Glenohumeral External Rotation Research Articles

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

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

Utilizing the Pronated Forearm Technique for Measuring Glenohumeral External Rotation in Baseball Players.

Alterations in glenohumeral internal rotation (GIR), glenohumeral external rotation (GER), and total range of motion (TROM) have been linked with increased injury risk. GER capacity has been measured routinely with the forearm in neutral rotation (GERN), but a recent study reported GERN was greater than GER with the forearm in pronation (GERP) in Minor League pitchers. This work has not yet been replicated or extended to other groups. GERP would be significantly less than GERN in Independent League baseball pitchers, and there would be no difference in GERP or GERN measurements between this new group and the previous group of Minor League pitchers. Cross-sectional study. Level 3. Goniometric measurements were recorded for bilateral GIR, GERN, and GERP, and resulting TROM for 37 Independent League baseball pitchers. These data were compared with the previous study. All motions were compared individually between groups, between throwing and nonthrowing arm, and both within and between techniques (forearm neutral or pronated). GERP was significantly less than GERN for both arms within each group tested (P < 0.01). Independent League pitchers had greater between arm differences for GIR (-16.9° vs -6.9°), GERN (+15.1° vs -0.6°), and GERP (+13.1° vs -5.9°) compared with Minor League pitchers. TROM for the Independent League pitchers was not statistically different for either measurement technique, while TROM for the throwing arm of the Minor League pitchers was statistically reduced with varying effect sizes (d = 0.35-0.99) compared with the nonthrowing arm (P < 0.01). This study confirmed earlier findings that the pronated forearm resulted in decreased GER capacity, illustrating the adaptive response to throwing and the need to evaluate for this variable. GERP should be evaluated in all groups of pitchers, but there may be variations within tested groups.

The associations of physical parameters with the Closed Kinetic Chain Upper Extremity Stability Test, the Upper Quarter Y Balance Test, and the Upper Limb Rotation Test in professional overhead athletes

ObjectiveTo investigate the associations of glenohumeral internal (IR) and external rotation (ER), horizontal adduction (HA), and thoracic spine rotation ranges of motion (ROM), isometric muscle strength of the shoulder rotators, and trunk muscle endurance with the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), the Upper Quarter Y Balance Test (YBT-UQ), and the Upper Limb Rotation Test (ULRT) in overhead athletes. DesignCross-sectional study. SettingsLaboratory. ParticipantsOne hundred twenty-one athletes were enrolled. Main outcome measuresIndependent variables were: IR, ER, HA, and thoracic spine rotation ROMs, isometric muscle strength of glenohumeral IR and ER muscles, and trunk muscle endurance. Dependent variables were: CKCUEST, YBT-UQ, ULRT. ResultsIR ROM of the nondominant side was associated with the CKCUEST, the YBT-UQ, and the ULRT. IR muscle strength of the dominant side was associated with the CKCUEST and the ULRT. Trunk flexor and lateral endurance of the dominant side were associated with the CKCUEST and the YBT-UQ, respectively. ConclusionsMany of the physical parameters influencing scores on the CKCUEST and the YBT-UQ are different. Common parameters influence the CKCUEST and ULRT scores, yet more parameters influence the CKCUEST score. We suggest the combined use of the CKCUEST and the YBT-UQ in overhead athletes.

Effectiveness of a joint mobilizations protocol for shoulder subacromial pain syndrome: A pilot study

BackgroundSubacromial pain syndrome (SPS) is the most frequent shoulder pathology. The aims of this prospective randomized study were to evaluate the effects of some specific shoulder joint mobilizations (“spin correction”), and the effectiveness of a rehabilitation program, named Shoulder Global Concept, in SPS patients. Methods45 patients with SPS were randomly assigned to two groups, to benefit from a different first session of mobilizations: the experimental group received all specific mobilizations, while the control group received the same program but without the spin correction mobilizations. The second session was identical for both groups, with all specific mobilizations. Before and after the first two sessions, range of motion (ROM) in flexion, abduction, external and internal rotations, pain and functional status with Constant score and Quick Dash were evaluated. Evaluation was repeated with 24 patients after 11 rehabilitation sessions. Rehabilitation with Shoulder Global Concept included 13 mobilizations aiming at improving the ROM with passive and active-assisted mobilizations, static stretching, and muscle strengthening. ResultsAll ROM were improved at the end of the first session for both groups, but significantly more in the experimental group for glenohumeral (GH) abduction and external rotation (p < 0.05). Functional scores, pain and strength were significantly improved after 11 rehabilitation sessions with the Shoulder Global Concept. ConclusionThis manual therapy method was able to improve shoulder mobility in one session. The additional joint mobilizations (spin correction) specifically increased GH abduction and external rotation. Rehabilitation of SPS with Shoulder Global Concept allowed to improve functional capacity and decrease pain.

Reliability and validity of modified upper limb neurodynamic tests in patients with cervical radiculopathy.

Neurodynamic Tests (NDTs) are used to assess neural mechanosensitivity in various conditions such as neural sliding, tension or inflammatory dysfunction. But in some upper quadrant dysfunctions, standard testing procedure of NDT cannot be assessed or tolerated by patient. The purpose of the study was to determine the validity, intra-rater and inter-rater reliability of modified NDTs via median and ulnar nerve in patients with cervical radiculopathy. Thirty-three patients (18 men and 15 women, mean age ± SD ) with cervical radiculopathy having positive response to standard NDTs were included in the study. Modified neurodynamic tests for median & ulnar nerve were performed with modification in the sequencing of standard neurodynamic test at lower degrees of glenohumeral abduction and external rotation. Outcome measures used were angle of elbow extension for median nerve and angle elbow flexion for ulnar nerve at the point of pain onset indicated by "OP" (Onset of Pain). Reliability of OP was evaluated using measurement of Intra-class Correlation Coefficient (ICC), Standard Error of Measurement (SEM) and Minimal Detectable Change (MDC) values. Results indicated high ICC values and low SEM values for OP during modified median and modified ulnar NDTs (M-MNT1 and M-UNT) on symptomatic side of patients with cervical radiculopathy. Spearman correlation analysis for validity of test score showed strong correlation () with standard NDT. There was strong correlation between Modified NDTs and standard tests depicting good validity and substantial reliability of OP during M-MNT1 and M-UNT for positive NDT response in patients with cervical radiculopathy.

Observational assessment for determining shoulder fault movements before and after corrective education in participants with chronic shoulder pain: Concurrent validity study

BackgroundMovement faults (MF), described as the alteration of joint position and motion, are an important factor associated with developing shoulder pathologies. However, determining or predicting the exact MF in participants with shoulder pain is limited by the absence of clinical tools and poor validity. PurposeThe aim of the study was to determine the validity of using observational assessment to MFs or controlling MFs in subjects with chronic shoulder pain during shoulder elevation and external rotation. Study DesignConcurrent validity study MethodsTwenty-seven people with chronic shoulder pain were examined. The index test represented three observational assessments of MF during shoulder external rotation, elevation in the frontal plane, and elevation in the sagittal plane. Three-dimensional motion analysis represented the reference test. The movements of both shoulder joints were evaluated simultaneously, and the index and reference tests were performed concurrently. ResultsThe sensitivity and specificity of observational detection were good to excellent (Se: 77.5%, Sp: 81.5%) for MF and excellent (Se: 85.7%, Sp: 100%) for controlling MF. The positive and negative predictive value was (PPV: 93.9, NPV: 57.1) for MF and (PPV: 100%, NPV: 82.8%) for controlling MF. The result of the positive and negative likelihood ratio was (PLR: 5.4, NLR: 0.26) for MF and (PLR: 0, NLR: 0.18) for controlling MF. ConclusionsThe results revealed that the validity of the observational detection approach for identifying MFs was good to excellent. Moreover, the accuracy of this approach in detecting the control of MFs after patient education was excellent. There was good to excellent accuracy in most MFs once classified by their motion trajectories, except for scapula anterior tilt during glenohumeral joint external rotation or elevation.

Throwing Shoulder Adaptations Are Not Related to Shoulder Injury or Pain: A Preliminary Report.

Overhead throwing in baseball and softball athletes induces shoulder adaptations theorized to increase risk of shoulder musculoskeletal injury (MSI) and/or pain due to range of motion (ROM) deficits. Shoulder ROM adaptations are associated with a higher risk for developing shoulder MSI and pain. Prospective cohort study. Level 3. A total of 60 National Collegiate Athletic Association Division I athletes cleared for full athletic participation and free from upper extremity MSI in the last 4 weeks (age, 19.0 ± 1.2 years; weight, 82.1 ± 13.7 kg; height, 178.6 ± 11.2 cm; softball, n = 23; baseball, n = 37). Passive glenohumeral internal rotation (IR), external rotation (ER), and horizontal adduction (HA) ROM were measured with the scapula stabilized and used to categorize participants with/without external rotation gain (ERG), external rotation insufficiency (ERI), glenohumeral internal rotation deficit (GIRD), pathological GIRD, and posterior shoulder tightness (PST) before the competitive season. Groups were then compared to assess the incidence of shoulder MSI prospectively and prevalence of shoulder pain at the initial evaluation. Baseball and softball athletes demonstrated significantly less IR ROM in the dominant shoulder (50.6° ± 9.4°) compared with the nondominant shoulder (59.1° ± 8.6°; P < 0.01) and significantly more ER ROM (dominant, 104.6° ± 12.1°; nondominant, 97.7° ± 12.0°; P < 0.01). Incidence of shoulder MSI was 15% but was not significantly related to any shoulder adaptations. No significant relationship was found between prevalence of pain and any shoulder adaptations in the 27% of athletes with pain. Increased ER and decreased IR ROM adaptations in intercollegiate overhead throwing athletes do not appear to be correlated to risk of shoulder MSI or pain. The findings of this level 3 prospective study provide clinicians working with overhead athletes information regarding shoulder MSI risk and pain. It is recommended that clinicians should not use ROM adaptations exclusively to determine increased risk of shoulder MSI.

Evaluation of the role of intra-articular corticosteroids on improvement of range of motion in adhesive capsulitis

Adhesive capsulitis is often described by restricted glenohumeral elevation and external rotation, together with unremarkable radiographic findings, are also observed. The condition is commonly reported burden of middle age between 40 and 65 and is rare in children age group and in manual workers with it being slightly more common in women (3.38 women and 2.36 men per thousand person years). Nowadays, there are many intervention options that are accessible for PAS, manipulation under anaesthesia which the shoulder is freed by rotation while the patient is under short general anaesthesia. This can be undertaken as a day procedure, exercise therapy, electrotherapy, hydrotherapy etc as well as pharmacotherapy and surgery. The present study was done to compare sub- acromial and rotator interval approach of corticosteroid injection in patients with adhesive capsulitis of the shoulder joint and evaluate the improvement in the ROM in such patients.

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

Excess and repetitive glenohumeral external rotation (ER) is at a higher risk for shoulder injuries, which occurs frequently in professional sports and specific occupations. Current rehabilitation programs emphasize selective targeting of muscle activity, which can help restore dysfunctional muscle imbalances or prevent injuries. However, the impact of different body postures on GH muscle activity during ER exercises has not been fully understood. Therefore, the purpose of this study was to investigate shoulder EMG activity for different body positions and humeral abduction angles during ER exercises. Twenty-three healthy young men (age: 22.3 ± 2.3, height: 175.75 ± 4.02, mass: 75.37 ± 9.14) participated in this study. Surface Electromyography was recorded from seven shoulder muscles: upper trapezius, lower trapezius, serratus anterior, infraspinatus, and deltoid. Six ER exercises: three postures (sitting, supine lying, and prone lying) and two abduction angles (ABD; 45° and 90°) were tested using an isokinetic dynamometer. During a sitting position, the lower trapezius/upper trapezius muscle activity ratios were significantly increased for sitting compared to supine lying and prone lying (p < 0.001, p = 0.004). Serratus anterior/upper trapezius co-contraction indices were significantly increased for 90° than 45° ABD (p < 0.001). These findings can provide insight into new training programs aimed at restoring GH muscle imbalances.

Poster 161: Musculoskeletal Adaptations to Baseball Pitching Differ Markedly Between Righthand Dominant Versus Lefthand Dominant Pitchers

Objectives: Musculoskeletal adaptations on the dominant arm of baseball pitchers are typically (1) a gain in glenohumeral external rotation (ER) range of motion (ROM), (2) a loss of glenohumeral internal rotation (IR) ROM, (3) posterior shoulder tightness, (4) weakness in the empty can test, and (5) increased IR strength. The purpose of this study was to determine if these adaptations differed between righthand dominant (RHD) versus lefthand dominant (LHD) pitchers. Based on recent work it was hypothesized that ROM adaptations would be less apparent in LHD pitchers, but strength adaptations would not differ between RHD and LHD pitchers. Methods: Shoulder ROM and strength were measured in 327 baseball pitchers in preseason screening (91 were tested on more than one season, 418 player-seasons, 322 RHD vs. 96 LHD). There were 157 youth pitchers (age 11-15 yr) 146 adolescent pitchers (age 16-17 yr) and 115 adult pitchers (age 18-24 yr). ER ROM, IR ROM and posterior shoulder ROM (Tyler test) were measured with a digital level. Empty can, ER, IR and scapular retraction strength were measured with a hand-held dynamometer. Differences between the dominant and nondominant arms, between RHD and LHD pitchers, and between age groups, were assessed using mixed model analysis of variance (mean and SD reported). Results: ROM Adaptations RHD pitchers had 11±10° more ER ROM on the dominant versus nondominant arm (P&lt;0.001) but LHD pitchers had no ER ROM difference (0±10°, P=0.685). The difference in ER ROM between RHD and LHD pitchers (P&lt;0.001) was unaffected by age (P=0.829). IR ROM loss on the dominant versus nondominant arm for RHD pitchers (10±11°) was greater (P&lt;0.001) than for LHD pitchers (5±10°). This difference was apparent for youth pitchers (RHD 9±9° vs. LHD 1±9°, P&lt;0.001) and adolescent pitchers (RHD 12±10 vs. LHD 5±11°, P&lt;0.001) but not for adult pitchers (RHD 9±14° vs. LHD 8±10°, P=0.863; RHD vs. LHD by Age Group P=0.040). Total ROM (ER+IR ROM) adaptations also differed between RHD and LHD pitchers (P&lt;0.001) and this effect was more apparent in the adult pitchers (Age Group by RHD vs. LHD P=0.027): RHD adult pitchers had a 4±15° gain in total ROM on the dominant side (P=0.007) while LHD adult pitchers had a 7±10° loss in total ROM on the dominant side (P=0.002). Posterior shoulder tightness on the dominant side was affected by arm dominance and age (P=0.038); for youth and adolescent pitchers there was no difference between RHD and LHD pitchers (youth RHD 6±13° vs. LHD 10±11°, P=0.156; adolescent RHD 5±10° vs. LHD 8±15°) but for adult pitchers, posterior shoulder tightness was greater for RHD versus LHD pitchers (6±8° vs. 1±11°, P=0.032). Strength Adaptations For the empty can test, RHD pitchers were weaker on the dominant versus nondominant arm (5±15%, P&lt;0.001) while there was no difference between the dominant and nondominant arms for LHD pitchers (3±16% stronger on dominant side P=0.100; RHD vs. LHD P&lt;0.001). For IR strength, RHD pitchers were stronger on the dominant arm (7±17%, P&lt;0.001) while there was no difference between the dominant and nondominant arms for LHD pitchers (2±21% P=0.360; RHD vs. LHD P=0.032). By contrast, for scapular retraction strength, LHD pitchers were stronger on the dominant arm (6±19%, P=0.007) while there was no difference between the dominant and nondominant arms for RHD pitchers (0±15% P=0.723; RHD vs. LHD P=0.003). Dominant versus nondominant ER strength was not different between RHD and LHD pitchers (P=0.323). Conclusions: The typical strength and ROM adaptations seen in baseball pitchers were mostly absent, or diminished, in LHD pitchers, but with some age dependent effects for ROM. Adult RHD pitchers had IR ROM loss and posterior shoulder tightness, but paradoxically adult LHD pitchers had IR ROM loss without associated posterior shoulder. The opposite was the case for youth and adolescent pitchers, with LHD pitchers having posterior shoulder tightness in the absence of IR ROM loss. Differences in strength adaptations between RHD and LHD pitchers have not been reported previously. Epidemiological studies examining the role of strength and ROM in injury risk for baseball pitchers have not previously accounted for differences between lefthanded and righthanded pitchers.

Paper 17: Decreased Glenohumeral External Rotation is associated with Elbow Injury in Adolescent Baseball Pitchers

Objectives: To compare bilateral standard glenohumeral range of motion, humeral torsion &amp; humeral torsion-corrected glenohumeral range of motion within and between healthy adolescent baseball pitchers &amp; adolescent baseball pitchers who have an injury to the throwing elbow. Secondarily, to analyze the relationship between humeral torsion angle and glenohumeral rotational motion in adolescent pitchers. Methods: Baseball pitchers aged 13-17 were prospectively enrolled into either a healthy group, if currently pitching in the community without complaint or injured group, if they presented to clinic for an elbow injury related to pitching. Bilateral standard glenohumeral internal &amp; external rotation was measured in degrees using a bubble goniometer with the scapulothoracic joint manually stabilized. Bilateral humeral torsion angles were measured using an Ultrasound &amp; bubble goniometer and were used to calculate humeral torsion-corrected glenohumeral range of motion. Parametric tests were used to compare values within and between groups for both the dominant and non-dominant extremities with significance defined as p&lt;0.05. Pearson’s correlation was used to evaluate the relationship between humeral torsion and standard glenohumeral motion in each group. Results: Twenty-nine healthy and twenty-five injured pitchers were enrolled with no difference in age or hand dominance between groups. The dominant shoulder of both the healthy (Table 2) and injured (Table 3) groups demonstrated a significant increase in humeral retrotorsion with increased standard glenohumeral external rotation &amp; GIRD. However, no difference in humeral torsion-corrected range of motion was present within groups. Injured pitchers displayed less standard &amp; humeral torsion-corrected external rotation of the dominant shoulder as well as less standard external rotation of the non-dominant shoulder compared to the healthy pitchers (Table 4). No difference in internal rotation measurements or humeral torsion was found between groups. A moderate correlation was found between ipsilateral humeral torsion angle and standard glenohumeral external (r=0.49) &amp; internal rotation (r=-0.58) in the dominant shoulder of healthy pitchers (Figure 1) but no correlation (r&lt; 0.3) was found between these measures in the dominant shoulder of injured pitchers. Conclusions: Both healthy &amp; injured adolescent baseball pitchers displayed dominant shoulder GIRD, external rotation gain &amp; retrotorsion of the humerus. In healthy pitchers, dominant glenohumeral motion was correlated to the humeral torsion angle suggesting that the osseous adaptation of humerus significantly contributed to these findings. However, this correlation was not found in the injured pitchers, suggesting that soft tissue factors played a larger role in the development of GIRD &amp; external rotation gain in this group. Additionally, injured pitchers displayed less standard glenohumeral external rotation of both shoulders and less humeral torsion-corrected external rotation of the dominant shoulder compared to healthy pitchers. This suggests a baseline difference in the soft tissue and/or structure of the pitchers’ shoulders between groups. Glenohumeral internal rotation and humeral retrotorsion were not associated with injury status in our study. Clinically, this study suggests that rehabilitation programs including modalities to improve external rotation may be of benefit for adolescent baseball pitchers with elbow injuries &amp; further research on the structural variations of the adolescent pitching shoulder is needed. [Table: see text][Table: see text][Table: see text]

Effect of Scapular Retraction on Lower Trapezius, Infraspinatus, and Deltoid Muscle Electromyographic Activity During the Side-Lying Abduction Exercise.

The lower trapezius (LT) muscle, which stabilizes the scapula posteriorly during arm elevation, has been interesting to both clinicians and researchers for its importance in throwing-related shoulder rehabilitation and injury prevention. The purpose of this study was to investigate the electromyographic activity of the LT and other relevant muscles during scapular and shoulder activities in the side-lying position. Twenty collegiate baseball players volunteered to participate in this study. Electromyographic (EMG) output of the lower trapezius, infraspinatus, posterior deltoid, middle deltoid, serratus anterior, and upper trapezius muscles were collected. All the subjects performed isometric resistance exercises in four arm positions: 0° horizontal abduction from the coronal plane (NEUT) with protraction (NEUT-PRO), 15° horizontal adduction from the coronal plane (HADD) with protraction (HADD-PRO), and NEUT with retraction (NEUT-RET), and HADD-RET in a side-lying isometric abduction exercise with two external loads: a 9.1 kg dumbbell and 40% of the manual muscle test (MMT). The subjects also performed two more isometric resistance exercises: supine protraction and side-lying external rotation (ER) of the glenohumeral (GH) joint in GH adduction at 90° of GH ER or with as much ER as possible. All raw EMG data were normalized to maximal voluntary isometric contraction (% MVIC) of the corresponding muscle. LT activity was significantly greater in HADD-RET with 9.1 kg than that of HADD-PRO (p < 0.001) (55 vs 21% MVIC) while middle deltoid muscle activity was significantly decreased in both NEUT and HADD-RET compared to that of NEUT and HADD-PRO (p < 0.001). In contrast, IS muscle activity was significantly increased in HADD-RET with 9.1 kg compared with that 40% MMT (p < 0.001) (41 vs 22% MVIC). LT activity was modulated by changes in scapulothoracic and glenohumeral joint positioning during a side-lying isometric abduction exercise. These findings may help clinicians to select exercises to improve scapular muscle balance ratios during rehabilitation of the shoulder complex. Level 3b, Controlled laboratory study.

Complete Restoration of Native Glenoid Width Improves Glenohumeral Biomechanics After Simulated Latarjet

Background: The amount of glenoid width that must be restored with a Latarjet procedure in order to reestablish glenohumeral stability has not been determined. Purpose/Hypothesis: The purpose of this article was to determine the percentage of glenoid width restoration necessary for glenohumeral stability after Latarjet by measuring anterior humeral head translation and force distribution on the coracoid graft. The hypothesis was that at least 100% of glenoid width restoration with Latarjet would be required to maintain glenohumeral stability. Study Design: Controlled laboratory study. Methods: Nine cadaveric shoulders were prepared and mounted on an established shoulder simulator. A lesser tuberosity osteotomy (LTO) was performed to allow accurate removal of glenoid bone. Coracoid osteotomy was performed, and the coracoid graft was sized to a depth of 10 mm. Glenoid bone was sequentially removed, and Latarjet was performed using 2 screws to reestablish 110%, 100%, 90%, and 80% of native glenoid width. The graft was passed through a subscapularis muscle split, and the LTO was repaired. A motion tracking system recorded glenohumeral translations, and force distribution was recorded using a TekScan pressure sensor secured to the glenoid face and coracoid graft. Testing conditions included native; LTO; Bankart tear; and 110%, 100%, 90%, and 80% of glenoid width restoration with Latarjet. Glenohumeral translations were recorded while applying an anteroinferior load of 44 N at 90° of humerothoracic abduction and 0° or 45° of glenohumeral external rotation. Force distribution was recorded without an anteroinferior load. Results: Anterior humeral head translation progressively increased as the proportion of glenoid width restored decreased. A marked increase in anterior humeral head translation was found with 90% versus 100% glenoid width restoration (10.8 ± 3.0 vs 4.1 ± 2.6 mm, respectively; P < .001). Greater glenoid bone loss also led to increased force on the coracoid graft relative to the native glenoid bone after Latarjet. A pronounced increase in force on the coracoid graft was seen with 90% versus 100% glenoid width restoration (P < .001). Conclusion: Anterior humeral head translation and force distribution on the coracoid graft dramatically increased when <100% of the native glenoid width was restored with a Latarjet procedure. Clinical Relevance: If a Latarjet is unable to fully restore the native glenoid width, surgeons should consider alternative graft sources to minimize the risk of recurrent instability or coracoid overload.

Effects of an 8-week multimodal program on thoracic posture, glenohumeral range of motion and serve performance in competitive young tennis players.

Intensive tennis practice is known to generate sport-specific adaptations at the shoulder region and influence the sagittal spinal curvature. However, increased thoracic kyphosis decreases the shoulder functional capacity, which could limit tennis performance. Therefore, the aim of this study was to investigate the effects of an 8-week multimodal program on thoracic posture, glenohumeral range of motion, and serve performance in competitive young tennis players. Eighteen male and four female players (age: 16.0 ± 2.4 years, height: 170.7 ± 11.0 cm; mass: 62.1 ± 11.5 kg; International Tennis Number: 3-4) performed their regular training during 8 weeks, which was used as a reference period, and implemented a multimodal program including stretching, strengthening, and myofascial release exercises, four times per week during 8 additional weeks, which corresponded to the intervention period. The thoracic curvature angle and mobility, the biacromial and interscapular distances, the glenohumeral range of motion and the tennis serve performance were assessed three times, i.e., before and after the regular training and after the 8-week multimodal program. The results showed that the 8-week regular training had no significant effects on thoracic curvature angle [effect size (ES) = 0.02-0.36, p = 0.06-0.46] and mobility (ES = 0.05-0.26, p = 0.13-0.42), biacromial (ES = 0.05, p = 0.18) and interscapular distances (ES = 0.03, p = 0.45), ranges of motion in glenohumeral internal (ES = 0.04, p = 0.43) and external rotation (ES = 0.43, p = 0.06), and tennis serve accuracy (ES = 0.33, p = 0.07) and velocity (ES = 0.09, p = 0.35). The 8-week multimodal program increased moderately the thoracic mobility (ES = 0.55, p = 0.01), moderately to strongly the serve accuracy and velocity (ES = 0.65, p = 0.003, for both), strongly decreased the interscapular distance (ES = 1.02, p < 0.001), and strongly increased the range of motion in glenohumeral internal (ES = 0.90, p < 0.001) and external rotation (ES = 1.49, p < 0.001). These findings indicated that an 8-week multimodal program, including spine and glenohumeral mobility and shoulder girdle strength exercises, performed four times per week during 8 weeks, is moderately relevant to rectify the sagittal thoracic curvature in competitive tennis players, while such a program may help regain the range of motion in glenohumeral rotation without tennis serve performance impairment.

Functional Deficits After Open Latarjet Procedure and Dominance of the Operated Shoulder: An Analysis of 133 Patients

Background: Return to sport after stabilization surgery using the open Latarjet procedure remains challenging. Additional knowledge is needed about postoperative shoulder functional deficits in order to better design return-to-sport programs. Purpose: To investigate the effects of the dominance status of the operated shoulder on the shoulder functional profile recovery at 4.5 months after open Latarjet procedure. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective analysis of prospectively collected data was performed. All patients who underwent the open Latarjet procedure between December 2017 and February 2021 were eligible for the study. Functional assessment at 4.5 months after the surgery was performed using the following tests: maximal voluntary isometric contractions in glenohumeral internal and external rotation, upper-quarter Y balance test, unilateral seated shot-put test, and modified closed kinetic chain upper extremity stability test, leading to 10 outcome measures. Patients whose dominant side had undergone surgery and those whose nondominant side had undergone surgery were compared with a group of 68 healthy control participants. Results: A total of 72 patients who underwent an open Latarjet procedure on the dominant side and 61 patients who underwent open Latarjet on the nondominant side were compared with 68 healthy control athletes. In patients whose dominant shoulder had undergone surgery, significant deficits for the dominant side (P < .001) and for the nondominant side (P < .001) were found in 9 of 10 functional outcome measures. Among patients whose operations were on the nondominant shoulder, significant deficits for the nondominant side (P < .001) and for the dominant side (P < .001) were found in 9 and 5 of the 10 functional outcome measures, respectively. Conclusion: Regardless of dominance of the stabilized shoulder, persistent deficits in strength, stability, mobility, power, and stroke frequency were observed at 4.5 months postoperatively. Stabilization of the dominant shoulder resulted in residual surgery-related functional impairments on both sides. However, stabilization of the nondominant shoulder resulted in impairments primarily noted in the nondominant, operative shoulder. Registration: NCT05150379 (ClinicalTrials.gov identifier).

Mechanistic insights into glenohumeral kinematics derived from positional relationship between the contact path and humeral tuberosity

Although three-dimensional (3D) glenohumeral (GH) motion has generally been expressed only by rotational elements, its mechanistic details, including GH rotations, remain unknown owing to a lack of geometric investigations. This study aims to investigate the positional relationship between the contact path and humeral tuberosities at the GH joint during arm elevation and to consider the mechanism of GH kinematics. Shoulder kinematics were captured using two-dimensional and 3D single-plane image registration techniques in 15 young healthy subjects during flexion, scaption, and abduction. The glenoid movement relative to the humeral head was calculated to describe the contact path on the humeral head. From the start to 45° of flexion, scaption, and abduction, the glenoid center moved from the anteromedial to the anterior, central, and posterior portions of the humeral head, respectively, as the GH joint rotated externally. From 45° to the maximal elevation for all elevation planes, the glenoid center moved upward to the humeral head and came close to the bicipital groove (BG) at maximal elevation, while the glenoid maintained a constant inclination at 20°–40° relative to the humerus. To investigate this mechanism, the position of humeral tuberosities relative to the glenoid was calculated, and the BG was found to face the supraglenoid tubercle, the attachment site of the long head of biceps (LHB). GH external rotation mainly occurred depending on the elevation planes in the early phase of elevation, and it might be kept constant by the LHB and rotator cuff in the mid- to end range of elevation.

The relationship between scapular position and glenohumeral rotational range of motion in high school baseball players.

Past research indicated that scapular malposition is related to the glenohumeral internal rotation deficit (GIRD). However, there is no research examining the effect of throwing-related pain on this relationship. This study investigated the relationship between scapular position and range of motion (ROM) and compared the difference in this relationship between with and without throwing-related pain. Forty male baseball players in high school were recruited for this study. The existence and degree of throwing-related pain were obtained from a questionnaire. Participants were divided into 2 groups according to the presence or absence of the pain. Glenohumeral internal and external rotation ROM (abduction internal rotation angle and abduction external rotation angle [ABER], respectively) were measured using a digital inclinometer. The pectoralis minor muscle length was measured using a vernier caliper and scapula index, which indicated the scapular position, measured using a measuring tape. All these measurements were taken on both dominant and nondominant sides. The GIRD and total motion arc (TMA) deficit were calculated from the ROM measurements. Groups were compared using a mixed-model analysis of variance. There was a significant interaction between group and ABER dominance. Other variables were not seen as the interaction effect. There was a significant positive correlation between the scapula index and TMA (r=0.47, P=.02) and a negative correlation between the scapula index and GIRD (r=-0.65, P<.01) in the dominant side of the pain group. In addition, in the nondominant side of the pain group, the scapula index and ABER were significantly correlated (r=0.43, P=.04). The results of this study indicate that the scapular position is associated with the glenohumeral ROM in high school baseball players. In addition, this study demonstrated that the scapular internally rotated position was correlated with the GIRD and TMA deficit in high school baseball players who had throwing-related pain. On the other hand, the scapular externally rotated position was correlated with increased ABER, mainly in the pain-free baseball players or on the nondominant side. These results indicated that the scapular position might affect the glenohumeral rotational ROM in high school baseball players.

Comparison of High-grade Maitland Mobilization and Post Isometric Relaxation (PIR) Muscle Energy Technique on pain, range of motion, and functional status in patients with Adhesive Capsulitis

Aim: To compare the effect of post isometric relaxation (PIR) muscle energy technique and high-grade Maitland mobilization technique on pain, glenohumeral joint abduction and external rotation, and functional activities in the subject of frozen shoulder. Study design: Randomized control trial Methods: A total of 60 patients were initially assessed for eligibility and 52 were included in the study after taking written consent. Patients were divided into two groups; Group A was treated with post isometric relaxation (PIR) technique and group B with Maitland grade (IV) mobilization for 4 weeks. Pain with a Numeric Pain rating scale, Glenohumeral joint abduction and external range of motion with a goniometer and shoulder function with shoulder pain and disability index were evaluated. Results: Both groups were similar at baseline (p&gt; 0.05) and within-group comparison has shown that there was a significant improvement in all variables in both groups as p&lt;0.05, but between-group comparison has shown that post-isometric relaxation (PIR) was more effective in reducing pain, improving range of motion and functional status and the mean difference between both groups for pain was 1.96, for shoulder abduction was 24.88, for external rotation was 10.42 and for SPADI was 23.27 with p&lt;0.05 for all, showing that post isometric relaxation (PIR) muscle energy technique is superior to the Maitland grade IV mobilization technique in improving pain, Glenohumeral joint range, and shoulder function. Conclusion: Both Post isometric relaxation (PIR) and Maitland Mobilization are effective but post isometric relaxation (PIR) muscle energy technique is superior to the Maitland grade IV mobilization technique in improving pain, Glenohumeral joint range, and shoulder function. Keywords: Adhesive capsulitis, Maitland mobilization technique, Muscle energy technique, Shoulder pain and disability

Effect of thoracic expansion restriction on scapulothoracic and glenohumeral joint motion during shoulder external rotation.

Shoulder external rotation in the throwing motion involves movement of the scapulothoracic and glenohumeral joints, thoracic spine, and the thorax. Restriction of thoracic expansion may decrease scapulothoracic joint motion and compensate by excessive glenohumeral joint motion. However, it is unclear how restricting the expansion of the thorax alters shoulder motion. To elucidate changes in scapulothoracic and glenohumeral joint movements caused by restricted thoracic expansion. Kinematic data were obtained using an electromagnetic tracking device (Liberty; Polhemus), from 18 male participants, during shoulder external rotation in the sitting position with and without restriction of thoracic expansion. The displacements from the start position to the maximum external rotation position were compared, and Pearson's correlation coefficient was calculated. A significant difference was observed in the scapulothoracic posterior tilt angle (P< 0.01) and glenohumeral external rotation angle (P< 0.01). A significant positive correlation existed between scapulothoracic posterior tilt and glenohumeral external rotation (P< 0.05) with and without restriction. Restriction of thoracic expansion decreased scapulothoracic motion and increased glenohumeral motion. Thus, a decrease in thoracic expansion may change scapulothoracic and glenohumeral movements, which may be a risk factor for throwing injuries.

Shoulder Kinematics of Axillary Web Syndrome in Women Treated for Breast Cancer

ObjectiveTo better understand how the shoulder moves in breast cancer survivors with axillary web syndrome (AWS), we compared 3-dimensional (3D) shoulder kinematics during shoulder elevation among breast cancer survivors with and without AWS 5 years postoperatively. Although research consistently shows decreased shoulder range of motion with AWS, we do not understand the underlying biomechanics. DesignNested case control study. SettingUniversity Academic Breast Center. ParticipantsTwenty-five women who had surgery 5 years previously for unilateral breast cancer with the removal of at least 1 lymph node participated in this study (N=25). Twelve participants had AWS; 13 women did not have AWS. InterventionsNot applicable. Main Outcome MeasuresThree-dimensional shoulder kinematic data during shoulder forward flexion, scapular plane abduction, and coronal plane abduction were collected using 3D electromagnetic motion tracking. Kinematic data were extracted at 30°, 60°, 90°, and 120° of arm elevation for scapular upward rotation, internal rotation, and posterior tilt as well as for glenohumeral external rotation. ResultsWomen with AWS demonstrated 15.2° less scapular upward rotation at 120° humerothoracic elevation (95% confidence interval [-25.2, -5.2], P=.005), regardless of plane. No significant between-group differences were found for any other angle of scapular upward rotation, nor for scapular internal rotation, scapular posterior tilt, or glenohumeral axial rotation at any angle. ConclusionsFive years after surgery for breast cancer, women diagnosed with AWS have altered scapulohumeral kinematics that may place them at an increased risk of shoulder pain based on existing kinematic literature in healthy cohorts. This information can help guide rehabilitation programs for breast cancer survivors to facilitate pain-free upper extremity function after treatment.