healthy population and to investigate potential correlations between acromion shape and influencing factors such as sex, age, BMI, dominant hand, and shoulder pain. The study used whole-body MRI scans from the Study of Health in Pomerania, a German population-based study. Acromion index, acromion tilt, and acromion slope were measured. Interrater variability was tested with two independent, trained viewers on 100 MRI sequences before actual measurements started. Descriptive statistics and logistic regression were used to evaluate the results. We could define reference values based on a shoulder-healthy population for each acromion parameter within the 2.5 to 97.5 percentile. No significant differences were found in acromion slope, tilt, and index between male and female participants. No significant correlations were observed between acromion morphology and anthropometric parameters such as height, weight, or BMI. No significant differences were observed in acromion parameters between dominant and non-dominant hands or stated pain intensity. This study provides valuable reference values for acromion-related parameters, offering insight into the anatomy of a healthy shoulder. The findings indicate no significant differences in acromion morphology based on sex, weight, BMI, or dominant hand. Further research is necessary to ascertain the clinical implications of these reference values. The establishment of standardized reference values opens new possibilities for enhancing clinical decision making regarding surgical interventions, such as acromioplasty.

Individuals with rotator cuff tears unsuccessfully treated with exercise therapy have less inferiorly oriented net muscle forces during scapular plane abduction

Exercise therapy for individuals with rotator cuff tears fails in approximately 25.0 % of cases. One reason for failure of exercise therapy may be the inability to strengthen and balance the muscle forces crossing the glenohumeral joint that act to center the humeral head on the glenoid. The objective of the current study was to compare the magnitude and orientation of the net muscle force pre- and post-exercise therapy between subjects successfully and unsuccessfully (e.g. eventually underwent surgery) treated with a 12-week individualized exercise therapy program. Twelve computational musculoskeletal models (n = 6 successful, n = 6 unsuccessful) were developed in OpenSim (v4.0) that incorporated subject specific tear characteristics, muscle peak isometric force, in-vivo kinematics and bony morphology. The models were driven with experimental kinematics and the magnitude and orientation of the net muscle force was determined during scapular plane abduction at pre- and post-exercise therapy timepoints. Subjects unsuccessfully treated had less inferiorly oriented net muscle forces pre- and post-exercise therapy compared to subjects successfully treated (p = 0.039 & 0.045, respectively). No differences were observed in the magnitude of the net muscle force (p > 0.05). The current study developed novel computational musculoskeletal models with subject specific inputs capable of distinguishing between subjects successfully and unsuccessfully treated with exercise therapy. A less inferiorly oriented net muscle force in subjects unsuccessfully treated may increase the risk of superior migration leading to impingement. Adjustments to exercise therapy programs may be warranted to avoid surgery in subjects at risk of unsuccessful treatment.

Rotator cuff isometric exercises in combination with scapular muscle strengthening and stretching in individuals with rotator cuff tendinopathy: A multiple-subject case report

BACKGROUND AND PURPOSE

To assess the effects of a rehabilitation protocol of rotator cuff (RC) isometrics coupled with traditional shoulder exercises on patient-rated outcomes, muscle strength, and electromyographic activity in individuals with RC tendinopathy.

METHODS

Eleven individuals (8 women and 3 men, 37.9 ± 5.6 years) with RC tendinopathy performed isometric RC exercises in combination with scapular muscle stretching and strengthening for 6 weeks. Treatment effects were assessed with patient-rated pain and shoulder function, isometric muscle strength, electromyographic activity during arm elevation and internal and external shoulder rotation, and pain during arm elevation before and at the end of the first session, and after 6 weeks of intervention.

RESULTS

There were improvements in pain and shoulder function, increased isometric muscle strength for arm elevation and internal rotation, increased muscle activity of the infraspinatus and serratus anterior, and reduced pain during arm elevation after 6 weeks of intervention.

DISCUSSION

This case report showed improvements on pain and function, increases on isometric strength of the shoulder and on electromyographic activity of the serratus anterior and infraspinatus muscles, as well as decreases on pain during arm elevation, after a 6-week intervention of RC isometric exercises associated with scapular muscle stretching and strengthening in patients with RC tendinopathy.

Scapular stabilization exercise training improves treatment effectiveness on shoulder pain, scapular dyskinesis, muscle strength, and function in patients with subacromial pain syndrome: A randomized controlled trial

INTRODUCTION

Subacromial pain syndrome (SPS) is a common cause of shoulder pain, and is associated with functional limitation, workdays lost, disability, and poor quality of life.

PURPOSE

Our purpose was to investigate the effects of scapular stabilization exercises in patients with SPS.

METHOD

Sixty-four patients with SPS who also exhibit observable scapular dyskinesis defined by the scapular dyskinesis test were recruited and randomized to scapular stabilization exercise training group or to control group. All participants received the same rehabilitation protocol including glenohumeral and scapular mobilization, pendulum exercises, shoulder stretching, range of motion exercises, strengthening, and proprioceptive exercises. Patients in the scapular stabilization exercise training group performed additional scapular stabilization exercises. The presence of scapular dyskinesis, shoulder pain severity, motion, muscle strength, scapular upward rotation, and shoulder disability were assessed before and after the four-week rehabilitation program.

RESULTS

The scapular stabilization exercise training group had better improvement in scapular dyskinesis, pain, muscle strength, and shoulder disability compared to the control group (p < 0.05). However, there was no statistically significant time-group interaction regarding shoulder motion and scapular upward rotation (p > 0.05).

CONCLUSIONS

Scapular stabilization exercises added to the shoulder mobilization, stretching, and strengthening are effective in improving scapular dyskinesis, reducing pain, increasing muscle strength and shoulder function in patients with SPS accompanied by scapular dyskinesis.

Normal values of scapular muscle activity ratio during arm elevation and the relationship to muscle strength and sex difference

BACKGROUND

The normal value of the scapular muscle activity ratio during arm elevation is not clear.

OBJECTIVE

To obtain normal values of the scapular muscle activity ratio during arm elevation in healthy individuals.

METHODS

This cross-sectional study enrolled 47 healthy people. The participants performed shoulder flexion and lowered task with 90-degree movements every 2 seconds. Muscle activities of scapular muscles were measured. For normalization, the maximum isometric contraction of the shoulder flexion was measured at 90∘ (reference contraction). The integrated electromyographic value (IEMG) obtained during the task was normalized by IEMG during the reference contraction and the relative IEMG value was calculated. Then, the scapular muscle activity ratio was computed. The relationship between muscle strength and other factors was also investigated.

RESULTS

The median values for upper trapezius/serratus anterior and upper trapezius/lower trapezius were often approximately 1, and that for upper trapezius/middle trapezius was often between 1 and 2. The shoulder flexion isometric strength and scapular muscle activity ratio showed significant negative correlations in multiple phases.

CONCLUSION

Normal values for upper trapezius/serratus anterior and upper trapezius/lower trapezius during arm elevation and lowering were generally 1. Low muscle strength may contribute to an abnormal scapular muscle activity balance.

Isometric versus isotonic exercise in individuals with rotator cuff tendinopathy-Effects on shoulder pain, functioning, muscle strength, and electromyographic activity: A protocol for randomized clinical trial

INTRODUCTION

Rotator cuff tendinopathy is a common shoulder disorder in which the primary treatment is resistance exercises. Isometric exercises are being studied for lower limb tendinopathies but not for rotator cuff tendinopathy. This protocol for a randomized clinical trial aims to compare the effects of two types of exercise (isometric and isotonic) on shoulder pain, functioning, muscle strength, and electromyographic activity in individuals with rotator cuff tendinopathy.

METHODS

Forty-six individuals (18 to 60 years old) with shoulder pain for more than three months and unilateral supraspinatus and/or infraspinatus tendinopathy will participate in this trial. Individuals will be randomized into two exercise groups: isometric or isotonic. The following outcomes will be evaluated before and after the first session and after six weeks of intervention: shoulder pain and functioning; isometric strength of shoulder elevation and lateral and medial rotation; and electromyographic activity of medial deltoid, infraspinatus, serratus anterior, and lower trapezius. Groups will perform stretching and strengthening of periscapular muscles. The isometric group will perform three sets of 32 s, at 70% of maximal isometric strength. The isotonic group will perform concentric and eccentric exercises (2 s for each phase) in three sets of eight repetitions at a load of eight repetition maximum. The total time under tension of 96 s will be equal for both groups, and load will be adjusted in weeks three and five of the protocol. Treatment effect between groups will be analyzed using linear mixed model.

TRIAL REGISTRATION

Trial registration number: Universal Trial Number (UTN) code U1111-1284-7528 and Brazilian Clinical Trials Registry platform-RBR-3pvdvfk.

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.

Clinical Diagnosis of Common Overlapping Shoulder and Cervical Spine Disorders: A Review of Current Evidence

» Pain in the shoulder is a common orthopaedic complaint that can be caused by shoulder or neck pathologies.» Shoulder and neck pathologies often coexist, among which one may be a predisposing factor for the other.» History, physical examination, and diagnostic injections can be used to discern the cause of shoulder pain and guide treatment.

The prevalence and risk factors for physical impairments in Chinese post-cancer treated breast cancer survivors: a 4 years' cross-sectional study at a single center

The incidence of breast cancer in China was 19.2% in 2018, with a five-year survival rate of up to 80%. The impairments that may result from breast cancer treatment, such as lymphedema, pain, and symptoms related to nerve damage, could have long-term side effects. Its prevalence and symptom profile have been commonly reported in various countries, but such data are rarely available for China. Physical function was assessed in 138 breast cancer survivors (BCSs) in the study. The prevalence of lymphedema (65.9%) was higher than that of pain (31.2%), shoulder range of motion (ROM) restriction (20.3%), grip strength restriction (GSR) (21.7%) and paresthesia (11.6%). These impairments mainly appeared within 28 months after breast cancer diagnosis, but could happen in 10 years. Carcinoma in situ and radiotherapy (RT) were related to the occurrence of lymphedema (respectively B = -1.8, p = 0.003; B = 1.3, p = 0.001). RT and delayed rehabilitation time (DRT) may increase the severity of lymphedema (respectively p = 0.003, p = 0.010). Breast conserving surgery (B = -2.1, p = 0.002) and the occurrence of AWS (B = 3.1, p = 0.006) were related to the occurrence of pain. The occurrence of brachial plexus injury (BPI) (B = 3.1, p < 0.001) and pain (B = 1.9, p = 0.002) improved the occurrence of shoulder ROM restriction. The occurrence of BPI (B = 3.6, p < 0.001) improved the occurrence of GSR. The occurrence of pain (B = 2.1, p = 0.001) improved the occurrence of paresthesia. These findings prompt us to further investigate the actual rehabilitation needs of survivors and the specific barriers to rehabilitation in the following research.

Inertial Sensors and Pressure Pain Threshold to Evaluate People with Primary Adhesive Capsulitis: Comparison with Healthy Controls and Effects of a Physiotherapy Protocol

Inertial sensors (IMUs) have been recently widely used in exercise and rehabilitation science as they can provide reliable quantitative measures of range of motion (RoM). Moreover, the pressure pain threshold (PPT) evaluation provides an objective measure of pain sensation in different body areas. The aim of this study was to evaluate the efficacy of physiotherapy treatment in people with adhesive capsulitis in terms of RoM and pain improvement measured by IMUs and the PPT. A combined prospective cohort/cross-sectional study was conducted. Nineteen individuals with adhesive capsulitis (10/19 females, 54 ± 8 years) and nineteen healthy controls (10/19 females, 51 ± 6 years) were evaluated for active glenohumeral joint RoM and PPT on shoulder body areas. Then, individuals with adhesive capsulitis were invited to 20 sessions of a physiotherapy protocol, and the assessments were repeated within 1 week from the last session. The range of motion in the flexion (p = 0.001) and abduction (p < 0.001) of the shoulder increased significantly after the physiotherapy protocol. Similarly, the PPT was found to increase significantly in all the assessed shoulder body areas, leading to no significant differences compared to the healthy controls. IMU and PPT assessments could be used to evaluate the efficacy of physical therapy in people with adhesive capsulitis.

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.

Upper-crossed syndrome and disability in shoulder adhesive capsulitis

STUDY DESIGN

Cross-sectional analytical study.

INTRODUCTION

Adhesive capsulitis (AC) is a long-standing condition with varying extents of disability seen among patients. The role of postural manifestations and contractile tissue involvement in this condition is poorly understood and yet to be explored.

PURPOSE

This study aimed to analyze if individuals with adhesive capsulitis demonstrated the characteristics of an upper crossed syndrome (UCS) postural manifestation and whether or not its presence affected the extent of disability experienced by this population.

METHODS

Sixty-five individuals with AC were assessed for the presence of UCS. Scapular muscle strength and length alterations, forward head posture (FHP), and disability were assessed and compared between those with and without UCS. Paired T test and an independent T test were utilized to compare means within and between these groups, respectively, while non-parametric measures were utilized for their skewed counterparts. Phi coefficient (φ) was used to determine the strength of association between the descriptive patient characteristics. The correlation between symptom duration and degree of postural involvement was analyzed using Pearson's correlation coefficient.

RESULTS

43.1% of the study population demonstrated UCS and 80% FHP with a significant negative correlation between Cranio Vertebral Angle and chronicity of AC (r = -0.27). Individuals with AC demonstrated significantly decreased scapular muscle strength (p = <.001) and pectoralis minor length on the affected side (p = .03). No differences were seen between groups with and without UCS. The mean SPADI scores between groups demonstrated a more significant level of perceived pain and disability in individuals with UCS (p = .049).

CONCLUSIONS

As seen in UCS, individuals with AC demonstrated alterations in movement patterns and posture. UCS was seen to contribute towards the existing disability in AC. This study suggests a careful evaluation and intervention based on these findings to document its effect on pain and dysfunction in AC.

Ischemic compression associated with joint mobilization does not promote additional clinical effects in individuals with rotator cuff related shoulder pain: A randomized clinical trial

OBJECTIVE

The objective of this study was to verify which are the additional effects of the ischemic compression (IC) technique associated with joint mobilization techniques on pain, morphological aspects of myofascial trigger points (MTrPs), function, and psychological aspects in individuals with rotator cuff-related shoulder pain (RCRSP).

METHODS

Sixty individuals with RCRSP were randomly allocated intervention sessions the Mobilization Group (MG, n = 20), only joint mobilizations of the shoulder complex; intervention sessions Compression Group (CG, n = 20), with the same mobilizations associated with the IC over MTrPs; and Placebo Group (PG, n = 20), with the same mobilizations associated with placebo of IC. All interventions performed 2 per week, for 6-weeks. Pain was assessed by Visual Analogue Scale and function by the Disabilities of the Arm, Shoulder and Hand questionnaire. The kinesiophobia, pain catastrophizing, perception of improvement, mobility, pain threshold and area the MTrPs were also evaluated at baseline (week-0), after 6-weeks and after 10-weeks.

RESULTS

There were no between-group difference in pain: CG-MG 0.8 (95% CI 0.4 to 1.2), CG-PG 0.5 (95% CI 0.0 to 0.9), MG-PG -0.3 (95% CI -0.8 to 0.1) after 6-weeks and CG-MG 0.1 (95% CI -0.2 to 0.5), CG-PG -0.7 (95% CI -0.9 to -0,4), MG-PG -0,8 (95% CI -1.07 to 0.5) at 10-weeks. Similar effects were observed on function, characteristics of MTrPs and psychological aspects.

CONCLUSION

The IC technique on the MTrPs of the upper trapezius muscle associated with joint mobilization techniques has no additional effect on pain in individuals with RCRSP.

TRIAL REGISTRATION

RBR-44v8y7.

Short-term outcomes after primary reverse total shoulder arthroplasty in patients with cervical spine pathology or previous cervical spine surgery compared to those without

BACKGROUND

Cervical spine (c-spine) and shoulder pathology have been known to cause similar symptoms and often co-exist, making an accurate diagnosis difficult, especially in an elderly population. Reverse total shoulder arthroplasty (rTSA) has been shown to decrease pain and improve quality of life when shoulder pathology is the source of pain and disability. The purpose of this study was to identify the prevalence of c-spine pathology in a cohort of patients who underwent rTSA and to compare postoperative outcome scores to a cohort without c-spine pathology.

METHODS

A retrospective review was performed utilizing a single institution's operative records of primary rTSAs. Radiology reports, imaging, and operative reports were reviewed, and presence of any c-spine pathology or previous surgery were recorded. Additionally, postoperative outcome scores (American Shoulder and Elbow Surgeons [ASES], Constant Score, University of California, Los Angeles [UCLA], and Simple Shoulder Test [SST]) were evaluated at >2 years post-rTSA.

RESULTS

A total of 438 primary rTSA cases were evaluated. Of these, 143 (32.6%) had documentation of prior c-spine pathology and/or history of previous c-spine surgery. After applying further exclusion criteria, a total of 50 patients with c-spine pathology and 108 patients without c-spine pathology were found to have complete medical records and postoperative outcome scores to allow comparison between groups. Patients without c-spine pathology were found to have statistically higher postoperative UCLA, ASES, and SST scores when compared to patients with c-spine pathology. Patients without c-spine pathology also demonstrated a significant improvement in the difference between their postoperative and preoperative UCLA and ASES scores.

CONCLUSION

This study demonstrated a high prevalence of c-spine pathology (32.6%) in a cohort of patients who underwent primary rTSA. Additionally, short-term outcome scores of patients undergoing rTSA with concomitant c-spine pathology are significantly lower than those of patients without a history of c-spine pathology.

Prompt Impact of Muscle Energy Technique on Pectoralis Muscle Tightness in Computer Users: A Quasi-Experimental Study

Tightness of the pectoralis minor muscle has been a common characteristic of abnormal posture. Prolonged inappropriate posture while using computers/laptops results in musculoskeletal problems, mainly in the upper limb. This study aims to see how the muscular energy technique affected pectoralis minor tightness in computer users right away. This study included 65 individuals aged 20-40 years following the inclusion/exclusion criteria. Participants received muscle energy technique for the pectoralis minor muscle. Pre- and post-assessment included the evaluation of pectoralis minor length, round shoulder posture (RSP), and forward head posture (FHP). We used the Kolmogorov-Smirnov test to assess the normality of data, as this study included > 50 participants. Data analysis was conducted using a paired t-test for within-group analysis. The outcome measures demonstrated significant improvement (p < 0.001). In conclusion, the muscle energy technique is effective in reducing muscle tightness, improving RSP and reducing FHP.

Monitoring Scapular Kinematics through Wearable Magneto-Inertial Measurement Units: State of the Art and New Frontiers

Monitoring shoulder kinematics, including the scapular segment, is of great relevance in the orthopaedic field. Among wearable systems, magneto-inertial measurement units (M-IMUs) represent a valid alternative for applications in unstructured environments. The aim of this systematic literature review is to report and describe the existing methods to estimate 3D scapular movements through wearable systems integrating M-IMUs. A comprehensive search of PubMed, IEEE Xplore, and Web of Science was performed, and results were included up to May 2023. A total of 14 articles was included. The results showed high heterogeneity among studies regarding calibration procedures, tasks executed, and the population. Two different techniques were described, i.e., with the x-axis aligned with the cranial edge of the scapular spine or positioned on the flat surface of the acromion with the x-axis perpendicular to the scapular spine. Sensor placement affected the scapular motion and, also, the kinematic output. Further studies should be conducted to establish a universal protocol that reduces the variability among studies. Establishing a protocol that can be carried out without difficulty or pain by patients with shoulder musculoskeletal disorders could be of great clinical relevance for patients and clinicians to monitor 3D scapular kinematics in unstructured settings or during common clinical practice.

The Effects of Body Positions and Abduction Angles on Shoulder Muscle Activity Patterns during External Rotation Exercises

BACKGROUND

Excess and repetitive glenohumeral external rotation (ER) is at a higher risk for shoulder injuries, which occurs frequently in professional sports and specific occupations. Current rehabilitation programs emphasize selective targeting of muscle activity, which can help restore dysfunctional muscle imbalances or prevent injuries. However, the impact of different body postures on GH muscle activity during ER exercises has not been fully understood. Therefore, the purpose of this study was to investigate shoulder EMG activity for different body positions and humeral abduction angles during ER exercises.

METHOD

Twenty-three healthy young men (age: 22.3 ± 2.3, height: 175.75 ± 4.02, mass: 75.37 ± 9.14) participated in this study. Surface Electromyography was recorded from seven shoulder muscles: upper trapezius, lower trapezius, serratus anterior, infraspinatus, and deltoid. Six ER exercises: three postures (sitting, supine lying, and prone lying) and two abduction angles (ABD; 45° and 90°) were tested using an isokinetic dynamometer.

RESULTS

During a sitting position, the lower trapezius/upper trapezius muscle activity ratios were significantly increased for sitting compared to supine lying and prone lying (p < 0.001, p = 0.004). Serratus anterior/upper trapezius co-contraction indices were significantly increased for 90° than 45° ABD (p < 0.001).

CONCLUSION

These findings can provide insight into new training programs aimed at restoring GH muscle imbalances.

De Quervain Tenosynovitis as a Risk Factor of New-Onset Adhesive Capsulitis: A Nationwide Cohort Study

This study investigated the association of de Quervain tenosynovitis (DQT) with subsequent adhesive capsulitis (AC) development. Patients with DQT between 2001 and 2017 from the Taiwan National Health Insurance Research Database were the DQT cohort. The 1:1 propensity score matching method was applied for creating control cohort. The primary outcome was defined as new-onset of AC at least 1 year after the date of confirmed diagnosis of DQT. In total, 32,048 patients with mean age 45.3 years were included. DQT was significantly positively associated with risk of new-onset AC after adjustment for baseline characteristics. Furthermore, severe DQT requiring rehabilitation was positively associated with risk of new-onset AC. In addition, male gender and age under 40 may be additional risk factors for new-onset AC, compared to female gender and age over 40. Cumulative incidence of AC after 17 years was 24.1% among patients with severe DQT requiring rehabilitation and was 20.8% among patients with DQT without rehabilitation. This is the first population-based study to demonstrate an association between DQT and new-onset AC. The findings recommend that preventive occupational therapy, including active modification for the shoulder joint and adjustments to daily activities, may be necessary for patients with DQT to reduce their risk of developing AC.

Scapular Resting Posture and Scapulohumeral Rhythm Adaptations in Volleyball Players: Implications for Clinical Shoulder Assessment in Athletes

Volleyball players develop shoulder sports-related adaptations due to repetitive overhead motions. It is essential to differentiate between these sports-related adaptations and pathological patterns in clinical assessments, particularly on scapular resting posture and scapulohumeral rhythm. Using an electromagnetic tracking system, the 3D shoulder kinematics of 30 male elite asymptomatic volleyball players and a matching control group were recorded at rest and in eight humeral elevation positions, in 15-degree increments from 15 to 120 degrees. The results indicated that the dominant scapular resting posture of the volleyball group was more anteriorly tilted than the control group (Volleyball: mean = -12.02°, STD = 4.16°; Control: mean = -7.45°, STD = 5.42°; Mean difference = 4.57°; STD = 6.85°; CI95% = 2.1° to 7.1°). The scapulohumeral rhythm in the volleyball group showed greater scapular internal rotation (Volleyball: mean = 41.60°, STD = 9.14°; Control: mean = 35.60°, STD = 6.03°; mean difference = 6.02°, STD = 1.47°; CI95% = 4.80° to 7.25°) and anterior tilt (Volleyball: mean = -9.10°, STD = 5.87°; mean = -2.3°, STD = 9.18°; mean difference = 6.88°, STD = 0.66°; CI95% = 6.34° to 7.43°). These findings suggest that volleyball players have developed a sports-related scapular adaptive pattern. This information may be valuable for clinical assessment and rehabilitation planning in injured volleyball players and may aid in the decision-making process for determining a safe return-to-play after a shoulder injury.

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.

Effectiveness of scapular mobilization in people with subacromial impingement syndrome: A randomized controlled trial

BACKGROUND

Scapular mobilization is a manual therapy technique widely used in the management of musculoskeletal disorders of the shoulder.

OBJECTIVE

To determine the effects of scapular mobilization in addition to an exercise program in people with subacromial impingement syndrome (SIS).

METHODS

Seventy-two adults with SIS were randomly allocated to 1 of 2 groups. The control group (n=36) participated in a 6-week exercise program, and the intervention group (n = 36) participated in the same exercise program plus passive manual scapular mobilization. Both groups were assessed at baseline and 6 weeks (end of treatment). The primary outcome measure was upper limb function assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Secondary outcome measures were the Constant-Murley questionnaire, pain (visual analog scale [VAS]), and scapular upward rotation.

RESULTS

All participants completed the trial. The between-group difference in DASH was -1.1 points (Cohen d = 0.05; p = 0.911), Constant-Murley 2.1 points (Cohen d = 0.08; p = 0.841), VAS rating of pain at rest -0.1 cm (Cohen d = 0.05; p = 0.684), and VAS rating of pain during movement -0.2 cm (Cohen d = 0.09; p = 0.764); scapular upward rotation at rest (arm by the side) was 0.6° (Cohen d = 0.09; p = 0.237), at 45° shoulder abduction was 0.8° (Cohen d = 0.13; p = 0.096), at 90° was 0.1° (Cohen d = 0.04; p = 0.783), and at 135° was 0.1° (Cohen d = 0.07; p = 0.886). Most differences were in favor of the intervention group; however, the effect sizes were weak and not statistically significant.

CONCLUSIONS

In the short-term, the addition of scapular mobilization did not provide significant clinical benefits in terms of function, pain or scapular motion in participants with SIS.

TRIAL REGISTRATION

Brazilian registry of clinical trials UTN number U1111-1226-2081. Registered February 25, 2019.

Nonoperative Treatment of Rotator Cuff Tears

Rotator cuff tears are common with prevalence increasing with age. Diagnosis by physical examination may require a cluster of tests. Although radiographs can be helpful, MRI, MRI arthrography, and ultrasound represent the most used imaging technique to identify rotator cuff tears. Although surgery is sometimes necessary, a large portion of patients may respond to conservative treatment including physical therapy and injections. Physical therapy should include restoring the range of motion, addressing any pectoralis minor or posterior capsule stiffness, and restoring motor control/strength to the scapula and rotator cuff. Other conservative treatments may include nonsteroidal anti-inflammatory drugs, corticosteroid injects, and platelet-rich plasma.

The effect of EMG biofeedback training on muscle activation in an impingement population

Subacromial impingement syndrome (SAIS) is one of the most diagnosed causes of pain in the upper extremity. The purpose of this study was to investigate muscle activity between asymptomatic and SAIS shoulders on the same subject while understanding the effectiveness of EMG biofeedback training (EBFB) on bilateral overhead movements. Ten participants (7 male), that tested positive for 2/3 SAIS clinical tests, volunteered for the study. Bilateral muscle activity was measured via electrodes on the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and lumbar paraspinals (LP). Participants performed bilateral scapular plane overhead movements before and after EBFB. EBFB consisted of 10 bilateral repetitions of I, W, T, and Y exercises focused on reducing UT and increasing LT and SA activity. Prior to EBFB, no significant difference in muscle activity was present between sides. A significant main effect of time indicated that after EBFB both sides exhibited reduced UT activity at 60° (p = 0.003) and 90° (p = 0.036), LT activity was increased at all measured humeral angles (p < 0.0005), and SA muscle activity was increased at 110° (p = 0.001). EBFB in conjunction with scapular based exercise effectively alters muscle activity of asymptomatic and symptomatic scapular musculature.

Biomechanical analysis of plating techniques for unstable lateral clavicle fractures with coracoclavicular ligament disruption (Neer type IIB)

BACKGROUND

Neer type IIB lateral clavicle fractures are inherently unstable fractures with associated disruption of the coracoclavicular (CC) ligaments. Because of the high rate of nonunion and malunion, surgical fixation is recommended; however, no consensus has been reached regarding the optimal fixation method. A new plating technique using a superior lateral locking plate with anteroposterior (AP) locking screws, resulting in orthogonal fixation in the lateral fragment, has been designed to enhance stability and reduce implant failure. The purpose of this study was to biomechanically compare 3 different clavicle plating constructs within a fresh frozen human cadaveric shoulder model.

METHODS

Twenty-four fresh frozen cadaveric shoulders were randomized into 3 groups (n = 8 specimens): group 1, lateral locking plate only (Medartis Aptus Superior Lateral Plate); group 2, lateral locking plate with CC stabilization (No. 2 FiberWire); and group 3, lateral locking plate with 2 AP locking screws stabilizing the lateral fragment. All specimens were subject to cyclic loading of 70 N for 500 cycles. Data were analyzed for gap formation after cyclic loading, construct stiffness, and ultimate load to failure, defined by a marked decrease in the load displacement curve.

RESULTS

After 500 cycles, there was no statistically significant difference between the 3 groups in gap formation (P = .179). No specimen (0/24) failed during cyclic loading. Ultimate load to failure was significantly higher in group 3 compared to group 1 (286 N vs. 167 N; P = .022), but not to group 2 (286 N vs. 246 N; P = .604). There were no statistically significant differences in stiffness (group 1: 504 N/mm; group 2: 564 N/mm; group 3: 512 N/mm; P = .712). Peri-implant fracture was the primary mode of failure for all 3 groups, with group 3 demonstrating the lowest rate of peri-implant fractures (group 1: 6/8; group 2: 7/8; group 3: 4/8; P = .243).

CONCLUSION

Biomechanical evaluation of the clavicle plating techniques showed effective fixation across all specimens at 500 cycles. The lateral locking plate with orthogonal AP locking screw fixation in the lateral fragment demonstrated the greatest ultimate failure load, followed by the lateral locking plate with CC stabilization. This new plating technique showed compatible stiffness and gap formation when compared to conventional lateral locking plates as well as plates with CC fixation. The use of orthogonal screw fixation in the distal fragment may negate against the need for CC stabilization in these types of fractures, thus minimizing surgical dissection around the coracoid and potential complications.

Effectiveness of Therapeutical Interventions on the Scapulothoracic Complex in the Management of Patients with Subacromial Impingement and Frozen Shoulder: A Systematic Review

Shoulder pain is one the most common musculoskeletal complaints. The most common pathological causes of shoulder pain in the general population are subacromial impingement syndrome and adhesive capsulitis, commonly referred to as "frozen shoulder". The purpose of this study was to evaluate the role of the scapulo-thoracic complex, particularly in scapular kinematic functions, in rehabilitative interventions for shoulder pain in patients suffering from these two common conditions. This systematic review was performed using the scientific search engines PubMed, PEDro and Cochrane Library, considering only randomized controlled clinical trials. Selected articles were evaluated according to the level of evidence and methodological quality. Thirteen randomized clinical trials were selected. Interventions have been divided into three macro-categories: (1) manual therapy in patients with subacromial impingement, (2) therapeutic exercise programs including interventions on the scapulothoracic complex in patients with subacromial impingement syndrome, and (3) therapeutic exercise programs including interventions on the scapulothoracic complex in patients with frozen shoulder. Following this, a qualitative analysis was performed according to outcomes such as pain, shoulder function, and scapular kinematics. Physiotherapy exercise programs that included scapular motor control training and scapular mobilizations, in particular, those of the scapulo-thoracic complex in scapular kinematic function, represent valid alternatives in the management of patients with subacromial impingement syndrome.

Impact of cervical spine pathology on outcomes after total shoulder arthroplasty

BACKGROUND

Cervical spine pathology can affect the supporting muscles and function of the shoulder and contribute to shoulder and arm pain and hence may impact postoperative outcomes following shoulder arthroplasty. The purpose of this study was to evaluate the impact of a history of cervical spine arthrodesis and its timing, before or after total shoulder arthroplasty (TSA), on the outcomes of TSA. Our hypothesis is that a history of cervical arthrodesis (CA) will negatively impact patient outcomes after shoulder arthroplasty.

METHODS

A retrospective analysis was performed on a prospectively collected cohort at a single institution. Anatomic (aTSA) and reverse TSA (rTSA) patients with CA were identified and compared to a cohort of patients without CA (NCA) enrolled in an institutional registry from 2011 to 2020. Demographic characteristics, diagnoses, implant type, range of motion, adverse events, and clinical outcome metric scores (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], Constant, Shoulder Function score, patient satisfaction) were recorded. Outcomes between cohorts were analyzed using conventional statistics as well as stratification by minimal clinically important difference and substantial clinical benefit (SCB) thresholds where applicable.

RESULTS

Of the 573 TSAs evaluated, 48 (20a CA-aTSA and 28 CA-rTSA) had a history of CA and 525 (280 NCA-aTSA and 245 NCA-rTSA) had no history of CA. The CA-TSA (aTSA and rTSA) had lower Constant, ASES, and Shoulder Function scores postoperatively as well as less improvement in active external rotation and an overall lower satisfaction rating (P < .05 for all) compared with NCA-TSA. The adverse event rate in the CA-TSA cohort was higher compared with the NCA-TSA cohort (25% vs. 6.5% [rTSA; P = .004] and 24.5% vs. 11% [aTSA; P = .068]). Optimal cutoff analysis showed that a time from CA to TSA of greater than 1.33 years had a sensitivity of 75.0% and specificity of 75.0% in predicting achievement of SCB for ASES score.

CONCLUSION

The current study demonstrates that patients with a history of CA undergoing shoulder arthroplasty results in lower postoperative functional outcomes, lower satisfaction, and higher rates of postoperative adverse events requiring surgical revision when compared to a cohort without a history of CA. Additionally, the current study demonstrates that a time interval of at least 16 months between CA and shoulder arthroplasty optimizes the chances of achieving SCB for ASES score.

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.

Prevalence of scapular dyskinesis in office workers with neck and scapular pain

Objectives. This study aimed to investigate the presence of scapular dyskinesis (SD) in office workers with neck and scapular complaints. The postural malalignment and related muscle adaptations were also explored. Methods. SD and its subtypes were determined. Postural deviations and the length of commonly reported muscle tightness were evaluated. Results. Among 99 participants, 90% of them had SD. Considering both sides or 198 scapula, 90.4% were identified as having painful scapula and 19% as having painless scapula. There was a difference in the proportion of SD on painful (93%) and painless (69%) sides. Postural deviations including rounded shoulder (100%), forward head (43.3%) and thoracic hyperkyphosis (54.5%) were prevalent. Persons with type III SD had a higher percentage of forward head than other types. There was also tightness of the pectoralis minor (100%), levator scapulae (93.0%) and upper trapezius (98.3%) muscles without different proportions among types of SD. The greatest proportion of persons with SD had tightness of the levator scapulae. Conclusions. There was a high prevalence of SD among office workers with neck and scapular complaints. SD was also associated with abnormal posture and muscle tightness. The proper management of SD and working posture is warranted.

Challenges for Optimization of Reverse Shoulder Arthroplasty Part II: Subacromial Space, Scapular Posture, Moment Arms and Muscle Tensioning

In part II of this comprehensive review on the optimization of reverse shoulder arthroplasty (RSA), we focus on three other challenges: 1. "Conservation of sufficient subacromial and coracohumeral space"; 2. "Scapular posture"; and 3. "Moment arms and muscle tensioning". This paper follows a detailed review of the basic science and clinical literature of the challenges in part I: 1. "External rotation and extension" and 2. "Internal rotation". "Conservation of sufficient subacromial and coracohumeral space" and "Scapular posture" may have a significant impact on the passive and active function of RSA. Understanding the implications of "Moment arms and muscle tensioning" is essential to optimize active force generation and RSA performance. An awareness and understanding of the challenges of the optimization of RSA help surgeons prevent complications and improve RSA function and raise further research questions for ongoing study.

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.

Comparison of the Effects of Isometric Horizontal Abduction on Shoulder Muscle Activity During Wall Push-Up Plus and Wall Slide in Individuals With Scapular Winging

CONTEXT

Wall push-up plus (WPP) and wall slide (WS) are commonly prescribed in early rehabilitation to increase serratus anterior (SA) muscle activity. For individuals with scapular winging (SW), synergistic muscles such as upper trapezius (UT) and pectoralis major (PM) may compensate for weak SA during scapular movement. However, no studies have applied isometric horizontal abduction (IHA) during WS in individuals with SW nor have compared it with WPP with IHA.

OBJECTIVES

This study compared the effects of IHA on shoulder muscle activity during WPP and WS exercises in individuals with SW.

DESIGN

Cross-sectional study; 2-way repeated-measures analysis of variance was used to assess the statistical significance of observed differences in SA, UT, PM, lower trapezius (LT), and infraspinatus (IS) muscle activities.

SETTING

Research laboratory.

PATIENTS

We recruited 30 individuals with SW comprising 20 men and 10 women.

INTERVENTIONS

The individuals performed WPP and WS exercises with and without IHA using Thera-Band.

MAIN OUTCOME MEASURES

Surface electromyography was used to measure muscle activity of the SA, UT, PM, LT, and IS during the isometric phase of WPP and WS. Maximal voluntary isometric contractions were recorded to normalize electromyographic data.

RESULTS

There was no significant interaction between IHA application and exercise type for any of the shoulder muscles. IHA application increased SA (P = .008), UT (P = .001), LT (P = .009), and IS (P = .000) activities and decreased PM (P = .001) activity compared with those without IHA. WS exercises elicited higher PM (P = .017) and LT (P = .011) activities than WPP.

CONCLUSION

WPP and WS with IHA may be effective in increasing the muscle activities of shoulder stabilizers and preventing overactivation of PM activity. WPP may be recommended for individuals with overactivated PM, whereas WS may be used to increase LT activity.

Effects of an exercise program plus manual therapy in a patient with failed neck surgery syndrome: A case report

BACKGROUND

Patients who have undergone cervical surgery may present pain and dysfunction in the upper limb, which is often referred to as failed neck surgery syndrome. Little is known about the effects of an exercise program plus manual therapy in the treatment of prolonged neuropathic pain of the upper quadrant in a patient with failed neck surgery.

CASE DESCRIPTION

A 66-year-old woman consulted for neuropathic pain and dysfunction during grasping activities, as a result of failed neck surgery after 12 months. Clinical, functional, and electromyographic measurements were recorded at baseline and after treatment. The patient underwent a treatment for six weeks based on manual therapy for the upper limb and cervical spine and an exercise program for the scapular muscles, rotator cuff and wrist extensor muscles.

OUTCOMES

Positive clinically significant changes were observed in the Neuropathic Pain Questionnaire (DN4) (baseline = 7 points; post-treatment = 4 points), Neck Disability Index (NDI) (baseline = 36; post-treatment = 18 points), QuickDASH (baseline = 78; post- treatment = 32 points), Upper Limb Neurodynamic Test 1 (ULNT-1) (baseline = 75°; post- treatment = 42°) and grip strength (GS) (baseline = 23 kgf; post-treatment = to 32 kgf). Improvements in the surface electromyographic (sEMG) activity of the upper trapezius (UT), infraspinatus (IS) and radial wrist extensors (RWE) muscles also seemed to occur after treatment.

CONCLUSION

Treatment helped relieve neuropathic pain, decrease neck disability, and improve general upper limb function.

Comparison of scapular position in elite tennis players with and without shoulder impingement: A case-control study

BACKGROUND

To maximize the ball velocity in the tennis sever, the shoulder plays a key role in the kinetic chain. But shoulder inefficiency leads to shoulder injuries such as shoulder impingement syndrome (SIS). Thus, to verify the scapular movements during the tennis serve could help prevent shoulder injury in tennis players.

OBJECTIVE

This case-control study aimed to verify the scapular movements during flat first serve for elite tennis players with shoulder impingement syndrome compared to those without it.

METHODS

Eight elite tennis players (4 males and 4 females) with SIS and 8 elite healthy players (4 males and 4 females) performed flat first serves, and the three-dimensional scapular kinematic data was recorded using the Qualisys motion capture system through spherical reflective markers including the acromion marker cluster.

RESULTS

The scapula was more internally rotated (median difference: 10.40∘) in the male players with SIS than in those without it at the maximally externally rotated humerothoracic joint during flat first serve, and female players with SIS (median difference: 7.16∘ and 11.28∘, respectively) had more internally rotated scapula at the maximally externally rotated humerothoracic joint and ball impact.

CONCLUSION

Increased scapular internal rotation may be something that affects shoulder injuries in the overhead sports, and it may help to prevent and rehabilitate overhead injuries including SIS.