Scapular Orientation Research Articles

Impact of scapula anatomical landmark positioning on scapular orientation using CT-based 3D models: an intra-observer repeatability and inter-observer reproducibility study

HypothesisThe primary objective of this study was to assess intra-observer repeatability and inter-observer reproducibility of the 3D coordinates of a set of scapula anatomical landmarks obtained by manual positioning on conventional supine CT-scan based scapula surface models. The secondary objective was to assess intra-observer repeatability and inter-observer reproducibility of the resulting 3D scapular orientation. It was hypothesized that the 3D scapular orientation reliability would be better or similar than established reliability of intra-operative baseplate positioning (i.e. version and inclination) in reverse total shoulder arthroplasty (rTSA). MethodsThree anatomical landmarks, i.e. acromial angle (AA), inferior angle (IA), and trigonum scapulae (TS), were manually positioned on 81 scapula surface models using updated landmark definitions. These models were obtained by the segmentation of CT-scan images acquired from patients undergoing elective rTSA procedures at the Department of Surgery at Geneva University Hospitals between May 2022 and December 2023. This procedure was repeated 3 times per scapula by 3 independent observers. A set of parameters corresponding to the 3D landmark coordinates (expressed in an average scapula coordinate system) and the 3D scapular orientation (expressed as three angles related to the retraction/protraction, lateral/medial rotation, and internal/external rotation) were computed. Intra-observer repeatability and inter-observer reproducibility were assessed for each of these parameters using an intra-class correlation as a relative reliability metric. Standard error of measurement (SEM) was also reported as an absolute reliability metric. ResultsIntra-observer ICC and inter-observer ICC ranged from poor to moderate for AA, poor to excellent for IA, and poor to excellent for TS. However, low SEM, ranging from 0.4 mm to 2.4 mm for intra-observer repeatability and from 0.2 mm to 1.8 mm for inter-observer reproducibility, were obtained for every coordinate of each anatomical landmark. This results in poor to moderate intra-observer ICC and inter-observer ICC for scapula angular orientation. Again, low SEM, ranging from 0.4° to 0.8° for intra-observer repeatability and 0.4° to 0.6° for inter-observer reproducibility, were obtained, arguing for reliable measurements. Discussion and ConclusionThis study demonstrates that manual positioning of the three scapula anatomical landmarks recommended by the International Society of Biomechanics can be performed in a reliable manner across measures and observers on surface bone models obtained from CT-scan images. However, a clear and standardized definition of these landmarks is needed to ensure consistency across measurements.

The influence of scapular orientation on the medial scapula corpus angle in snapping scapula syndrome

The influence of scapular orientation on the medial scapula corpus angle in snapping scapula syndrome

Three-dimensional scapular orientation: a comparison of glenohumeral osteoarthritis and cuff tear arthropathy to the unaffected shoulder

BackgroundScapular orientation may play an important role in preoperative planning for shoulder arthroplasty; however, there is currently no defined method for producing standardized three-dimensional measurements. The purpose of this study is to develop a reproducible measurement system of scapular orientation and to evaluate differences between unaffected shoulders and those with diagnoses of primary glenohumeral osteoarthritis (GHOA) and rotator cuff tear arthropathy (CTA). MethodsPatients receiving computed tomography scans for preoperative shoulder arthroplasty planning were enrolled prospectively. Thin sliced axial images that included bilateral shoulders and the thorax were reformatted. The pathology of the bilateral glenohumeral joints was defined as GHOA, CTA, or unaffected. Scapular orientation was defined relative to the thorax using three-dimensional models to define the protraction, rotation, and tilt angles in the supine position. Univariate analysis was performed to compare demographics and scapular measurements between patients with GHOA, CTA, and unaffected shoulder pathology. Multivariate linear regression analysis was performed to identify independent predictors of scapular orientation. ResultsOne hundred fifty-eight shoulders, comprising 79 patients were included. Twenty-seven percent (n = 21/79) of patients had an unaffected contralateral shoulder. Shoulders with GHOA had significantly greater downward scapular rotation (-14 ± 7 degrees) than both unaffected shoulders (-8 ± 7 degrees; P < .001) and those with CTA (-7 ± 8 degrees; P < .001). Increased downward scapular rotation was predicted by a shoulder pathology of GHOA in multivariate analysis (beta -7.09; P < .001). The magnitude of side-to-side difference was greatest in scapular rotation for patients with GHOA compared to CTA, with no significant differences in tilt or protraction. ConclusionScapular rotation in the supine position varies by shoulder pathology, with greater downward rotation seen in patients with primary GHOA. These findings underscore the need for awareness of scapular orientation in addition to glenoid morphology when evaluating and planning shoulder arthroplasty cases.

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

One proposed mechanism of rotator cuff disease is scapular motion impairments contributing to rotator cuff compression and subsequent degeneration. To model the effects of scapular angular deviations on rotator cuff tendon proximity for subacromial and internal mechanical impingement risk during scapular plane abduction. Descriptive laboratory study. Three-dimensional bone models were reconstructed from computed tomography scans obtained from 10 asymptomatic subjects and 9 symptomatic subjects with a clinical presentation of impingement syndrome. Models were rotated to average scapular orientations from a healthy dataset at higher (120°) and lower (subject-specific) humeral elevation angles to investigate internal and subacromial impingement risks, respectively. Incremental deviations in scapular upward/downward rotation, internal/external rotation, and anterior/posterior tilt were imposed on the models to simulate scapular movement impairments. The minimum distance between the rotator cuff insertions and potential impinging structures (eg, glenoid, acromion) was calculated. Two-way mixed-model analyses of variance assessed for effects of scapular deviation and group. At 120° of humerothoracic elevation, minimum distances from the supraspinatus and infraspinatus insertions to the glenoid increased with ≥5° changes in upward rotation (1.6-9.8 mm, P < .001) or external rotation (0.9-5.0 mm, P≤ .048), or with ≥10° changes in anterior tilt (1.1-3.2 mm, P < .001). At lower angles, ≥20° changes in most scapular orientations significantly increased the distance between the supraspinatus and infraspinatus insertions and the acromion or coracoacromial ligament. A reduction in scapular upward rotation decreases the distance between the rotator cuff tendon insertions and glenoid at 120° humerothoracic elevation. Interpretation is complicated for lower angles because the humeral elevation angle was defined by the minimum distance. These results may assist clinical decision making regarding the effects of scapular movement deviations in patients with rotator cuff pathology and scapular dyskinesia and may help inform the selection of clinical interventions.

The V angle compliments radiographic assessment of acute acromioclavicular joint dislocations by differentiating between Rockwood types III versus V and by considering dynamic horizontal translation in coronal radiographs.

Acromioclavicular joint (ACJ) dislocations are usually graded radiographically according to Rockwood, but differentiation between Rockwood types III and V may be ambiguous. The potentially clinically relevant horizontal instability is barely addressed in coronal radiographs. It was hypothesized that a new radiologic parameter (V angle) would complement ACJ diagnostics on anteroposterior radiographs by differentiating between cases of Rockwood III and V while also considering the aspect of dynamic horizontal translation (DHT). Ninety-five patients with acute ACJ dislocations (Rockwood types III and V) were included retrospectively between 2017 and 2020. On anteroposterior views (weightbearing: n = 62, non-weight-bearing: n = 33), the coracoclavicular (CC) distance and the newly introduced V angle for assessing scapular orientation were measured bilaterally. This angle is referenced between the spinal column and a line crossing the superior scapular angle and the crossing point between the supraspinatus fossa and the medial base of the coracoid process, reported as the side-comparative difference (non-injured side *minus* injured side). DHT on Alexander views was divided into stable, partially unstable or completely unstable. The V angle on the injured side alone (mean 50.0°; 95% confidence interval (CI), 48.6°-51.3°) showed no correlation with the side-comparative CC distance [%] (r = - 0.040; n.s.). Thus, the V angle on the non-injured side was considered, displaying a normal distribution (n.s.) with a mean of 58.0° (95% CI, 56.6°-59.4°). The side-comparative V angle showed a correlation with the side-comparative CC distance (r = 0.83; p < 0.001) and was able to differentiate between Rockwood types III (4.7°; 95% CI, 3.9°-5.5°; n = 39) and V (10.3°; 95% CI, 9.7°-11.0°; n = 56) (p < 0.001). A cut-off value of 7° had a 94.6% sensitivity and an 82.1% specificity (area under curve, AUC: 0.954; 95% CI, 0.915-0.994). The side-comparative V angle was greater for cases with complete DHT (8.7°; 95% CI, 7.9°-9.5°; n = 78) than for cases with partial DHT (4.8°; 95% CI, 3.3°-6.3°; n = 16) (p < 0.001). A cut-off value of 5° showed a sensitivity of 84.6% and a specificity of 66.7% (AUC 0.824; 95% CI, 0.725-0.924). The scapular-based V angle on anteroposterior radiographs distinguishes between Rockwood types III and V as well as cases with partial or complete DHT. Diagnostic study. Level II.

Influence of marker weights optimization on scapular kinematics estimated with a multibody kinematic optimization

Scapular kinematic estimates are altered by soft tissue artefacts, therefore experimental and numerical methods should be developed to improve their accuracy. This study aimed to assess the influence of weights applied to the scapula markers within a closed-loop multibody kinematic optimization on scapular kinematic estimates. Fifteen healthy volunteers performed static postures mimicking analytical, daily living and sport movements. Scapulo-thoracic angles were computed either from a scapula locator as the reference, or from a closed-loop multibody-kinematic optimization (MKO) including a participant-specific point-on-ellipsoid scapulothoracic joint. Weights applied to scapula markers in the MKO were optimized to minimize the difference in scapular orientation from the reference. Optimizing weighting sets significantly (p < 0.0001) improved scapular orientation from 0.9° to 12.1° in comparison to scapular kinematics estimated with non-optimized weighting sets. The mean optimized weighting set contained no neglectable weight for all markers from the acromion to the medial border of the scapular spine but showed no significant difference (p = 0.547) compared to homogeneous weights. Optimized weighting sets were participant- and movement- specific. To conclude, homogenous weights applied on redundant markers located from acromion to scapular medial border spine are recommended when estimating scapular kinematics in upper limb MKO.

Muscle fatigue response of rotator cuff muscles in different postures

IntroductionMuscle fatigue is a leading cause of rotator cuff (RC) pathologies. Scapular orientation affected by changes in the thoracic spine account for differences in body postures leading to altered RC muscle activation. This posture-related alteration in RC muscle activation and its fatigue response needs to be analyzed.Materials and methodsThis study included 50 healthy shoulders with no coexisting spine pathologies. Raw data were recorded using electromyography sensors for RC muscles during two isometric maneuvers of abduction and external rotation, performed at 30% maximum voluntary contraction at 30°, 45°, and 90° arm elevation in sitting and standing. The raw data were analyzed in DataLITE® software, and the mean power frequency (MPF) was extracted to analyze the fatigue response of RC muscles. The Wilcoxon signed-rank test and Kruskal–Wallis test with Bonferroni corrections analyzed fatigue differences between postures and various activities. P < 0.05 was considered significant for the results.ResultsSupraspinatus muscle demonstrated significant fatigue at 90° of arm elevation in standing as compared to sitting (MPF −5.40: −5.41; P = 0.03) posture. Between the three elevation angles, all the RC muscles showed increased fatigue at 90° (MPF range −5.22 to −6.64). When compared between abduction and external rotation, only infraspinatus showed fatigue in external rotation (MPF range −5.42 to −6.08). Among all the three RC muscles, infraspinatus showed the maximum fatigue of MPF −6.64 when compared to supraspinatus −5.22 and teres minor −5.36.ConclusionThe findings indicate that alterations in the body postures and different elevation angles affect the RC muscles’ fatigue response.

Evaluation of approaches to estimate scapular kinematics during baseball pitching

ABSTRACT Biomechanical analyses of pitching possess limitations in accurately measuring dynamic scapular orientation and are thus unable to distinguish between glenohumeral and scapulothoracic contributions to global shoulder motion. In lieu of direct measurement, several methods to estimate scapular kinematics have been developed. This study evaluated the ability of the linear model and the double calibration acromion marker cluster (D-AMC) approaches to estimate scapular kinematics throughout a full-speed pitching motion. Each approach’s estimates were compared against scapulothoracic range of motion limits established in a non-pitching biplane fluoroscopy study involving various functional arm movements that approximate physiological limits of scapular motion. Fourteen healthy collegiate pitchers participated. Motion capture measured upper extremity joint kinematics during full-speed fastball pitches. Linear model and D-AMC approaches estimated scapulothoracic kinematics during each pitch. Linear model estimates of scapulothoracic kinematics were largely within established physiological limits on each scapular axis of motion while D-AMC estimates exceeded fluoroscopy-established bounds for more subjects and by larger, less physiologically plausible amounts. These findings demonstrate that the linear model outperforms the D-AMC and suggest that it is a viable approach to estimate scapular kinematics during pitching. Finally, these results offer additional evidence to support the accepted pattern of scapular kinematics during pitching.

Assessment of approaches to estimate scapular orientation in children with brachial plexus birth injury

BackgroundChallenges in measuring dynamic scapular orientation limit assessment of scapulothoracic and glenohumeral contributions to shoulder function in children with brachial plexus birth injury (BPBI). Double calibration acromion marker cluster (D-AMC) and linear model approaches have been validated to estimate scapular motion in healthy adults, but neither has been evaluated in BPBI. Research questionAre the linear model and D-AMC approaches able to accurately estimate scapular orientation in children with BPBI at functional arm postures? MethodsSeventeen children with BPBI positioned their affected limbs in 11 static positions while their segment orientations were measured with motion capture. Linear model and D-AMC estimates of scapular orientation were compared against palpation at six of the static positions with functional relevance to BPBI using a three-way repeat measures ANOVA and a comparison of root mean square errors (RMSE) against literature AMC values for healthy adults. ResultsThe D-AMC was similar to palpation across all positions and scapular axes while the linear model differed from palpation in a few instances. RMSEs of the D-AMC (3.7–14.8°) and particularly the linear model (4.6–24.8°) were generally at or beyond the upper range of past AMC analyses on healthy adults (1.6–14.2°), especially for more complex, multiplanar arm postures. Despite the D-AMC outperforming the linear model, this approach still produced clinically meaningful (>10°) errors for roughly (12.7–22.5%) of subjects. SignificanceCurrent methods for estimating dynamic scapular orientation remain less than ideal for BPBI. Use of the D-AMC may be appropriate to gain broad insights into general dynamic scapulothoracic and glenohumeral function; however, given their potential for producing clinically meaningful errors, the D-AMC and linear model are not recommended for diagnostic purposes or outcomes assessment on an individual patient basis unless their patient-specific accuracy has been evaluated and confirmed prior to use.

3D measurement of clavicular and scapular orientations: The association with clinical characteristics and responsiveness to scapular repositioning in patients with neck pain

BackgroundClavicular and scapular orientations vary between neck pain patients as do clinical features and responses (changes in pain and rotation range) to scapular repositioning. Associations between these factors are unknown. ObjectivesTo identify subgroups of neck pain patients based on three-dimensional (3D) measures of clavicular and scapular orientations and differences between subgroups in clinical characteristics and responses to scapular repositioning. DesignCross-sectional study. MethodsEligible participants were recruited as part of a larger study. The 3D clavicular and scapular orientations were analyzed on the more painful side of the neck using a hierarchical cluster analysis. Clinical characteristics were neck pain location, intensity, duration, disability and presence of headache. Responses to scapular repositioning were classified as “yes and no”. ResultsFifty-eight participants (29 responsive; 29 non-responsive to scapular repositioning) participated in the study. Analysis identified two distinct subgroups: subgroup1 had greater clavicular retraction and scapular downward rotation (n = 26) and subgroup2 had greater clavicular elevation and scapular internal rotation and anterior tilt (n = 32). Headache and dominant pain in the upper neck were more frequent in subgroup 1 while dominant pain in the lower neck was frequent in subgroup 2 (p < 0.01). Most participants who responded positively to scapular repositioning (88.5%) were in subgroup1 and most non-responsive participants (81.2%) in subgroup2. ConclusionsThe 3D clavicular and scapular orientations identified two subgroups of neck pain patients. Participants with predominantly downward scapular rotation were distinguished by pain in the upper neck, presence of headache and a positive response to scapular repositioning.

A randomized controlled trial of scapular exercises with electromyography biofeedback in oral cancer patients with accessory nerve dysfunction.

This study aims to investigate the effects of electromyography (EMG) biofeedback on scapular positions and muscle activities during scapular-focused exercises in oral cancer patients with accessory nerve dysfunction. Twenty-four participants were randomly allocated to the motor-control with biofeedback group (N = 12) or the motor-control group (N = 12) immediately after neck dissection. Each group performed scapular-focused exercises with conscious control of scapular orientation for 3months. EMG biofeedback of upper trapezius (UT), middle trapezius (MT), and lower trapezius (LT) was provided in the motor-control with biofeedback group. Scapular symmetry measured by modified lateral scapular slide test; shoulder pain; active range of motion (AROM) of shoulder abduction; upper extremity function; maximal isometric muscle strength of UT, MT, and LT; and muscle activities during arm elevation/lowering in the scapular plane were evaluated at baseline and the end of the intervention. After the 3-month intervention, only the motor-control with biofeedback group showed improving scapular symmetry. Although both groups did not show significant improvement in shoulder pain, increased AROM of shoulder abduction and muscle strength of the UT and MT were observed in both groups. In addition, only the motor-control with biofeedback group had improved LT muscle strength, upper extremity function, and reduced UT and MT muscle activations during arm elevation/lowering. Early interventions for scapular control training significantly improved shoulder mobility and trapezius muscle strength. Furthermore, by adding EMG biofeedback to motor-control training, oral cancer patients demonstrated greater effectiveness in stabilizing scapular position, muscle efficiency, and upper extremity function than motor-control training alone. Institutional Review Board: This study was approved by the Chang Gung Medical Foundation Institutional Review Board (Approval No: 201901788A3. Approval Date: 2 January, 2020). This trial was registered at ClinicalTrials.gov (ClinicalTrials.gov ID: NCT04476004. Initial released Date: 16 July, 2020).

Comparison of scapular alignment in auto rickshaw drivers with and without neck pain: A pilot study

Background: Auto rickshaws form 10-20% of daily motorized urban transport and ensure connectivity and easy access throughout congested Indian cities. Mostly used body parts in driving areas are the neck and shoulders. The musculature attaching the shoulder girdle to the axial skeleton is primarily responsible for scapular orientation. The overuse and improper support of muscles in this region is caused due to poor posture resulting in pain between the shoulder blade and neck; also discomfort between Scapula. Increased muscle activation of the neck- shoulder stabilizers result in higher levels of cervical spine loading; which results in neck pain. This study aimed to examine scapular alignment in auto rickshaw drivers with and without neck pain. Objective: To determine the difference in scapular alignment in auto rickshaw drivers with and without neck pain. Methodology: This observational study was conducted in 20 auto rickshaw drivers within the age group of 20-50 years and were divided into two groups. Group A included subjects with neck pain and Group B without neck pain on basis of the Numerical Pain Rating Scale. Scapular distance was measured using Lateral Scapular Slide Test (LSST) in 3 positions viz. at rest, with hands on hip and 900 of shoulder abduction and were compared using the independent t-test. Results and Conclusion: Statistically significant difference of scapular alignment in auto rickshaw drivers with neck pain was noted (p< 0.05). Hence, it was concluded that scapular alignment is altered in auto rickshaw drivers with neck pain as compared to those with no neck pain.

The reliability of the scapular posture and scapular dyskinesis tests in rugby union players.

Impact forces during rugby can contribute to scapula dysfunction and shoulder pain. Reliable assessment of static and dynamic scapula position is paramount in managing athletes with, and those at risk of developing, shoulder pain. To determine the reliability of static scapular posture (SP), clavicular tilt angle (CTA) and the scapular dyskinesis (SD) assessments by expert and student therapists. The study design was an inter-rater and intra-rater reliability study in male university level rugby union players. Four sport rehabilitation students and one experienced physiotherapist evaluated the position of the scapular and clavicle of male university-level rugby union players (inter-rater participants: session 1: n=17, session 2: n=12 and session 3: n=16; (intra-rater participants: n = 12). Participants attended 3 testing sessions, each 1 week apart. Scapular orientation and motion were assessed in five planes of movement and using the Scapular Dyskinesis Test (SDT) respectively. The inter-rater analysis included all participants from each session, while in the intra-rater analysis included only the 12 participants who attended all three testing sessions. Kappa coefficient values and percentage agreement ratings for students compared to the experienced therapist were: SP=poor to fair (-0.01 to 0.33), (27% - 94%); SDT=slight (0.16; 41%); CTA=fair (0.21; 59%). Test-retest (intra-rater) agreement was fair to moderate (0.22 - 0.44; 69% - 95%), slight (0.12; 47%), and fair (0.39; 77%) for the SP, SDT, and CTA, respectively. Static and dynamic evaluation of the shoulder by students and an experienced therapist has poor to moderate reliability and should not be used to make clinical decisions based on observation alone.

Exercise Programs Targeting Scapular Kinematics and Stability Are Effective in Decreasing Neck Pain: A Critically Appraised Topic

Clinical Scenerio: Neck pain is a costly symptom in both civilian and military worlds. While traditional treatments include deep neck flexor stabilizing exercises, manual therapy, electrical therapy, and other nonsurgical interventions, scapular orientation and stability training has emerged as a possible tool to reduce neck pain severity. Methods that can be coached at a distance could be of value in virtual appointments or circumstances where access to a qualified manual therapist is limited. Focused Clinical Question: What is the effectiveness of including exercise programs targeting scapular kinematics and stability to decrease neck pain? Summary of Key Findings: Exercise programs targeting scapular kinematics and stability, with coaching and individualized progressions, appear to reduce neck pain severity. Clinical Bottom Line: Evidence supports the inclusion of exercises for scapular kinematics and stability at a prescription of 3 sessions per week, with a duration of 4 or 6 weeks. Exercise programs should include a "learning" or coaching phase to ensure exercises are performed as intended, and exercise progressions should be based on participant ability rather than predetermined timelines. Further research is needed to better understand the benefits of this potential strategy and the statistical impact of scapular-focused exercise interventions on neck pain in specific populations like military and athletes. Strength of Recommendation: There is 'Fair' to 'Good' evidence from 2 level 1b single-blind randomized control studies and 1 level 2b pre-post test control design study supporting the inclusion of exercise programs targeting scapular kinematics and stability to decrease chronic neck pain severity.

Age-related differences in humerothoracic, scapulothoracic, and glenohumeral kinematics during elevation and rotation motions

Age affects gross shoulder range of motion (ROM), but biomechanical changes over a lifetime are typically only characterized for the humerothoracic joint. Suitable age-related baselines for the scapulothoracic and glenohumeral contributions to humerothoracic motion are needed to advance understanding of shoulder injuries and pathology. Notably, biomechanical comparisons between younger or older populations may obscure detected differences in underlying shoulder motion. Herein, biplane fluoroscopy and skin-marker motion analysis quantified humerothoracic, scapulothoracic, and glenohumeral motion during 3 static poses (resting neutral, internal rotation to L4-L5, and internal rotation to maximum reach) and 2 dynamic activities (scapular plane abduction and external rotation in adduction). Orientations during static poses and rotations during active ROM were compared between subjects <35 years and >45 years of age (N = 10 subjects per group). Numerous age-related kinematic differences were measured, ranging 5–22°, where variations in scapular orientation and motion were consistently observed. These disparities are on par with or exceed mean clinically important differences and standard error of measurement of clinical ROM, which indicates that high resolution techniques and appropriately matched controls are required to avoid confounding results of studies that investigate shoulder kinematics. Understanding these dissimilarities will help clinicians manage expectations and treatment protocols where indications and prevalence between age groups tend to differ. Where possible, it is advised to select age-matched control cohorts when studying the kinematics of shoulder injury, pathology, or surgical/physical therapy interventions to ensure clinically important differences are not overlooked.

Effects of Conscious Control of Scapular Orientation in Oral Cancer Survivors With Scapular Dyskinesis: A Randomized Controlled Trial.

Objectives:Spinal accessory nerve dysfunction is one of the complications of neck dissection in patients with oral cancer. This study aimed to explore the effects of long-term scapular-focused exercises and conscious control of scapular orientation on scapular movement and quality of life (QoL).Methods:This study was a randomized controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Thirty-six patients with oral cancer were randomly allocated to the motor-control group (scapular-focused exercise + conscious control of scapular orientation) or the regular-exercise group (scapular-focused exercises only). Both groups received conventional physical therapy after neck dissection for 3 months. Shoulder pain intensity, active range of motion (AROM) of shoulder abduction, scapular muscle strength and activity under maximal voluntary isometric contraction (MVIC), scapular muscle activity when performing scapular movements, and QoL were measured at baseline, 1 month after the start of the intervention, and the end of the intervention.Results:Both groups showed significant improvement in all outcomes except shoulder pain intensity. After the 3-month intervention, the motor-control group had more significant improvement in AROM of shoulder abduction with a 19° difference (95% CI: 10-29, P < .001), muscle strength of upper trapezius with an 11 N difference (95% CI: 2-20; P = .021), and QoL than the regular-exercise group. When performing shoulder horizontal adduction and flexion, the relative value (%MVIC) of serratus anterior was smaller in the motor-control group with a 106%MVIC difference (95% CI: 7-205, P = .037).Conclusions:Scapular-focused exercises have promising effects on spinal accessory nerve dysfunction. Combining scapular-focused exercises with conscious control of scapular orientation has more remarkable benefits on AROM of shoulder abduction, UT muscle strength, and muscle activation pattern than the scapular-focused exercises alone. Conscious control of scapular orientation should be considered to integrate into scapular-focused exercises in patients with oral cancer and scapular dyskinesis.Trial registry name and URL, and registration number: ClinicalTrials.gov (URL: https://clinicaltrials.gov; Approval No: NCT03545100)

Neck Position Affects Scapular Orientation in a Posture of Simulated Rugby Tackling

Neck Position Affects Scapular Orientation in a Posture of Simulated Rugby Tackling

An individualized linear model approach for estimating scapular kinematics during baseball pitching

Assessment of scapulothoracic and glenohumeral contributions to shoulder function during baseball pitching are limited by challenges in accurately measuring dynamic scapular orientation. A recently validated individualized linear model approach that estimates scapular orientation based on measurable humerothoracic orientation has yet to be adapted for pitching and may improve upon currently recommended methods such as the acromion marker cluster (AMC). This study evaluates the ability of a pitching-specific individualized linear model to estimate scapular orientation in static positions throughout a throwing motion by comparing against palpation and an AMC. Individualized linear models were created for 14 collegiate pitchers by determining scapulothoracic and humerothoracic orientations at static arm postures throughout their individual dynamic throwing motions. Linear model and AMC estimates were compared against palpation at intermediate test positions within the throwing motion that were excluded from model creation. Linear model estimates were similar to palpation at all test positions and on all scapulothoracic axes while AMC estimates differed on internal/external rotation and anterior/posterior tilt during cocking (p = 0.001, p = 0.018) and follow-through (p = 0.003, p = 0.006). Linear model root mean square error (RMSE) values were smaller than AMC values for all positions/axes. Linear model RMSE values (2.8–6.3°) were within a range of published values previously deemed acceptable, while AMC values (5.1–15.8°) went beyond this range. The linear model approach accurately estimates static scapular orientation throughout a pitching motion and improves upon current methods. Future applications to dynamic pitching may facilitate understanding of how scapulothoracic and glenohumeral joint function relate to injury risks, rehabilitation, and performance.

Clinical Factors Related to Improved Scapular Control After a Scapular Conscious Control Program in Symptomatic Overhead Athletes: Secondary Analysis of a Randomized Controlled Trial.

Background:Predictive variables associated with the effects of a scapular conscious control program should be identified and used to guide rehabilitation programs.Purpose:To determine whether potential factors are associated with the success of scapular muscle balance with an early control program in patients with subacromial pain and scapular dyskinesis.Study Design:Case-control study; Level of evidence, 3.Methods:A total of 38 amateur overhead athletes with subacromial pain and medial border prominence were recruited. They performed progressive conscious control of scapular orientation during 45° and 90° of arm elevation. Stepwise logistic regression and receiver operating characteristic curve were used to determine the optimal cutoff point of related factors for success or failure of the program. Potential factors including pain level during activity, pain duration, anterior/posterior shoulder flexibility, forward shoulder posture, posterior displacement of root of spine and inferior angle, scapular kinematics, and muscle activation before conscious control program were recorded as independent variables. Successful control defined as decreases of the upper trapezius/serratus anterior ratio in 2 consecutive trials of the 90° program or failure in the program was used as a dependent variable.Results:Having a posterior displacement of the inferior angle of the scapula of ≤16.4 mm and scapular posterior tipping during arm elevation of ≤3.3° (collected before the control program) were associated with the success of the program (R 2 = 0.286; P < .05). Additionally, participants with each or both variables present at baseline had probabilities of success of 78% and 95%, respectively.Conclusion:The value of scapular posterior displacement and posterior tilt should be considered before early scapular control program. Other factors related to the success of the program should be found due to the limited variance explained in the regression model.

Mid-term outcomes of reverse shoulder arthroplasty using the alternate scapular line baseplate orientation for glenoid bone loss

BackgroundGlenoid-sided bone loss poses a challenge when performing reverse shoulder arthroplasty. Placing the baseplate in an anteverted position along the alternate scapular line is an option when dealing with glenoid erosion or cavitary defects. Although this allows for stable initial baseplate fixation, questions remain about the effects of placing the baseplate in a more anteverted position relative to the standard glenoid center line. The purpose of this study was to evaluate the mid-term outcomes of patients treated with reverse shoulder arthroplasty using an alternate scapular line baseplate orientation in the setting of glenoid bone loss. Materials and methodsFrom September 2007 to March 2014, 71 patients underwent reverse shoulder arthroplasty using the alternate scapular line baseplate orientation and had a minimum of 5 years of follow up. Patients with no prior surgery, prior nonarthroplasty surgery, and prior arthroplasty surgery were included in this analysis. Patients were followed clinically (American Shoulder and Elbow Surgeons score, Simple Shoulder Test score, range of motion analysis, patient satisfaction) as well as radiographically, with data recorded at the 2-year point and their last recorded follow-up after a minimum of 60 months. ResultsAt the final follow-up point (average 78 months) patients had maintained their improvement in American Shoulder and Elbow Surgeons score (75 [P<.0001]), Simple Shoulder Test score (7.8 [P < .0001]), forward elevation (1300 [P < .0001]), external rotation (310 [P < .0001]) with no change in internal rotation (62% with full IR [P = 1.0]). No significant deterioration in outcome scores or motion was noted between the 2-year and final follow-up time point. At final follow-up, 92% remained satisfied with their outcome. There was a 7% complication rate (3 acromial fractures, 1 hematoma, 1 dislocation), with 1 patient requiring revision surgery secondary to instability. ConclusionUtilizing the alternate scapular line baseplate orientation in cases with glenoid bone loss resulted in clinical improvements with no deterioration in outcome scores, range of motion or patient satisfaction at a minimum of 5 years of follow-up. Anteverting the baseplate in this position allowed for stable glenoid-sided fixation with no mechanical failures of the baseplate and did not appear to compromise the patient's functional outcomes. In patients with significant glenoid bone loss, where adequate bone stock along the standard glenoid line may be in question, use of the alternate scapular line for baseplate orientation is an effective option yielding sustained clinical improvements and a low rate of complications. Level of evidenceLevel IV; Case Series; Treatment Study