Scapular dyskinesis: practical applications

The latissimus dorsi creates a dynamic track for the inferior angle of the scapula during arm abduction in humans

BACKGROUND

The importance of several scapulothoracic muscles, including trapezius and serratus anterior, in maintaining physiological scapula kinematics has been highlighted in the past. However, the relationship between the scapula and the latissimus dorsi muscle remains unclear. Our clinical surgical observation is that the latissimus dorsi does not directly attach but rather runs superficial to the inferior angle of the scapula. Based on this observation, we hypothesise that the latissimus dorsi creates a dynamic track on which the scapula glides under the muscle belly during elevation of the arm, creating the latissimus-scapula overlap (LSO).

METHODS

All consecutive patients who had a whole-body computed tomography scan (CT) in case of polytrauma evaluation between 2018 and 2021, with complete depiction of the scapula and latissimus dorsi muscle, were analysed. 150 shoulders in 90 patients with arms up were matched according to their age (within five years), gender, and affected side with 150 shoulders in 88 patients with arms down. Patients with pathologies of the upper extremities or thorax that potentially could alter LSO measurements were excluded. LSO was calculated as a ratio of the measured area of the latissimus dorsi projection on the scapula and the total scapula area.

RESULTS

The mean age of the 178 patients (48 females; 13 males) was 60 years. The arms-up group showed a significantly higher LSO than the arms-down group (19.9 ± 6.3% vs. 2.7 ± 2.2%; p < 0.0001). In the arms-up group, approximately one fifth of the scapula was overlapped inferiorly by the muscle belly of the latissimus dorsi, contrary to the almost non-existing LSO in the arms-down group.

CONCLUSION

With arms up, humans show a significantly higher LSO in comparison to arms down indicating that the latissimus dorsi indeed creates a dynamic track on which the scapula is forced to travel during abduction of the arm. This finding of increased LSO during the elevation of the arm warrants further consideration of the role of the latissimus dorsi in scapula kinematics and potentially scapular dyskinesis.

LEVEL OF EVIDENCE

Level two diagnostic study.

Association of Scapular Dyskinesis with Neck and Shoulder Function and Training Period in Brazilian Ju-Jitsu Athletes

Background and Objectives: Neck and shoulder injuries are common in Brazilian ju-jitsu (BJJ) athletes, and scapular dyskinesis (SD) is associated with these injuries. This study aimed to investigate the prevalence of SD in BJJ athletes, their neck and shoulder function and strength, and the BJJ training period. Materials and Methods: Forty-eight BJJ athletes participated in the study. Years of experience with BJJ, belt, shoulder internal and external rotation strength, neck strength, neck disability index (NDI), and SD were measured. Results: Approximately 31 BJJ athletes (64.6%) showed SD, and the nondominant arm showed a more obvious SD (n = 22, 45.8%) than the dominant arm (n = 18, 37.5%). Those with over five years of BJJ training experience showed a significantly higher rate of SD (p = 0.006) than those with less than five years of experience. Shoulder isometric internal rotation strength was significantly weaker in the obvious SD group than in the normal SD group (p = 0.014). Neck isometric strength and NDI did not differ significantly between individuals with or without SD. Conclusions: SD was common among BJJ athletes, and more experienced BJJ athletes exhibited higher rates of SD. Shoulder rotational strength was weaker with SD. Further studies are necessary on the neck and shoulders of BJJ athletes with SD.

Comparison of Shoulder Kinematics and Muscle Activation of Female Elite Handball Players With and Without Pain—An Explorative Cross-Sectional Study

Non-traumatic shoulder injuries are common in team handball. However, many athletes continue to throw, despite pain in the shoulder. This study investigated upper body kinematics and muscle activation while throwing in female elite handball players with and without shoulder pain. Thirty female elite team handball players, 15 with pain (age 22.2 ± 2.9 yrs.) and 15 without pain (age 20.4 ± 2.6 yrs.) performed five standing throws in which joint kinematics and muscle activity were measured in the following muscles: pectoralis major, infraspinatus, serratus anterior, latissimus dorsi, and upper-, middle-, and lower trapezius. The main findings revealed that peak joint angles and angular velocities were not different between groups; however, group differences were observed in earlier timing of position and longer time spent in maximal shoulder extension and external shoulder rotation in the pain group compared with the no pain group. The pain group also revealed a significant lower muscle peak activity in the serratus anterior during the cocking phase compared to the no pain group. After the cocking phase and at ball release, the groups had similar activation. In conclusion, the present study showed group differences in appearance and time spent in maximal humerus extension and external rotation and a different serratus anterior muscle peak activity between elite handball players playing with and without shoulder pain, which are identified as possible mechanisms of adaptation to avoid pain.

EVALUATION OF SCAPULAR DYSKINESIA IN PATIENTS THAT UNDERWENT A LATARJET PROCEDURE

Objective

To quantitatively assess the scapular movement of patients who underwent Latarjet surgery and to identify if they present scapular dyskinesia (SD), as well as correlate with the clinic state and the elevation degree of the shoulder.

Methods

A cross-sectional study was carried out at the Movement Analysis Laboratory (LAM), at the Institute of Physical Activity and Sport Sciences, that quantitatively evaluated, using spherical retroreflective markers, the scapular movements of the control group (10 volunteers) and 22 patients (23 operated shoulders) that had been submitted to Latarjet surgery, between 2011 and 2016, with at least one year postoperative. The results of the control group were used as a parameter of normality and compared to those of the operated group. Posterior inclination, superior rotation, and medial rotation of the scapula were evaluated at angles of 60°, 90°, and 120° of elevation, both in ascending and descending phases. The statistical analysis used was the multivariate variance (MANOVA), comparing the right and left sides of the control group and, subsequently, the control group with the postoperative group (p = 0.05 in all tests).

Results

When comparing the mean of the results of the quantitative evaluation of the control group with the operated group, no statistically significant differences were found between the two groups and between the dominant and non-dominant sides of the control group.

Conclusion

Latarjet surgery does not cause SD, although there are alterations in some plane of the scapular movements in the ascending and/or descending phase. Level of Evidence III, Retrospective Comparative Study.

The adjunctive benefits of mirror cross education on kinetic chain exercise approach in volleyball athletes with scapular dyskinesis

BACKGROUND

Volleyball players as overhead athletes have the highest risk of developing Scapular Dyskinesis. The kinetic chain exercise-approach has gained a lot of attention because of its claims to provide an improved motor control and scapular kinematics. A form of cross exercise, known as mirror therapy, may enhance the effects of a Kinetic-Chain-Approach on scapular posture, upper and lower limb performance. The aim of this study was to investigate the adjunctive benefits of Mirror-Cross-Education in a Kinetic-Chain-Approach, in volleyball athletes with SD.

METHODS

39 professional volleyball athletes were randomly assigned to three groups of 13 each, two experimental, the Mirror-Cross-Education and Kinetic-Chain-Approach, and one control. Both experimental groups performed a Kinetic-Chain-Approach programme, however, the Mirror-Cross-Education group performed the exercise programme with the addition of two mirrors that allowed athletes to observe their opposite non-dyskinetic scapula. Scapular posture asymmetries in cm, the Y-Balance and the Upper-Quarter YBalance after normalizing by limb length the reach distance in each direction, were assessed before and after performing each intervention for 6 weeks.

RESULTS

3x2 two-way Mixed ANOVAs detected significant interactions on scapular posture (p=0.001) on both experimental groups when compared with the control. The Y-Balance and the Upper Quarter Y-Balance scores at both Mirror-Cross-Education and Kinetic-Chain-Approach groups showed significant differences when compared with the control (p<0.05). Overall, variables showed significant superiority of the Mirror-Cross-Education group.

CONCLUSIONS

The Mirror-Cross-Education demonstrated significant effects in scapular posture and in the functional balance tests of volleyball athletes with Scapular Dyskinesis.

Scapular movement impairments in individuals with subacromial pain syndrome based on scapular assistance test and scapula reposition test outcomes

BACKGROUND

Individuals with subacromial pain present with a variety of contributing impairments related to the movement problem. The scapular assistance test (SAT) and scapula reposition test (SRT) are proposed to identify shoulder pain related to abnormal scapular movement or position. It remains unknown if scapular movement related impairments are present in those with positive tests.

OBJECTIVES

To determine if scapular motion related impairments differ based on the result of the SAT or SRT in individuals with subacromial pain syndrome.

DESIGN

Cross-sectional METHOD: Sixty individuals with subacromial pain syndrome were included. Prior to obtaining results of the SAT and SRT, a single examiner measured scapular upward rotation and posterior tilt active and passive motion, pectoralis minor length, and strength of the middle trapezius, lower trapezius, and serratus anterior. Dynamic scapular motion was qualitatively assessed with the Scapular Dyskinesis Test. The Mann-Whitney U test assessed for differences based on the outcome of the SAT and SRT.

RESULTS

There was a significant difference (P = .023) in pectoralis minor length for the SAT. Participants with a positive SAT had decreased muscle length compared to those who tested negative. There were no significant differences in scapular motion or strength based on the result of either the SAT or SRT.

CONCLUSIONS

A positive SAT was associated with greater pectoralis minor length impairment, but not muscle strength or mobility. The SRT did not identify greater impairments in any of the scapular movement related impairments assessed. Individuals may vary in contributing impairments related to SAT or SRT results.

Exercise therapy may affect scapular position and motion in individuals with scapular dyskinesis: a systematic review of clinical trials

BACKGROUND

Therapeutic exercise for scapular muscles is suggested to be effective in reducing shoulder pain in patients with rotator cuff disorders, whereas its effectiveness on scapular position and motion has remained unclear. Therefore, the aim of this systematic review was to investigate whether exercise therapy improves scapular position and motion in individuals with scapular dyskinesis.

METHODS

This study is a wide systematic review including any type of clinical trial in which the effect of any type of therapeutic exercise, including scapular muscle strengthening, stretching, and scapular stabilization exercise, is investigated in adult participants.

RESULTS

Twenty studies were included in this systematic review. Studies were categorized on the basis of the techniques they used to measure scapular position and motion and the included participants. Methodologic quality of the studies was assessed by the Cochrane tool of assessing the risk of bias. Eight studies used 3-dimensional techniques for measuring scapular motions. Among them, 5 studies showed significant effects of exercise on scapular motion, of which 3 studies investigated individuals with subacromial impingement syndrome (SIS). The other 12 studies used 2-dimensional measurement techniques, of which 8 studies reported significant effects of exercise on scapular position and motion both in SIS patients and in asymptomatic individuals. However, their methodologic quality was debatable. Therefore, there was conflicting evidence for the effect of exercise on scapular dyskinesis.

CONCLUSION

There is a lack of evidence for beneficial effects of exercise in improving scapular position and motion in individuals with scapular dyskinesis. However, exercise is beneficial in reducing pain and disability in individuals with SIS.

Scapula Dyskinesis: A Review of Current Concepts and Evaluation of Assessment Tools

Scapula dyskinesis is prevalent in athletes conducting forceful overhead movements. This review summarizes our current understanding of the condition and evaluates the different options for assessing dyskinesis. Current methods for assessing scapula dyskinesis involve clinical observations, three-dimensional kinematics and three-dimensional wing computer tomography. Clinical observation is the most pragmatic method for assessing dyskinesis yielding inter-rater agreement of 79% and sensitivity of 76%. Similar sensitivities have been recorded using three-dimensional kinematics. Three-dimensional wing computer tomography has yielded a near-perfect interclass correlation coefficient of 0.972 when used to assess dyskinesis. Three-dimensional wing computer tomography, given its expense, low availability, and levels of irradiation, should be reserved for high-performance athletes where detailed assessments need to be made to aid rehabilitation. Observational assessments should remain the main modality used for general assessment.

Scapular Kinematics by Sex Across Elevation Planes

Scapular kinematics are important indicators of dyskinesis, often suggesting underlying shoulder pathology, but the influence of sex is unknown. This study's objective was to examine scapular kinematics in healthy males and females. Positions of surface-mounted reflective markers were tracked during arm elevation movements in 0°/30°/40°/60°/90°/120° planes. Scapulothoracic rotations (protraction/retraction, medial/lateral rotation, posterior/anterior tilt) were calculated. ANOVA analysis evaluated main and interaction effects of sex, plane, phase, and elevation angle. Males and females had similar protraction/retraction and medial/lateral rotation kinematics; mean sex-related peak angle differences were 2.5°, 1.8° (raise [concentric]), respectively, and 2.9°, 2.7° (lower [eccentric]), respectively. Largest sex differences for mean peak angle occurred for posterior/anterior tilt at higher elevation angles (raise, 8.4°; lower, 8.5°). Elevation, plane, and phase were main effects for all scapular rotations (P < .001). Sex was not a main effect for any rotations. Sex × elevation interactions influenced protraction/retraction (P < .001) and posterior/anterior tilt (P < .001). Sex × plane (P ≤ .01) and sex × phase (P ≤ .002) interactions influenced all rotations. Lower posterior tilt for females compared to males at higher elevation angles could relate to higher female shoulder pathology incidence. Sex, plane, and phase are necessary components of uninjured scapular kinematics. Sex-specific differences provide insight into potential shoulder pathology etiology. These data provide a benchmark to assess pathological populations.

The Effectiveness of Exercise Therapy on Scapular Position and Motion in Individuals With Scapular Dyskinesis: Systematic Review Protocol

Background

Scapular dyskinesis is an alteration in normal scapular position and motion. Some researchers believe that altered kinematics of the scapula subsequent to dysfunction or weakness of scapular stabilizing muscles contributes to impingement syndrome. Scapular muscle exercises are included in the rehabilitation of patients with subacromial impingement syndrome and scapular dyskinesis because the muscular system is one of the major contributors of scapular positioning both at rest and during shoulder movement, but there is considerable uncertainty relating to the relative effectiveness of such approaches on changing scapular position and motion.

Objective

The aim of this systematic review protocol is to evaluate the effectiveness of exercise therapy on scapular position and motion in individuals with scapular dyskinesis.

Methods

A systematic review will be conducted using PubMed, Scopus, Web of Science, Elsevier, Ovid, ProQuest, Physiotherapy Evidence Database, and Cochrane Library. The reference lists of articles, other reviews, gray literature, and key journals will be searched for relevant articles. Clinical trials reporting the effect of therapeutic exercises (scapular strengthening exercise, scapular stabilization exercise, scapular muscle stretching) with the aims of changing scapular position and motion in individuals with scapular dyskinesis will be included. Two independent reviewers will select studies, extract data, and assess the quality of primary studies. Any disagreement during the selection of studies will be discussed and decided by the whole team.

Results

This systematic review began in December 2016 and is currently in progress. The findings will be synthesized to determine the effectiveness of recommended therapeutic exercise on scapular position and motion in individuals with scapular dyskinesis.

Conclusions

This is the first systematic review protocol aiming to assess the effectiveness of exercise therapy in individuals with scapular dyskinesis. The systematic review doesn’t require ethics approval because all data used will be provided from published documents. The results of this study will be published in a peer-reviewed journal.

Trial Registration

PROSPERO CRD42017053923; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=53923 (Archived by WebCite at http://www.webcitation.org/6uzq32T02)

MRI for the diagnosis of scapular dyskinesis: a report of two cases

Scapular dyskinesis describes the altered position of the scapula and/or abnormal movements of the scapulothoracic joint. It is caused by bony anatomical variations, bursitis, tumors, and muscular pathological conditions including loss of innervation and fibrosis. Scapular dyskinesis is just as often subclinical as it is symptomatic, and as the periscapular anatomical changes may not result in patient symptoms, a precise diagnosis of the etiology and pathophysiology has been a challenge. Scapular bony prominence is a common etiology of scapular dyskinesis, but does not always result in morbidity. We report a case of a 39-year-old man in whom an extensive MRI with fluid-sensitive imaging sequences covering the whole of the scapula was beneficial in diagnosing the inflammation adjacent to the bony deformity, which confirmed the etiology of scapular dyskinesis. Furthermore, in a 41-year old man without any anatomical variances, a similar MRI showed inflammation at the subscapular fossa that suggested altered scapular kinematics. An arthroscopic debridement of the lesion improved the symptoms. MRI in conjunction with plain radiographs, CT and physical examination enabled a precise diagnosis of the etiology. Fluid-sensitive MR images are important in defining the presence of inflammation, and are beneficial in determining the pathological significance of findings through other diagnostic measures.

Shoulder Injuries in the Overhead Throwing Athlete

The overhead pitching motion is a coordinated sequence of movements that subjects the shoulder to extreme forces. The ultimate goal of this complex, dynamic activity is to generate high ball velocity and accuracy. In doing so, repetitive throwing can cause adaptive and pathologic changes in the thrower's shoulder. This article reviews the relevant shoulder anatomy, the kinetic chain, and throwing mechanics, as well as common shoulder injuries and surgical options for the treating orthopedic surgeon.

The Influence of Test Positions on Clinical Assessment for Scapular Dyskinesis

BACKGROUND

Appropriate evaluation of scapular dyskinesis is essential for therapeutic strategies. Although the current visual-based assessment is rapid and practical, the reliability of this method is unsatisfactory. It is necessary to adequately understand the conditions of assessment to maximize the benefit of therapeutic interventions.

OBJECTIVE

To explore the influence of different test positions on clinical assessment for scapular dyskinesis.

DESIGN

Observational study.

SETTING

University rehabilitation department.

PATIENTS

A total of 102 subjects diagnosed with unilateral shoulder disorder were recruited from among rehabilitation outpatients from November 2015 to February 2016.

METHODS

Two experienced raters categorized the subjects' scapular movement pattern according to Kibler et al classification by the vision-palpation method at 4 test positions (at rest, and the end range of elevation in the sagittal, scapular, and coronal planes).

MAIN OUTCOME MEASUREMENTS

The overall prevalence of scapular dyskinesis, the distribution of types, and the reproducibility of types at the 4 test positions were analyzed.

RESULTS

The overall prevalence of scapular dyskinesis was 90.08%, and the highest frequency was found at the resting position. Type III was the most common type in our sample. In reproducibility analysis, 21.57% of subjects presented with the same type at any position, and 75.49% of subjects presented with 2 types.

CONCLUSIONS

Scapular dyskinesis in individuals with shoulder disorder showed a high prevalence, especially at the resting position. More than 1 type of scapular pattern would be present if assessed at different positions. This study indicates that test positions can affect the results of scapular dyskinesis assessment, and that the resting position should primarily be applied.

LEVEL OF EVIDENCE

III.

Are chronic neck pain, scapular dyskinesis and altered scapulothoracic muscle activity interrelated?: A case-control study with surface and fine-wire EMG

OBJECTIVES

The function of the scapula is important in normal neck function and might be disturbed in patients with neck pain. The surrounding muscular system is important for the function of the scapula. To date, it is not clear if patients with idiopathic neck pain show altered activity of these scapulothoracic muscles. Therefore, the objective of this study was to investigate differences in deeper and superficial lying scapulothoracic muscle activity between patients with idiopathic neck pain and healthy controls during arm elevation, and to identify the influence of scapular dyskinesis on muscle activity.

METHODS

Scapular dyskinesis was rated with the yes/no method. The deeper lying (Levator Scapulae, Pectoralis Minor (Pm) and Rhomboid major) and superficial lying (Trapezius and Serratus Anterior) scapulothoracic muscles' activity was investigated with fine-wire and surface EMG, respectively, in 19 female subjects with idiopathic neck pain (age 28.3±10.1years, average duration of neck pain 45.6±36.3months) and 19 female healthy control subjects (age 29.3±11.7years) while performing scaption and towel wall slide. Possible interactions or differences between subject groups, scapular dyskinesis groups or phases of the task were studied with a linear mixed model.

RESULTS

Higher Pm activity during the towel wallslide (p=0.024, mean difference 8.8±3.3% MVIC) was shown in patients with idiopathic neck pain in comparison with healthy controls. For the MT, a significant group∗dyskinesis interaction effect was found during scaption which revealed that patients with neck pain and scapular dyskinesis showed lower Middle Trapezius (MT) activity in comparison with healthy controls with scapular dyskinesis (p=0.029, mean difference 5.1±2.2% MVIC).

CONCLUSIONS

In the presence of idiopathic neck pain, higher Pm activity during the towel wallslide was found. Patients with neck pain and scapular dyskinesis showed lower MT activity in comparison with healthy controls with scapular dyskinesis during scaption. Scapular dyskinesis did not have a significant influence on scapulothoracic muscle activity.

Adaptation of muscle activity in scapular dyskinesis test for collegiate baseball players

BACKGROUND

The characteristics of scapular muscle activities in elevation and descent exercises have yet to be elucidated to assess scapular dyskinesis. The purpose of this study was to identify the adaptation of electromyograph (EMG) activities of the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and anterior deltoid (AD) muscles with different weight loads in flexion (FLX) and abduction (ABD) in collegiate baseball players.

MATERIALS AND METHODS

Twenty eight individuals, including 13 pitchers, were tested. Normalized EMG signals for the UT, LT, SA, AD muscle of the both the dominant (DOM) and nondominant (NON) side were blocked at every 1 second during each of the exercises. A 3-way repeated analysis of variance design was used to identify differences in the mean values between DOM and NON and between FLX and ABD for DOM.

RESULTS

The mean EMG value of the UT in the DOM was significantly less than that of the NON for all joint angles (P < .01), whereas the mean EMG value of the LT in the DOM was significantly greater than that of the NON (P < .01). In contrast, no difference in the SA EMG activity was determined between DOM and NON. However, the mean EMG value of SA in FLX was significantly greater than in ABD (P < .01).

CONCLUSION

This study identified an apparent adaptation of scapular muscle activities in the currently advocated scapular dyskinesis test for healthy active overhead athletes who are vulnerable to shoulder pathologies.

Prevalence of Scapular Dyskinesis in Overhead and Nonoverhead Athletes: A Systematic Review

Background:

Scapular dyskinesis, or abnormal dynamic scapular control, is a condition that is commonly associated with shoulder pathology but is also present in asymptomatic individuals. Literature varies on whether it represents a cause or symptom of shoulder pathology, but it is believed to be a risk factor for further injury. Clinical identification focuses on visual observation and examination maneuvers. Treatment of altered scapular motion has been shown to improve shoulder symptoms. It is thought to be more common in overhead athletes due to their reliance on unilateral upper extremity function but the incidence within nonoverhead athletes is unknown.

Hypothesis:

Overhead athletes will have a greater prevalence of scapular dyskinesis when compared with nonoverhead athletes.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

After PROSPERO registration, a systematic review was performed using PRISMA guidelines through the PubMed database looking for studies published before October 2014. All studies containing the search terms scapular, scapulothoracic, dyskinesis, dyskinesia, shoulder athlete, or overhead athlete were included. Studies that did not include prevalence data for scapular dyskinesis were excluded. Study methodological quality was evaluated using the modified Coleman methodology score. Descriptive statistics and 2-proportion 2-tailed z-tests were used to compare the reported prevalence of scapular dyskinesis between overhead and nonoverhead athletes.

Results:

Twelve studies were analyzed including 1401 athletes (1257 overhead and 144 nonoverhead; mean age, 24.4 ± 7.1 years; 78% men). All the studies were evidence level 2 (33%) or level 3 (67%). The reported prevalence of scapular dyskinesis was significantly (P < .0001) higher in overhead athletes (61%) compared with nonoverhead athletes (33%).

Conclusion:

Scapular dyskinesis was found to have a greater reported prevalence (61%) in overhead athletes compared with nonoverhead athletes (33%).

Clinical Relevance:

Prevalence data for scapular dyskinesis are scarce within the literature. Information on the reported prevalence, laterality, and association with the dominant extremity will allow for better allocation of diagnostic and therapeutic interventions. Recognition and treatment will help athletes to optimize functional performance and decrease the risk of further shoulder injury.