Alterations in scapular kinematics in subjects with idiopathic loss of shoulder range of motion

The Clinical and Sonographic Features of Cervical Muscle Involvement in Patients with Frozen Shoulder: A Retrospective Study

Background/Objectives: Frozen shoulder is a common shoulder disorder that often places limitations on the range of motion of the shoulder. The disease may induce neck pain due to overuse of the neck muscle in an attempt to compensate for lack of shoulder movement. In clinical practice, swelling and inflammation of the scalene and levator scapulae may be detected via sonography in patients with frozen shoulder. The aim of this study was, therefore, to determine whether the involvement of the scalene complex or levator scapulae could compensate for the limited motion of the shoulder in patients with frozen shoulder. Methods: We retrospectively reviewed the medical records of 362 patients with unilateral frozen shoulder. These patients were divided into four groups depending on the involvement of the scalene complex or levator scapulae muscle. The range of motion of the shoulder-encompassing flexion, abduction, and external rotation-was measured with a goniometer. We also performed an ultrasound scan on each shoulder. The involvement of the scalene complex and levator scapulae muscle was also assessed via musculoskeletal ultrasound. Results: The range of motion of the shoulder in terms of flexion, abduction, external rotation, and total range of motion differed significantly between the four groups (p < 0.05). Patients in whom the scalene complex or levator scapulae muscle was involved demonstrated a significantly wider range of motion in different shoulder directions than patients without the involvement of those muscles (p < 0.05). Conclusions: A greater range of motion in the shoulder can be obtained through the activation of the scalene complex or levator scapulae muscle, which act to compensate for the lack of shoulder movement in patients with frozen shoulder. These two muscles showed thickening and hypoechoic changes upon sonography.

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.

Assessment of Bilateral Shoulder Range of Motion in Firefighter Trainees Using a Markerless Motion Capture System

The unpredictable environments firefighters face paired with biomechanically compromising shoulder movements, such as overhead and lifting movements, place this population at an increased risk for shoulder injury. The purpose of this study was to assess firefighter trainees’ bilateral shoulder range of motion (ROM) using the Dynamic Athletic Research Institute Motion system. Retrospective anthropometric and ROM data for 31 male firefighter trainees were analyzed. Firefighter trainees’ mean shoulder ROM for bilateral external rotation, internal rotation, and extension were lower than previously published values. External rotation demonstrated the lowest percentage of trainees within normal ROM (left—6.67%, right—16.67%). Noting the susceptibility of upper extremity injuries among firefighters, establishing baseline ROM measurements for reference may improve musculoskeletal evaluations, training interventions, and injury rehabilitation.

Comparison of shoulder muscle strength, shoulder range of motion and scapular motion in men with ankylosing spondylitis and healthy men: a case-controlled study

Background/Aims

Ankylosing spondylitis mainly affects the vertebral column, meaning that the assessment of the physical function of the upper extremity and scapulothoracic region in ankylosing spondylitis is often overlooked. Therefore, the aim of this study was to investigate shoulder muscle strength, shoulder active range of motion and three-dimensional scapular motion in patients with ankylosing spondylitis.

Methods

The study included 18 men with ankylosing spondylitis, and 16 age-matched typically healthy men as the control group. Muscle strength, active range of motion, and three-dimensional scapular motion were assessed with a digital hand-held dynamometer, an inclinometer, and an electromagnetic tracking device respectively.

Results

A decrease in shoulder flexion and abduction muscle strength on both the dominant side (P<0.001, P=0.001) and non-dominant side (P<0.001, P<0.001) was found in the ankylosing spondylitis group compared to the control group. A decrease in shoulder flexion, abduction, and external and internal rotation active range of motion on both the dominant side (P=0.001, P<0.001, P=0.015, P<0.001, respectively) and non-dominant side (P=0.001, P<0.001, P=0.017, P<0.001 respectively) was observed in the ankylosing spondylitis group. There was an increase in the upward rotation of the scapula on the non-dominant side at 30, 60, and 90° humeral elevations in the ankylosing spondylitis group compared to the control group (P=0.018, P=0.003, P=0.001 respectively). The other parameters of the scapular motion did not differ between groups (P>0.05).

Conclusions

This study showed that shoulder muscle strength and active range of motion were lower, and the upward rotation of the scapula was greater in men with ankylosing spondylitis compared to typically healthy men. The kinetics and kinematics parameters of the shoulder and scapula should be considered when assessing the physical function of patients with ankylosing spondylitis.

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

STUDY DESIGN

This is a systematic review.

INTRODUCTION

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

PURPOSE OF THE STUDY

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

METHOD

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

RESULTS

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

DISCUSSION

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

CONCLUSION

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

Clinical Management of Arthrofibrosis: State of the Art and Therapeutic Outlook

* Arthrofibrosis is a pathologic condition that is characterized by excessive periarticular scar-tissue formation. Arthrofibrosis may occur secondary to injury, surgical trauma, hemarthrosis, or infection, or it may occur idiopathically.* The pathogenesis of arthrofibrosis is incompletely understood but involves the dysregulation of normal reparative pathways, with transforming growth factor-beta (TGF-[beta]) as a principal mediator.* Current treatment options for arthrofibrosis primarily involve physiotherapy, operative manipulation, and surgical debridement, all with imperfect results.* Currently, there are no pharmacologic treatment options for arthrofibrosis. This has prompted increased investigational interest in the development of antifibrotic intra-articular therapies.

Measuring 3D In-vivo Shoulder Kinematics using Biplanar Videoradiography

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

Dynamic scapular recognition exercise improves scapular upward rotation and shoulder pain and disability in patients with adhesive capsulitis: a randomized controlled trial

BACKGROUND

Examine the ability of a dynamic scapular recognition exercise to improve scapular upward rotation and decrease shoulder pain and disability in patients with adhesive capsulitis of the shoulder.

METHODS

A test-retest randomized controlled study design was used. A total of sixty-six patients with unilateral adhesive capsulitis were equally divided into two groups. The study group received a dynamic scapular recognition exercise using a wireless biofeedback system, while the control group received placebo treatment in the form of active range-of-motion (ROM) exercises of the sound upper limb. A digital inclinometer was used to measure the scapular upward rotation and ROM of the shoulder joint, and the Shoulder Pain and Disability Index (SPADI) was used to measure the shoulder pain and disability.

RESULTS

Study results showed that after two weeks, there were statistically significant differences between the study and control groups in scapular upward rotation and shoulder flexion and abduction (P < .05) and nonsignificant differences in shoulder external rotation and SPADI (P > .05). After two and six months, there were statistically significant differences between study and control groups in scapular upward rotation; shoulder flexion, abduction and external rotation; and SPADI scores (P < .05).

CONCLUSION

This study showed that a dynamic scapular recognition exercise significantly improves scapular upward rotation and the ROM of shoulder flexion and abduction after two weeks. At two and six months, this exercise improves scapular upward rotation; ROM of shoulder flexion, abduction, and external rotation; and SPADI scores. These improvements persisted for six months after the performance of this exercise.

The Coupled Kinematics of Scapulothoracic Upward Rotation

BACKGROUND

Scapulothoracic upward rotation (UR) is an important shoulder complex motion allowing for a larger functional work space and improved glenohumeral muscle function. However, the kinematic mechanisms producing scapulothoracic UR remain unclear, limiting the understanding of normal and abnormal shoulder movements.

OBJECTIVE

The objective of this study was to identify the coupling relationships through which sternoclavicular and acromioclavicular joint motions contribute to scapulothoracic UR.

DESIGN

This was a cross-sectional observational study.

METHODS

Sixty participants were enrolled in this study; 30 had current shoulder pain, and 30 had no history of shoulder symptoms. Shoulder complex kinematics were quantified using single-plane fluoroscopy and 2D/3D shape matching and were described as finite helical displacements for 30-degree phases of humerothoracic elevation (30 degrees-60 degrees, 60 degrees-90 degrees, and 90 degrees-120 degrees). A coupling function was derived to estimate scapulothoracic UR from its component motions of acromioclavicular UR, sternoclavicular posterior rotation, and sternoclavicular elevation as a function of acromioclavicular internal rotation. The proportional contributions of each of the component motions were also calculated and compared between phases of humerothoracic elevation and groups.

RESULTS

Scapulothoracic UR displacement could be effectively predicted using the derived coupling function. During the 30- to 60-degree humerothoracic elevation phase, acromioclavicular UR accounted for 84.2% of scapulothoracic UR, whereas sternoclavicular posterior rotation and elevation each accounted for < 10%. During later phases, acromioclavicular UR and sternoclavicular posterior rotation each accounted for 32% to 42%, whereas sternoclavicular elevation accounted for < 11%.

LIMITATIONS

Error due to the tracking of sternoclavicular posterior rotation may have resulted in an underprediction of its proportional contribution and an overprediction of the proportional contribution of acromioclavicular UR.

CONCLUSIONS

Acromioclavicular UR and sternoclavicular posterior rotation are the predominant component motions of scapulothoracic UR. More research is needed to investigate how these coupling relationships are affected by muscle function and influenced by scapular dyskinesis.

Influence of Brassiere Wearing on Shoulder Kinematics

Objective

Gender differences in scapular kinematics during arm elevation have been reported. Because women wear brassieres (bras) daily, their scapular motion may be restricted by the garment; however, the influence of bra wearing on this motion has not been reported. Therefore, using a three-dimensional electromagnetic tracking device, we investigated the influence of bra wearing on shoulder kinematics during arm elevation.

Methods

The subjects were 19 healthy women, and the shoulder on the dominant side was evaluated. Subjects performed scapular plane arm elevation while wearing or not wearing bras. Kinematic data were recorded using an electromagnetic tracking device. The glenohumeral elevation angle, scapular upward and internal rotation angles, and the posterior tilt angle were determined from the recorded data. The angles were calculated at 20°-120° arm elevation, and the data were compared between the two conditions.

Results

The scapular upward and internal rotation angles and the posterior tilt angle were significantly smaller with the subjects wearing bras than not wearing bras. In contrast, the glenohumeral elevation angle was significantly greater when bras were warn.

Conclusions

Bra wearing may influence shoulder kinematics. Consequently, great care should be taken to account for this factor during the evaluation of kinematics in female subjects.

Kinematic analysis of the shoulder complex after anatomic and reverse total shoulder arthroplasty: A cross-sectional study

BACKGROUND

The movement of the arm relative to the trunk results from coordinated 3D glenohumeral and scapulothoracic movements. Changes in scapula kinematics may occur after total shoulder arthroplasty and could affect clinical and functional outcomes.

OBJECTIVES

To assess the 3D movement of the scapula during arm elevation after anatomic and reverse total shoulder arthroplasty.

DESIGN/METHODS

This was a single-centre, non-randomized, controlled cross-sectional study. Patients with anatomic (n = 14) and reverse total shoulder arthroplasty (n = 9) were prospectively enrolled and were compared to age-matched asymptomatic controls (n = 23). 3D scapular kinematics were assessed by a non-invasive, electromagnetic method during arm abduction and flexion. 3D scapular rotations and 3D linear displacements of the barycentre (geometrical centre) at rest and at 30°, 60° and 90° arm elevation; as well as scapulohumeral rhythm were analysed. Participant groups were compared using one-way ANOVA and Bonferroni post-hoc testing for normally distributed data, and Mann-Whitney U test for non-normally distributed data.

RESULTS/FINDINGS

Total range of scapular lateral rotation and barycentre displacement were increased, and scapulohumeral rhythm was reduced, in patients with anatomic and reverse total shoulder arthroplasty compared with age-matched controls; however, the global scapular kinematic pattern was preserved.

CONCLUSION/INTERPRETATION

For patients after total shoulder arthroplasty, the increased contribution of the scapula to arm elevation is consistent with a compensatory mechanism for the reduced glenohumeral mobility. The stability of the global scapula kinematic pattern reflects its mechanical and neuromotor strength.

Are Pulley Exercises Initiated 6 Weeks After Rotator Cuff Repair a Safe and Effective Rehabilitative Treatment? A Randomized Controlled Trial

BACKGROUND

There are few level 1 or 2 evidence studies that examine rehabilitation after rotator cuff repair. Pulleys have been used in postoperative shoulder rehabilitation with the intention of improving range of motion and developing strength. There is a concern that the use of pulleys in rehabilitation of rotator cuff repairs may contribute to excessive scapular motion (scapular substitution) and potentially inferior outcomes.

HYPOTHESIS

Rotator cuff repair patients treated with pulley exercises would have increased scapular substitution and inferior patient-determined outcome scores, range of motion, and strength compared with patients treated with an alternative rehabilitation program without pulleys.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 27 patients who underwent rotator cuff repair were randomized to a rehabilitation group that used pulleys initiated 6 weeks postoperatively, and 26 patients followed a rehabilitation protocol without pulleys. Inclusion criteria were patients undergoing arthroscopic rotator cuff repair. Exclusion criteria were large to massive rotator cuff tears, revision rotator cuff repair, glenohumeral osteoarthritis, adhesive capsulitis, and a symptomatic contralateral shoulder. Outcomes of intervention were patient-determined outcome scores (Western Ontario Rotator Cuff Index [WORC], American Shoulder and Elbow Surgeons [ASES] Shoulder Score, Single Assessment Numeric Evaluation [SANE], Shoulder Activity Level, and Simple Shoulder Test [SST]), range of motion, scapular substitution, and strength. Outcomes were determined at 6, 12, 18, 26, and 52 weeks. A power analysis determined that 22 patients were needed per group to have a power of 0.80, α = 0.05, and effect size of f = 0.5.

RESULTS

Both groups had statistically significant improvements in WORC, ASES Shoulder Score, SST, and SANE scores over time after rotator cuff repair (P < .0001). There were no differences between the interventions for WORC (P = .18), ASES Shoulder Score (P = .73), SANE (P = .5), Shoulder Activity Level (P = .39), or SST (P = .36). Both interventions demonstrated improvements in shoulder flexion (P = .002), abduction (P = .0001), external rotation (P = .02), strength (P ≤ .0002), and scapular substitution (P ≤ .07) over time after rotator cuff repair. However, there was no difference in range of motion (P ≥ .26), strength (P ≥ .20), or scapular substitution (P ≥ .17) between interventions.

CONCLUSION

A rotator cuff repair rehabilitation program that uses pulleys does not result in inferior outcomes, as determined by patient-determined outcome scores, measurements of scapular substitution, range of motion, and scaption strength.

REGISTRATION

ClinicalTrials.gov NCT01819909.

Shoulder Stiffness: Current Concepts and Concerns

Shoulder stiffness can be caused by various etiologies such as immobilization, trauma, or surgical interventions. The Upper Extremity Committee of ISAKOS defined the term "frozen shoulder" as idiopathic stiff shoulder, that is, without a known cause. Secondary stiff shoulder is a term that should be used to describe shoulder stiffness with a known cause. The pathophysiology of frozen shoulder is capsular fibrosis and inflammation with chondrogenesis, but the cause is still unknown. Conservative treatment is the primary choice. Pain control by oral medication, intra-articular injections with or without joint distension, and physical therapy are commonly used. In cases with refractory stiffness, manipulation under anesthesia or arthroscopic capsular release may be indicated. Because of various potential risks of complications with manipulations, arthroscopic capsular release is preferred. After the capsular release, stepwise rehabilitation is mandatory to achieve satisfactory outcome.

LEVEL OF EVIDENCE

Level V, evidence-based review.

Does Scapular Motion Regress with Aging and is It Restricted in Patients with Idiopathic Frozen Shoulder?

Purposes:

It has been reported that the amount of posterior tilt and upward rotation in scapular motions decreases with aging. The purposes of the current study were to investigate age related scapular motion regression and scapular restriction in patients with idiopathic frozen shoulder (IFS).

Methods:

The groups were recruited as follows: two groups of 50 asymptomatic subjects aged in their twenties and fifties, and 56 patients with IFS. We passively moved the scapula toward 8 directions: elevation/depression; upward/downward rotation; external/internal rotation; and anterior/posterior tilt. The grading of scapular motion was ranged from 0 to 3 (3, normal; and 0, severe restriction) and the score for each direction and the total aggregated score for all directions were calculated.

Results:

Scapular restriction was present in 3 subjects (6%) in the normal 20s group, 10 (14%) in the 50s group, and 51 (91%) in the IFS group. The total score between the normal 20s and 50s groups did not show statistical difference; however, greater significance was present between the normal 50s group and the IFS group (p < 0.01). There was statistical significance in depression (p < 0.01), downward rotation (p < 0.01), and posterior tilt (p < 0.01) among the 3 groups.

Conclusion:

Depression, downward rotation, and posterior tilt substantially regress with aging. Scapular motions towards depression, downward rotation, external rotation, and posterior tilt are severely restricted in the IFS group.

Dynamic Three-Dimensional Ultrasound to Evaluate Scapular Movement Among Manual Wheelchair Users and Healthy Controls

BACKGROUND

A large percentage of individuals with spinal cord injury (SCI) report shoulder pain that can limit independence and quality of life. The pain is likely related to the demands placed on the shoulder by transfers and propulsion. Shoulder pathology has been linked to altered scapular mechanics; however, current methods to evaluate scapular movement are invasive, require ionizing radiation, are subject to skin-based motion artifacts, or require static postures.

OBJECTIVE

To investigate the feasibility of applying 3-dimensional ultrasound methods, previously used to look at scapular position in static postures, to evaluate dynamic scapular movement.

METHODS

This study evaluated the feasibility of the novel application of a method combining 2-dimensional ultrasound and a motion capture system to determine 3-dimensional scapular position during dynamic arm elevation in the scapular plane with and without loading.

RESULTS

Incremental increases in scapular rotations were noted for extracted angles of 30°, 45°, 60°, and 75° of humeral elevation. Group differences were evaluated between a group of 16 manual wheelchair users (MWUs) and a group of age- and gender-matched able-bodied controls. MWUs had greater scapular external rotation and baseline pathology on clinical exam. MWUs also had greater anterior tilting, with this difference further accentuated during loading. The relationship between demographics and scapular positioning was also investigated, revealing that increased age, pathology on clinical exam, years since injury, and body mass index were correlated with scapular rotations associated with impingement (internal rotation, downward rotation, and anterior tilting).

CONCLUSIONS

Individuals with SCI, as well as other populations who are susceptible to shoulder pathology, may benefit from the application of this imaging modality to quantitatively evaluate scapular positioning and effectively target therapeutic interventions.

Collecting shoulder kinematics with electromagnetic tracking systems and digital inclinometers: A review

The shoulder complex presents unique challenges for measuring motion as the scapula, unlike any other bony segment in the body, glides and rotates underneath layers of soft tissue and skin. The ability for clinicians and researchers to collect meaningful kinematic data is dependent on the reliability and validity of the instrumentation utilized. The aim of this study was to review the relevant literature pertaining to the reliability and validity of electromagnetic tracking systems (ETS) and digital inclinometers for assessing shoulder complex motion. Advances in technology have led to the development of biomechanical instrumentation, like ETS, that allow for the collection of three-dimensional kinematic data. The existing evidence has demonstrated that ETS are reliable and valid instruments for collecting static and dynamic kinematic data of the shoulder complex. Similarly, digital inclinometers have become increasingly popular among clinicians due to their cost effectiveness and practical use in the clinical setting. The existing evidence supports the use of digital inclinometers for the collection of shoulder complex kinematics as these instruments have been demonstrated to yield acceptable reliability and validity. While digital inclinometers pose a disadvantage to ETS regarding accuracy, precision, and are limited to two-dimensional and static measurements, this instrument provides clinically meaningful data that allow clinicians and researchers the ability to measure, monitor, and compare shoulder complex kinematics.

The comparison of scapular upward rotation and scapulohumeral rhythm between dominant and non-dominant shoulder in male overhead athletes and non-athletes

Previous studies have stated that the scapulohumeral rhythm dysfunction can make person prone to glenohumeral joint pathologies. The purpose of this study was to compare scapular upward rotation and scapulohumeral rhythm between dominant and non-dominant shoulder in male overhead athletes and non-athletes. Seventeen overhead athletes and seventeen non-athletes volunteered for this study. Two inclinometers were used to measure humeral abduction and scapular upward rotation in rest position, 45°, 90° and 135° humeral abduction in frontal plane. Findings indicated there was no significant asymmetry in scapular upward rotation and scapulohumeral rhythm in different abduction angles between dominant and non-dominant shoulder in non-athletes. In contrast, overhead athletes' dominant shoulders have more downward rotation in scapular rest position and more upward rotation in 90° and 135° shoulder abduction than non-dominant shoulders. Also, overhead athletes presented scapulohumeral rhythm asymmetry between dominant and non-dominant shoulder in 90° and 135° humeral abduction as dominant shoulders have less scapulohumeral rhythm ratio than non-dominant shoulders. Furthermore, overhead athletes dominant shoulders have more scapular downward rotation in scapular rest position, more scapular upward rotation in 90° and 135° humeral abduction and less scapulohumeral rhythm ratio in 45°, 90° and 135° humeral abduction than non-athletes in dominant shoulders. We suggest that clinicians should be aware that some scapular asymmetry may be common in some athletes. It should not be considered as a pathological sign but rather an adaptation to extensive use of upper limb.

Shoulder limited joint mobility in people with diabetes mellitus

BACKGROUND

Limited joint mobility at the shoulder is an understudied problem in people with diabetes mellitus. The purpose of this study was to determine the differences in shoulder kinematics between a group with diabetes and those without diabetes.

METHODS

Fifty-two participants were recruited, 26 with diabetes and 26 non-diabetes controls (matched for age, BMI and sex). Three-dimensional position of the trunk, scapula and humerus were collected using electromagnetic tracking sensors during scapular plane elevation and rotation movements.

FINDINGS

Glenohumeral external rotation was reduced by 11.1°-16.3° (P<0.05) throughout the humerothoracic elevation range of motion, from neutral to peak elevation, in individuals with diabetes as compared to controls. Peak humerothoracic elevation was decreased by 10-14°, and peak external rotation with the arm abducted was decreased 22° in the diabetes group compared to controls (P<0.05). Scapulothoracic and glenohumeral internal rotation motions were not different between the two groups.

INTERPRETATION

Shoulder limited joint mobility, in particular decreased external rotation, was seen in individuals with diabetes as compared to control participants. Future research should investigate causes of diabetic limited joint mobility and strategies to improve shoulder mobility and prevent additional detrimental changes in movement and function.

Distal radius fractures result in alterations in scapular kinematics: a three-dimensional motion analysis

BACKGROUND

Scapular motion is closely integrated with arm motion. Injury to a distal segment requires compensatory changes in the proximal segments leading to alterations in scapular motion. Since the effects of distal injuries on scapular kinematics remain unknown, in the present study we investigated the influences on scapular motion in patients with distal injuries.

METHODS

Sixteen subjects with a history of distal radius fracture and 20 asymptomatic healthy subjects (controls) participated in the study. Three-dimensional scapular and humeral kinematic data were collected on all 3 planes of shoulder elevation: frontal, sagittal, and scapular. All testing was performed in a single session; therefore, the sensors remained attached to the participants for all testing. The position and orientation data of the scapula at 30°, 60°, 90°, and 120° humerothoracic elevation and 120°, 90°, 60°, and 30° lowering were used for statistical comparisons. Independent samples t-test was used to compare the scapular internal/external rotation, upward/downward rotation, and anterior/posterior tilt between the affected side of subjects with a distal radius fracture and the dominant side of asymptomatic subjects at the same stage of humerothoracic elevation.

FINDINGS

Scapular internal rotation was significantly increased at 30° elevation (P=0.01), 90° elevation (P=0.03), and 30° lowering (P=0.03), and upward rotation was increased at 30° and 60° elevation (P<0.001) on the affected side during frontal plane elevation. Scapular upward rotation and anterior tilt were significantly increased during 30° lowering on both the scapular (P=0.002 and 0.02, respectively) and sagittal planes (P=0.01 and 0.02. respectively).

INTERPRETATION

Patients with distal radius fractures exhibit altered scapular kinematics, which may further contribute to the development of secondary musculoskeletal pathologies.

A new description of scapulothoracic motion during arm movements in healthy subjects

The participation of scapula motion in arm movement is clinically well known and recent three dimensional (3D) analyses using kinematic techniques have confirmed its importance. Scapular motion relative to the thorax has a theoretical maximum of 6 degrees of freedom (DoF), resulting from rotations at both clavicular joints (3 rotational DoF each). However, most recent kinematic studies have only analysed the 3D rotations of the scapula relative to the thorax. In the present study, the 3D translations of the barycentre of the scapula were considered in order to complete the description of movement at the shoulder complex. Eight healthy subjects performed arm elevation in the sagittal and frontal planes, simulated activities of daily living (hair combing and back washing) and maximum voluntary scapula movement (forward and backward rolling). Measurements were recorded using a 6 DoF electromagnetic device and the acromial method of analysis was used. The results showed that 3D scapular rotations and translation of its barycentre were functionally consistent for all tasks. A principal component analysis (PCA) yielded three factors, explaining 97.6% of the variance. The first two factors (protraction and shrug, according to clinical descriptions) combined rotations and translations, consistent with the hypothesis that the scapula rolls over the curved thoracic surface. The third factor related to lateral-medial rotation, thus representing rotation in the plane tangential to the thorax. The PCA suggested that scapular motion can be described using these 3 DoF. This should be studied in a larger group of individuals, including patients with pathological conditions.

MEASURING SCAPULAR MOVEMENT USING THREE-DIMENSIONAL ACROMIAL PROJECTION

Background

The current jig standard for measuring scapulohumeral movement of the shoulder complex only allows for static measurements of scapular positioning.

Methods

We compared scapular positioning as determined by a scapular jig with that projected from a marker triad placed on the acromion process of the scapula using an infrared motion capture system. Nine individuals performed abduction and scaption shoulder movements while arm and shoulder positioning were recorded during static and dynamic trials. Virtual scapulae were projected from surface marker triads on participants' acromia and compared with the position of three scapular landmarks identified by placement of a customized plastic jig. Static and dynamic positioning at a series of angles was compared to the jig standard to determine validity of the technique.

Results

There were no statistically significant differences between the virtual projections and jig standard for scapular external rotation, upward rotation, and anterior-posterior tilt planar measurements. Dynamic positioning correlated well with static projections, but virtual scapular projections generally overestimated upward rotation of the scapulae, as compared to the jig. This could potentially be corrected through the development of a linear correction factor.

Conclusion

Acromial projection allows for reproducible, non-invasive dynamic video motion capture of the scapula.

Effects of a scapula-oriented shoulder exercise programme on upper limb dysfunction in breast cancer survivors: a randomized controlled pilot trial

OBJECTIVE

To examine the effects of a scapula-oriented exercise on upper limb dysfunction in breast cancer survivors.

STUDY DESIGN

A prospective randomized, controlled pilot trial with historical control.

SETTING

Rehabilitation department at a university hospital.

SUBJECTS

Thirty-two women with breast cancer were randomly assigned to scapula-oriented exercise group (n = 16) and general exercise group (n = 16). An historical control group (n = 18) without exercise was enrolled from breast cancer survivors.

INTERVENTIONS

The scapula-oriented exercises were designed focusing on scapulothoracic movement. The general exercise group performed body conditioning exercise. Exercise therapies were performed for one session per week for eight weeks.

MAIN OUTCOME MEASURES

Pain and physical disabilities related to upper limb dysfunction, quality of life and depression were used as subjective outcomes. Objective outcome measures included shoulder range of motion and strength. Outcomes were assessed at baseline and post exercise.

RESULTS

At baseline, no significant difference was observed among the three groups. The scapula-oriented exercise group showed improvements in pain, physical function, social function, and global quality of life compared with baseline, whereas the general exercise group showed improved fatigue and range of motion. The change in global quality of life (P = 0.067; effect size, 0.33) and strength of external rotation (P = 0.001; effect size, 0.55) were significantly greater in the scapula-oriented exercise group than in the general exercise and control group.

CONCLUSION

Scapula-oriented exercise had beneficial effects on pain, quality of life and aspects of strength. The sample size required in a larger definitive study is 32 subjects per group.

Effects of mastectomy on shoulder and spinal kinematics during bilateral upper-limb movement

BACKGROUND

Shoulder movement impairment is a commonly reported consequence of surgery for breast cancer.

OBJECTIVE

The aim of this study was to determine whether shoulder girdle kinematics, including those of the scapula, spine, and upper limb, in women who have undergone a unilateral mastectomy for breast cancer are different from those demonstrated by an age-matched control group.

DESIGN

An observational study using 3-dimensional kinematic analysis was performed.

METHODS

Women who had a unilateral mastectomy on their dominant-arm side (n=29, mean [+/-SD] age=62.4+/-8.9 years) or nondominant-arm side (n=24, mean [+/-SD] age=59.8+/-9.9 years), as well as a control group of age-matched women without upper-limb, shoulder, or spinal problems (n=22, mean [+/-SD] age=58.1+/-11.5 years), were measured while performing bilateral arm movements in the sagittal, scapular, and coronal planes. All of the women were free of shoulder pain at the time of testing. Data were collected from the glenohumeral joint, the scapulothoracic articulation, and the spine (upper and lower thoracic and lumbar regions) using an electromagnetic tracking system.

RESULTS

Women following mastectomy displayed altered patterns of scapular rotation compared with controls in all planes of movement. In particular, the scapula on the mastectomy side rotated upward to a markedly greater extent than that on the nonmastectomy side, and women following mastectomy displayed greater scapular excursion than controls.

CONCLUSIONS

The findings suggest that altered motor patterns of the scapula are associated with mastectomy on the same side. Whether these changes are harmful or not is unclear. Investigation of interventions designed to restore normal scapulohumeral relationships on the affected side following unilateral mastectomy for breast cancer is warranted.

Different scapular kinematics in healthy subjects during arm elevation and lowering: glenohumeral and scapulothoracic patterns

HYPOTHESIS

The scapulothoracic (ST) joint affects glenohumeral (GH) joint function. We observed 3-dimensional scapular motions during arm elevation and lowering to identify the scapulohumeral rhythm in healthy subjects and to compare it between the dominant and nondominant arms.

MATERIALS AND METHODS

Twenty-one healthy subjects participated in this study. Participants randomly elevated and lowered the arms in the scapular plane, and data were recorded by a computerized 3-dimensional motion analyzer at each 10 degrees increment.

RESULTS

Of the 42 shoulders, 21 showed a greater ratio of GH motion relative to ST motion whereas the other 21 showed a smaller ratio of GH motion relative to ST motion. The angle of upward rotation of the scapula showed a statistically significant difference between both types. The mean maximum angles of upward rotation, posterior tilting, and internal rotation were 36.2 degrees +/- 7.0 degrees , 38.7 degrees +/- 5.7 degrees , and 36.8 degrees +/- 12.2 degrees , respectively. No significant difference was found in angles of 3 scapular rotations between the dominant and nondominant arms.

DISCUSSION

These results indicate that there are 2 distinctly different scapulohumeral rhythms in healthy subjects but without a significant difference between dominant and nondominant arms. These findings should be referred to when one is interpreting kinematics in a variety of shoulder disorders.

Scapular kinematics in constrained and functional upper extremity movements

STUDY DESIGN

Controlled laboratory study using a single-group, repeated-measures design.

OBJECTIVES

To investigate scapular kinematics during both constrained and functional shoulder movements.

BACKGROUND

Abnormal scapulothoracic joint motion has been associated with pathologies such as shoulder impingement. Constrained protocols are commonly used in the measurement of shoulder kinematics; however, few studies have measured motion during functional tasks.

METHODS

Twenty-five healthy subjects participated in this study. Three-dimensional kinematic data from the scapula and humerus with respect to the thorax were collected with a magnetic tracking system. Functional testing consisted of 6 different tasks representing common activities of daily living. Constrained testing consisted of at least 42 arm elevations in various planes. Two-way analyses of variance with repeated measures were used to compare scapular rotations between constrained and functional movements at the same humeral elevation and plane of elevation angles. Intersubject variability was compared between the overhead tasks and the constrained humeral elevation in the scapular plane by using the coefficient of multiple correlations.

RESULTS

Significant differences between constrained trials and functional tasks were found for all scapular rotations. A similar pattern was observed for scapular rotations variability between overhead tasks and constrained arm elevation in the scapular plane.

CONCLUSION

Care needs to be taken when comparing and generalizing scapular kinematic data from constrained humeral movements and applying it to functional humeral movements.

Rotator cuff tear pain and tear size and scapulohumeral rhythm

CONTEXT

The body of knowledge concerning shoulder kinematics in patients with rotator cuff tears is increasing. However, the level of understanding regarding how pain and tear size affect these kinematic patterns is minimal.

OBJECTIVE

To identify relationships between pain associated with a full-thickness rotator cuff tear, tear size, and scapulohumeral rhythm (SHR) and to determine whether pain and tear size serve as predictors of SHR.

DESIGN

A test-retest design was used to quantify pain and SHR before and after a subacromial lidocaine injection. Correlation and multivariate analyses were used to identify relationships among pain, tear size, and SHR.

SETTING

Orthopaedic biomechanics research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Fifteen patients (age range, 40-75 years) with diagnosed full-thickness rotator cuff tears participated. They were experiencing pain at the time of testing.

INTERVENTION(S)

Shoulder kinematic data were collected with an electromagnetic tracking system before and after the patient received a lidocaine injection.

MAIN OUTCOME MEASURE(S)

Pain was rated using a visual analog scale. Three-dimensional scapular kinematics and glenohumeral elevation were assessed. Scapular kinematics included anterior-posterior tilt, medial-lateral tilt, and upward-downward rotation. A regression model was used to calculate SHR (scapular kinematics to glenohumeral elevation) for phases of humeral elevation and lowering.

RESULTS

Linear relationships were identified between initial pain scores and SHR and between tear size and SHR, representing an increased reliance on scapular motion with increasing pain and tear size. Pain was identified as an independent predictor of SHR, whereas significant findings for the effect of tear size on SHR and the interaction between pain and tear size were limited.

CONCLUSIONS

We noted an increased reliance on scapular contributions to overall humeral elevation with increasing levels of pain and rotator cuff tear size. Pain associated with a rotator cuff tear serves as a primary contributor to the kinematic patterns exhibited in patients with rotator cuff tears.

Analysis of the scapulohumeral rhythm and electromyography of the shoulder muscles during elevation and lowering: comparison of dominant and nondominant shoulders

HYPOTHESIS

Assessment of whether elevation and lowering of the dominant and nondominant arms occur in a similar manner in healthy individuals is clinically important in terms of shoulder disorders.

MATERIALS AND METHODS

We examined the scapulohumeral rhythm (SHR) and performed electromyography (EMG) for the middle deltoid, upper trapezius, lower trapezius, and lower part of the serratus anterior muscles of both shoulders in 18 healthy volunteers (14 men, 4 women) with a mean age of 24 years (range, 19-30 years). The participants randomly elevated and lowered either the right or left arm in the scapular plane, and the motion was measured using a 3-dimensional motion analyzer.

RESULTS

The average angles of maximum arm elevation and scapular upward rotation were 130.3 degrees +/- 7.9 degrees and 32.2 degrees +/- 5.6 degrees, respectively, for dominant arms, and 130.8 degrees +/- 6.4 degrees and 31.8 degrees +/- 5.8 degrees, respectively, for nondominant arms. The SHR in each 10 degrees increment did not differ significantly between the dominant and nondominant arms in each participant during elevation (P = .337) and lowering (P = .1). A significant difference was found in the percentage integrated EMG (%IEMG) of the lower trapezius between the 2 shoulders (P < .049).

DISCUSSION

If the kinematic difference is identified between both shoulders, we can predict the dysfunction or disorder in shoulder complex. Moreover, we should evaluate how shoulder muscles are used and whether the muscle becomes weak.

CONCLUSIONS

Healthy individuals elevate and lower the dominant and nondominant shoulders in a similar kinematical pattern despite 3 of 4 muscles indicating different EMG activities between both shoulders.

Lengthening of the pectoralis minor muscle during passive shoulder motions and stretching techniques: a cadaveric biomechanical study

BACKGROUND AND PURPOSE

Lengthening of the pectoralis minor muscle (PMi) during passive shoulder motions and the effect of stretching techniques for this muscle are unclear. The purposes of this study were: (1) to investigate the amount and pattern of the lengthening between passive shoulder motions and (2) to determine which stretching technique effected the greatest change in PMi length.

METHODS

Nine fresh cadaveric transthoracic specimens were used. Lengthening in the lateral and medial fiber group of the PMi was directly measured during 3 passive shoulder motions (flexion, scaption, and external rotation at 90 degrees of abduction) and 3 stretching techniques (scapular retraction at 0 degrees and 30 degrees of flexion and horizontal abduction) for this muscle. The measurement was conducted by using a precise displacement sensor.

RESULTS

Although the length of the PMi linearly increased during all shoulder motions, lengthening during flexion and scaption was steeper and significantly larger than that during external rotation at 90 degrees of abduction. For the stretching techniques, scapular retraction at 30 degrees of flexion and horizontal abduction stretched the PMi more than scapular retraction at 0 degrees of flexion. In comparison with lengthening at 150 degrees of flexion, scapular retraction at 30 degrees of flexion significantly stretched the medial fiber group of the muscle.

DISCUSSION AND CONCLUSION

The extensive lengthening of the PMi is necessary during shoulder motions, especially flexion and scaption. Scapular retraction at 30 degrees of flexion makes the greatest change in PMi length. This study suggests the importance of the PMi in shoulder motion and provides anatomical and biomechanical evidence that might guide appropriate selection of stretching techniques.

The association of scapular kinematics and glenohumeral joint pathologies

There is a growing body of literature associating abnormal scapular positions and motions, and, to a lesser degree, clavicular kinematics with a variety of shoulder pathologies. The purpose of this manuscript is to (1) review the normal kinematics of the scapula and clavicle during arm elevation, (2) review the evidence for abnormal scapular and clavicular kinematics in glenohumeral joint pathologies, (3) review potential biomechanical implications and mechanisms of these kinematic alterations, and (4) relate these biomechanical factors to considerations in the patient management process for these disorders. There is evidence of scapular kinematic alterations associated with shoulder impingement, rotator cuff tendinopathy, rotator cuff tears, glenohumeral instability, adhesive capsulitis, and stiff shoulders. There is also evidence for altered muscle activation in these patient populations, particularly, reduced serratus anterior and increased upper trapezius activation. Scapular kinematic alterations similar to those found in patient populations have been identified in subjects with a short rest length of the pectoralis minor, tight soft-tissue structures in the posterior shoulder region, excessive thoracic kyphosis, or with flexed thoracic postures. This suggests that attention to these factors is warranted in the clinical evaluation and treatment of these patients. The available evidence in clinical trials supports the use of therapeutic exercise in rehabilitating these patients, while further gains in effectiveness should continue to be pursued.

LEVEL OF EVIDENCE

Level 5.

Utility of the frontal plane projection angle in females with patellofemoral pain

STUDY DESIGN

Case-control study of females with patellofemoral pain syndrome (PFPS) and a control group.

OBJECTIVES

Three different approaches were used to examine the utility of a 2-dimensional (2-D) frontal plane projection angle (FPPA) measure of knee alignment. First, we measured the FPPA association with respect to 3-dimensional (3-D) lower extremity joint rotations during single-leg squats. Second, we determined the correlation of the FPPA during single-leg squats with hip and knee joint rotations during running and single leg jumping. Third, we compared the FPPA between females with and without PFPS.

BACKGROUND

PFPS is associated with altered lower extremity kinematics during weight-bearing activities that decrease retropatellar contact area and increase retropatellar stress. An objective and simple procedure to quantify altered kinematics during weight-bearing activities may help clinicians identify individuals who may likely benefit from interventions to improve lower extremity kinematics.

METHODS AND MEASURES

Twenty females with PFPS and 20 healthy female controls performed single-leg squats, running, and repetitive single-leg jumps while 3-D lower extremity kinematics were recorded. The FPPA was recorded by a digital camera during single-leg stance and single-leg squats. Correlation coefficients were used to quantify the association between the FPPA and transverse and frontal plane hip and knee angles for all activities. Independent t tests were used to compare FPPA values between groups.

RESULTS

FPPA values representing medial displacement of the knee during single-leg squats were associated with increased hip adduction (r = 0.32 to 0.38, P<.044) and knee external rotation (r = 0.48 to 0.55, P<.001) across activities. FPPA values for the PFPS group reveal greater medial displacement of the knee compared with those of the control group during single-leg squats (P = .012).

CONCLUSION

The association between the FPPA and lower extremity kinematics that are associated with PFPS suggest that the FPPA during single-leg squats may be a useful clinical measure. However, these methods should not be used to quantify 3-D joint rotations.