Scapulothoracic Dyskinesis: A Concept Review

Abstract

Purpose of Review

Scapulothoracic dyskinesis (SD) occurs when there is a noticeable disruption in typical position and motion of the scapula, which can result in debilitating pain. The purpose of this review is to describe the current knowledge regarding the diagnosis and management of scapulothoracic dyskinesis by providing an evidence-based overview of clinical exams and treatment modalities available for orthopedic surgeons and provide insight into which treatment modalities require further investigation.

Recent Findings

SD is highly prevalent in athletes, particularly those participating in overhead activities (e.g., baseball, tennis, and swimming) and can coexist with several shoulder pathologies. A holistic approach in the diagnosis of SD has been supported in the literature; however, it is important to recognize that diagnosis is currently limited to the absence of a quantitative SD clinical assessment. The main goal of the treatment of SD is to regain proper scapular positioning and dynamics. The standard of care for the management of SD is conservative interventions aimed at optimizing scapular kinematics. Surgical intervention is only considered in the presence of concomitant pathology requiring surgery.

Summary

Due to the complexity of coordinated movement of the shoulder girdle, recent literature has begun to move away from the use of traditional orthopedic tests, in favor of a more system-based approach for the diagnosis of SD. We present a concise review of clinical exams and treatment modalities available for orthopedic surgeons in the management of SD.

Introduction

The shoulder girdle is critical for the motion of the upper extremity as several joints and muscles work in concert to produce distinct movement patterns. Most of these movements occur via coordinated rotational and translational movement [1]. The scapula maintains a functionally and anatomically significant articulation to the humerus and is critical for the proper movement and anchorage of the arm to the trunk. The functional relationship between the scapula and humerus is referred to as glenohumeral or scapulohumeral rhythm, and this concept is paramount for efficient function of the shoulder [2]. Scapulothoracic dyskinesis (SD) occurs when there is a noticeable disruption in typical position and motion of the scapula which can result in atypical and inefficient motions of the arm and shoulder [3, 4]. SD typically occurs secondary to numerous separate pathologies of the shoulder including injury of the acromioclavicular (AC) joint, rotator cuff tear, clavicular fracture, shoulder impingement, multidirectional instability, and labral injury [5–10, 11••, 12]. Successful clinical evaluation of shoulder pathology is needed when assessing dysregulation in scapular motion and position [13]. Based on underlying glenohumeral pathology, appropriate treatment modalities may be considered [13, 14].

Scapular Motion and Associated Musculature

Due to the lack of a bony articulation between the thorax and scapula, scapular motion can be defined by a number of directional motions. The accompanying motions involve elevation, depression, protraction, retraction, and upward/downward rotation and allow for effective propagation of movements carried out by the arm and shoulder in relation to the trunk [3]. It must be noted that elevation requires coordinated flexion and abduction, while depression requires coordinated adduction. Focusing on scapular motion itself, it has been widely accepted that rotational motions occur across three planes (coronal, sagittal, and transverse) and translational motions occur across two planes [15]. Upward and downward rotation occurs across the coronal plane while internal and external rotations relate to rotation through the transverse plane [16]. The third, briefly mentioned, sagittal plane involves the important rotational motions related to posterior and anterior tilt [16]. The proper execution of these motions is necessary for efficient scapular motion. Scapular translational motions involve sliding of the scapula across the thorax in different combinations of motion [17]. These motions can occur via a mediolateral pathway or by an inferior to superior pathway [15]. The sets of periscapular musculature that carry out these motions include the trapezii, serratus anterior, rhomboids, levator scapulae, and the pectoralis minor [18] (Table 1).

Table 1.

Periscapular musculature

Muscle	Origin	Insertion	Function
Trapezius	Medial third nuchal line, ligamentum nuchae, spinal process and through T12	Lower acromion, lateral third posterior border of clavicle, scapular spine	Upward rotation, medial translation, and external rotation of scapula
Serratus anterior	Superior segment: ribs 1-2; middle segment: ribs 3-4; inferior segment: ribs 5–9	Superior segment: superomedial scapula; middle segment: anteromedial scapular border; inferior segment: inferomedial scapula	External rotation of shoulder girdle, upward rotation
Rhomboid	Major: supraspinous process of T2-T5 of spine; minor: supraspinous process of C7-T1	Major: inferomedial border of scapula; minor: posteromedial border of the scapula	Scapular retraction and downward rotation
Levator scapulae	Transverse process C1-C4	Superior vertebral border of scapula	Elevation and downward rotation of scapula
Pectoralis minor	3rd–5th ribs	Medial border and superior surface of coracoid process	Depression and protraction of scapula

The trapezius is a primary stabilizer of the scapula and contains three specific regional components—superior, middle, and inferior [18, 19]. Retraction and abduction of the scapula, required for the elevation of the arm, are heavily influenced by the activation of the trapezius muscle [16, 19, 20]. More specifically, activation of the superior portions of the trapezius results in upward rotation of the scapula, while activation of the lower and medial portions contributes to medial translation and external rotation [20]. The lower trapezius stabilizes the arm during complete elevation and throughout its descent from that position [16]. Serratus anterior is also required for efficient scapulothoracic motion. Like the trapezius, it contains superior, middle, and inferior segments. It maintains the scapula flush to the thoracic cage [16] which prevents excess internal rotation of the scapula during movements in which the arm is stretched outward in front of the body [19]. Biomechanically, the serratus anterior aids in external rotation of the shoulder girdle. Additionally, through action of the inferior portion of the serratus anterior, upward rotation is possible [20]. Proper motion and stability of the scapula through the coronal plane are therefore exceptionally dependent on the serratus anterior. It should be noted that both the serratus anterior and the trapezius work largely in unison to produce upward rotation and posterior tilt of the scapula [16]. Rhomboid musculature includes the rhomboid major and minor, both of which aid trapezius’s functions and play an important role in mediolateral translations of the scapula [16]. Together, the rhomboid muscles work along with the middle segment of the trapezius to aid in stability and mobility of the scapula [14, 16].

While previous literature has described scapulohumeral rhythm as a 2:1 ratio of motion between the humerus and scapula, whereby for every 2 degrees of humeral flexion/abduction corresponding to 1 degree of scapular upward rotation [17], recent studies have shown that this ratio varies greatly. Theoretically, if a patient aims to achieve 180 degrees in relation to the trunk of the body, an observed 120 degrees would occur in the humerus and 60 degrees of upward rotation in the scapula. A study by Ludewig et al. aimed to more precisely quantify these findings. They used indwelling bone pins to analyze the upward rotation, internal rotation, and anterior tilt of the scapula as it relates to the thorax of the torso suggested that the scapula in resting position maintained about 5.4 degrees of upward rotation, 41.1 degrees of internal rotation, and about 13.5 degrees of anterior tilt [21]. The same study additionally analyzed the scapulohumeral rhythm of several motions including elevation, scaption (defined as scapular plane elevation), and abduction. The results of this portion of the study expressed ratio values of 2.4:1 for flexion, 2.2:1 during scaption, and 2.1:1 during abduction [21]. Another study conducted by Giphart et al. involved the use of a dynamic biplane fluoroscopy system to determine 3-dimensional (3-D) position of the humerus and scapula. The study found different scapulohumeral rhythm ratios during different motions performed by the subjects. Respectively, a ratio of about 2.0:1 was observed during abduction, a ratio of about 1.6:1 was observed during scaption, and an approximate 1.1:1 ratio was observed during forward flexion elevation [22]. These findings suggested that scapular motion is a very complex, dynamic entity that activates different muscles at different phases of motion.

SD is defined as a deviation from normal positioning or motion of the scapula [4]. Accompanying clinical factors may include increased prominence of the medial border and inferior angle of the scapula, premature scapular elevation with insufficient upward rotation, and deficient downward rotation when lowering the arm [4]. Weakness of the periscapular muscles is thought to be the progenitor of SD [13]. Specifically, an observed overactivation of the superior trapezius may occur in combination with significantly reduced activation of the inferior portions of the trapezius and serratus anterior [13]. It must be noted that although there is no true direct correlation between shoulder pathologies and SD, studies have reported that an approximate 68% to 100% of individuals suffering from a known shoulder pathology also present with SD [6–8, 23].

Epidemiology

Complaints of neck and shoulder pain are common among the general population. Studies have suggested prevalence between 6.7% and 66.7% [13, 24, 25, 26•, 27]. SD is common in patients complaining of neck and shoulder pain, and they often present with muscular weakness and shoulder instability [14]. SD is associated with various shoulder diseases, including rotator cuff pathology, glenohumeral instability, impingement syndromes, and labral tears [5–10, 11••, 12]. Studies have suggested that SD is quite prevalent in the general population and is not restricted to individuals experiencing shoulder pain [2, 26•]. In one study involving 40 healthy college aged participants, 68% of the subjects presented with SD [26•].

The athletic population is at a higher risk for the development of shoulder injuries [13]. Those that engage in overhead sports (baseball, tennis, volleyball, handball, swimming, etc.) are at a particularly high risk [28]. A systematic review by Burn et al. examining the prevalence of SD among athletes reported a 54.5% prevalence of SD for athletes engaged in overhead sports and a prevalence rate of 33.3% for athletes competing in non-overhead sports [28]. Athletes with SD have a 43% greater risk of developing shoulder pain vs. athletes without such condition [29•]. Additionally, excessive thoracic kyphosis and cervical lordosis alter the resting position of the scapula and make individuals prone to the development of SD [14, 30]. Athletes are particularly susceptible to these types of changes. Certain training and exercise regiments can create a core muscle imbalance that alters spinal curvature and creates tension in the soft tissues [2].

Another high-risk group for the development of shoulder and neck injuries are individuals who spend prolonged periods of time using personal computers [2, 13, 31]. Poor sitting posture has been implicated. Literature suggests that the dominant extremity is most often implicated in SD and shoulder injury. This is likely due to overuse, muscle asymmetry, and differences in range of motion (ROM) [27, 32, 33]. Furthermore, a study by Picco and colleagues evaluating scapular kinematics found that healthy females exhibit lower posterior tilt compared to healthy males at high elevation angles, predisposing females to a higher incidence of SD and shoulder pathology [34•]. Other risk factors for shoulder pain include obesity and older age [35, 36].

Clinical Evaluation

Presently, there is no reliable clinical method to diagnose SD. Observing shoulder motion with a high degree of inter- and intra-observer reliability in a clinical setting has been proven to be difficult [2]. One of the issues in clinical evaluation has to do with effective measurement of scapular motion. The 3-D kinematics of scapular motion in combination with the high relative amount of soft tissue surrounding the scapula itself presents a hurdle to overcome in clinical evaluation [14]. Several clinical assessments have been developed in an attempt to diagnose SD (Table 2.).

Table 2.

Clinical assessments of scapulothoracic dyskinesis

Assessment	Methodology
McClure et al. visual assessment	Visual classification based on degree of dyskinesis: normal, subtle, obvious
Uhl et al. visual assessment	Visual classification based on presence or absence of scapulothoracic dyskinesis
Kibler et al. visual assessment	Based on 4 movement patterns: pattern I—inferomedial scapular border; pattern II—medial scapular border; pattern III—superior scapular border; pattern IV—symmetric
Scapular assistance test	Examiner assists patient in upward rotation and posterior tilt during shoulder activation. Test is positive if ROM is increased or pain is reduced
Scapular retraction test	Examiner assists with active elevation by applying external rotation and posterior tilt to the scapula. Test is positive if pain is reduced during exam
Lateral scapular slide test	Examiner measures distance from superior angle of scapula, scapular spine, and inferior angle of scapula to the thoracic spine with arm place in three different positions. Test is positive if measurement variation exceeds 1.5 cm
Isometric scapular pinch test	Patient is asked to retract scapula together as much as possible and to hold the isometric contraction for 20 seconds. Test is positive if burning sensation is present
Wall pushup test	Patient is asked to perform 20 pushups. Test is positive if wing scapula is present

SD can be graded using a number of criteria. McClure et al. utilized classification of SD by three degrees of dyskinesis—normal, subtle, or obvious [37]. A study by Uhl et al. utilized visual assessment to classify patients with the presence or absence of SD [38]. Finally, a third study by Kibler et al. categorized SD into 4 separate movement patterns. Respectively, these movement patterns include inferomedial scapular border pattern (pattern I), medial scapular border pattern (pattern II), superior scapular border pattern (pattern III), and symmetric pattern (pattern IV) [38, 39]. Pattern I presents with a visible and palpable prominence of the inferior angle of the scapula while pattern II presents with a prominence of the medial border [38, 39]. Pattern III relates to deficient or unrestrained elevation and upward rotation of the scapula as well as prominence of the superomedial border, and pattern IV presents normal, symmetric motion, and position [38, 39]. Combinations of these patterns may exist as mixed patterns [38, 39]. It was suggested by the authors of these studies, however, that the low overall interrater reliability of these findings lacked sufficient support for effective use of this method in clinical evaluation of SD. Visual assessments maintain a degree of limitations in a clinical setting, and thus, other tests must be implemented [14].

Several physical exam maneuvers can be performed to aid in the diagnosis of SD. These include the scapular assistance test (SAT), scapular retraction test (SRT), lateral scapular slide test (LSST), isometric scapular pinch test, and the wall pushup test. When performing the SAT, it is critical to assess a patient’s baseline active ROM and pain level prior to starting the test [40•]. Following the baseline assessment, scapular kinematics are assisted by manually providing the scapula with upward rotation while the patient elevates the upper extremity [40•]. A positive test is indicated by increased ROM or reduced pain [41]. In addition to identifying presence of SD, SAT is capable of aiding in the identification of both impingement of the shoulder and strength degradation of the rotator cuff muscles [41].

SRT primarily focus on testing the graded strength of the supraspinatus muscle of the rotator cuff and evaluating injuries of the labrum. After assessing baseline line active ROM and pain in the patient, this exam is performed by applying external rotation and a posterior tilt to the scapula while the patient performs an isometric contraction against downward resistance placed on the arm from the empty can position [42, 43]. A positive test for SRT would be indicated by increased strength or reduced pain [42–44]. Positive findings in the SRT assessment may indicate the presence of internal impingement after injury to the labrum (but an intact rotator cuff) [42, 43]. A negative SRT showing continued weakness of the supraspinatus after aided retraction may be indicative of a full-thickness rotator cuff tear [43]. For this reason, this test is commonly performed in conjunction with the Neer’s, Jobe’s, and Hawkin–Kennedy’s tests.

LSST is performed by assessing excessive movement in the scapula in relationship to thoracic spine. Three measurements are taken from the spine of the scapulae to T2/T3, from the inferior angle of the scapulae to T7/T9, and from the superior angle of the scapulae to T2. These measurements are then recorded three times in the following positions while standing: arms relaxed and resting on sides, hands on waist with thumbs pointed posteriorly, and maximal internal rotation with arms abducted at 90 degrees. The presence of more than 1.5 cm in measurement variation is indicative of a positive exam [45, 46].

The isometric scapular pinch test and wall pushup test both evaluate pain and muscular endurance. An isometric scapular pinch test is performed by asking the patient to actively retract scapulae together as much as possible and to hold that position for 20 seconds. A positive test is noted if a burning sensation is present after 15–20 seconds. The wall pushup test evaluates SD by assessing for weakness in musculature surrounding the scapula, primarily the serratus anterior [47–49]. The patient is asked to perform 20 wall pushups. A positive test is noted if muscular fatigue produces visible medial scapular winging.

Due to the complexity of coordinated movement of the shoulder girdle, recent literature has begun to move away from the use of traditional orthopedic tests, in favor of a more system-based approach [50]. The shoulder symptom modification procedure (SSMP) has proposed the use of four maneuvers that are applied to the patient while they are performing movements that would worsen pain [51]. These four maneuvers consist of a humeral head procedure, in which the position of the humeral head was in relation to the glenoid fossa, scapular position procedure, in which changes are made to the scapular position, cervical and thoracic region procedures, in which positions of possible referred pain to the shoulder are investigated, and lastly thoracic kyphosis, in which taping is applied to the thoracic region to evaluate pain reduction.

While a holistic approach in the diagnosis of SD has been supported in the literature, it is important to recognize that diagnosis is currently limited to the absence of a quantitative SD clinical assessment [52]. Future studies should evaluate the application of advanced 3D motion capture and the computational analysis offered through machine learning and artificial intelligence (AI) to develop new imaging modalities for the assessment of SD. The use of pattern recognition has been demonstrated previously to be able to recognize disease characteristic that would otherwise be unappreciable by the naked eye [53]. Evaluation of 3D imaging by AI may provide new insight in the diagnostic criteria for SD.

Implication on Shoulder Pathology

Shoulder Impingement

Shoulder impingement is one of most common shoulder pathologies. It is often characterized by entrapment of the soft tissues when the arm is raised resulting in pain [54]. A negative change in the diameter of the subacromial space has been heavily linked as a causative agent to shoulder impingement [4, 32, 54]. SD has often been observed in conjunction with shoulder impingement [4]. A disruption in scapulohumeral rhythm occurs in the presence of shoulder impingement producing SD via altered motion, specifically increased protraction which can narrow the subacromial space [4, 55]. These abnormal motions are characterized by decrease in upward rotation, increase in anterior tilt, and overactivated and rapid internal rotation [4, 55].

The observed SD accompanying shoulder impingement maintains some connection to inefficient coordination and activation between several periscapular muscles [4]. Excessive activation of the superior trapezius is accompanied by deficient activation of both the inferior trapezius and serratus anterior [4, 54, 55]. Visible findings associated with methods described earlier by Kibler et al. express the presence of a type III classification of dyskinesis [4, 39].

Acromioclavicular (AC) Injury

Injury to the AC joint is another common shoulder pathology with links to SD. AC joint injury typically involves separation, subluxation, or dislocation resulting from a detachment of the scapula from the clavicle [56]. SD is related to AC joint injury by means of an occurrence of abnormal positioning of the scapula [4]. As a result of AC injury, the scapula becomes downwardly displaced and susceptible to increased protraction and internal rotation [4, 57]. Specific increases in upward rotation of the clavicle and internal rotation occur as well as decreases in posterior clavicular rotation and external rotation of the scapula [57]. The separation and alteration of normal scapular position in relation to the humerus and clavicle lead to significant impairment of normal scapulohumeral rhythm as well as reduced stability, mobility, and rotator cuff strength [4]. Grade II and III separations of the AC joint are often severe enough to require surgical intervention for repair in order to reintroduce proper motion [4, 57].

Clavicular Fracture

The clavicle acts as a bony strut for the glenohumeral joint as it attaches the upper extremity to the axial skeleton. A clavicle fracture can lead to malunion which, in turn, negatively impacts the functional properties of the clavicle as a strut [4]. Decreases in range of motion, incorrect positioning, and improper mobility often follow, and this impaired function may often lead to SD [4, 58]. This results in an increase in protraction of the scapula, leading to dysfunction and reduced strength of the rotator cuff [4]. Surgery may be required to correct and has been found to reduce the prevalence of SD in patients with clavicle fractures [58].

Rotator Cuff Disease

Rotator cuff pathology is a leading cause of shoulder pain and dysfunction [59]. Muscle weakness or tear of the encompassing muscles may be observed due to several factors including direct injury, disuse atrophy, or inhibition of the muscle to guard from pain [4]. Excess scapular protraction may occur as a result of SD, which inevitably leads to reductions in overall strength of the rotator cuff [4, 41, 59]. Both SRT and SAT assessments can determine whether loss of strength in the rotator cuff is observed. The SRT assessment is particularly useful in determining whether a full-thickness rotator cuff tear has occurred [43]. This test accomplishes this by assessing whether assistance with retraction of the scapula improves rotator cuff strength [43]. The visual assessment of the scapula in association with the abnormal position and motion in disease of the rotator cuff reveals a type II classification pattern of SD [4, 39].

Multidirectional Instability

Multidirectional instability of the shoulder is characterized by laxness of the glenohumeral joint contributing to reduced stability and improper kinematics [60]. SD commonly coexists with multidirectional instability and results in the increased protraction of the scapula [4]. Several studies have postulated that the aforementioned excess scapular protraction could be attributed to overactivation of the latissimus dorsi and pectoralis minor combined with the decreased activation of the inferior segment of the trapezius and serratus anterior [4, 61–63]. This excess protraction ultimately permits the humeral head to shift inferiorly out of the glenoid socket producing the instability [61, 64, 65].

Labral Injury (Superior Labral Anterior/Posterior (SLAP))

The labrum aids in stabilization of the glenohumeral joint [60]. Injury to the labrum and the presence of a SLAP tear can therefore be attributed to both decreased stability of the shoulder and disruption of normal scapulohumeral rhythm [4, 60, 66, 67]. It has been observed that the presence of deficient internal rotation occurs with SLAP tears and labral injury thus leading to improper scapulohumeral kinematics [68]. The altered motion, stability, and position lead to excess protraction of the scapula indicating the presence of SD.

Treatment Modalities

Treatment has been focused on restoring normal scapular kinematics through exercise and manual therapy techniques [13]. The main goal of the treatment of SD is to regain proper scapular positioning and dynamics. The standard of care for the management of SD is conservative interventions aimed at optimizing scapular kinematics, surgical intervention is only considered in the presence of concomitant pathology requiring surgery [14].

Conservative treatment can be divided into two subcategories: exercises aimed at improving flexibility, and exercises focused on increasing scapular stabilization [14]. Combining these two approaches leads to decreased scapular traction and optimizes scapular kinematics [14]. Proper management of SD requires determining if SD is secondary to lack of muscle performance or loss of flexibility in the surrounding soft tissue. If the underlying cause is due to lack of muscle control, the patient will be advised to partake in muscle strengthening exercises, along with muscle control exercises. This will lead to improved proprioception and muscle strength, both of which aid in increasing the stability of the scapula [13, 69••]. Two major targets of strength training are the trapezius muscles and the serratus anterior. The lower trapezius aids in stabilization of scapular positioning, while the serratus anterior determines scapular external rotation and posterior tilt [14]. Exercises beneficial to increasing muscle strength and stability include pushups on a stable surface, which have been shown to increase the strength and control of the serratus anterior [14]. Shoulder shrugs with an upward rotation are recommended to activate and strengthen the lower and upper trapezius [13, 14]. It must be noted that for maximal benefit, the patient must first obtain active control of the muscles supporting the scapula. Once the patient has control of the targeted muscles, focus may be switched to strength training with maintaining proper form and active control of the targeted muscles [13]. In a randomized control trial of twenty-eight patients with SD, Nowotny et al. evaluated the treatment with an exercise program versus massage therapy at 6-week follow-up [69••]. A total of 13 patients received massage therapy, and 15 received an exercise program. Visual analog pain score, Quick Dash score, SICK scapula rating scale, and hand press-up test were all collected before and after therapy. Patients in both cohorts experienced significant reductions in VAS scores (exercise (p=0.007) vs. massage (p=0.004)), while the scores for Quick Dash (p=0.001), SICK scapula rating scale (p=0.003), and hand press up test (p=0.026) were only significantly reduced in the exercise cohort. Their findings illustrate that scapular focused exercises can result in significant improvements in shoulder function.

If the patient’s SD stems from a lack of soft tissue flexibility, therapy will be more focused on stretching of the scapular muscles and the glenohumeral muscles/capsule. Stretching and mobilization of the joint allow for the increased range of motion and may alleviate the pain caused by the stiff soft tissue structures [13]. Scapular muscles targeted during stretching include the pectoralis minor, levator scapulae, and rhomboids. On the level of the glenohumeral muscles, the posterior capsule, infraspinatus, and latissimus dorsi are the important structures to be stretched [13, 14]. Specific stretches, such as arm abduction from 90 degrees to 150 degrees, are useful in increasing flexibility of the pectoralis minor, along with increasing the external rotation and posterior tilt of the scapula [14].

A combination of the two subcategories mentioned above has been shown to lead to improved clinical outcomes. Shirzadi et al. performed a randomized clinical trial comparing physical therapy alone to scapulothoracic mobilization plus therapy in patients with mechanical neck pain. Their investigation found that scapulothoracic mobilization paired with physical therapy was superior to patients only receiving physical therapy alone. A reduction in visual analog pain score and an increase grip strength in newtons were observed after the first session (p=0.01) and fifth session (p=0.001) [70••]. Merolla et al. conducted a prospective study of 31 professional volleyball players with scapular dyskinesis and examined the effect of musculature training on isometric infraspinatus strength at 3- and 6-month follow-ups [71]. At both time points, there was a statistically significant increase in mean force of the infraspinatus (p<0.01 at 3 months and p<0.001 at 6 months). Patients did not see a reduction in pain scores at either time point (2.4 ± 1.8 and 2.6 ± 1.4, at 3 and 6 months, respectively). In a prospective case series of 24 patient with chronic acromioclavicular dislocation and scapular dyskinesis, Carbone and colleagues examined the effects of rehabilitation on shoulder function at 12-month follow-up [72]. Their study found that at 12-month follow-up scapular dyskinesis was not seen in 78.2%, and mean constant score and subjective shoulder value were increased by 85 points. When managing patients with SD, the literature supports the use of physical therapy focused on restoring normal scapular kinematics and improving patient outcomes through exercise and manual therapy techniques.

Closing Remarks

SD is highly related to scapular motion and position. It is associated with several shoulder pathologies. Due to significant variation in classification systems and lack of standardized diagnostic methods, it remains difficult to evaluate SD in the clinical setting. The gold standard for treatment is targeted physical therapy. Continued research and implementation of different modalities of diagnosis and treatment may be beneficial in gaining a more complete understanding of this disorder.

Declarations

Ethics Approval and Consent to Participate

This project did not require review by the institutional review board. This article does not contain any studies with human or animal subjects performed by any of the authors.

Conflict of Interest

Kelechi R. Okoroha reports potential conflicts of interest from the following companies: Arthrex (grand and education), Smith & Nephew (education, travel, lodging), Pinnacle (education), Medwest Associates (education), Wright Medical Technology (travel and lodging), and Stryker Corporation (travel and lodging). Toufic R. Jildeh, Daisy A. Ference, Muhammad J. Abbas, and Eric X. Jiang declare that they have no conflict of interest.