Scapular Plane Research Articles

The Effect of Scapular Orientation on Measures of Rotator Cuff Tendon Impingement: A Simulation Study.

Mechanical impingement of the rotator cuff tendons against the acromion (subacromial) and glenoid (internal) during shoulder motions has long been thought to contribute to tears. Clinically, the risk for impingement is thought to be influenced by scapular movement impairments. Therefore, our purpose was to determine the extent to which simulated changes in scapular orientation impact the proximity between the rotator cuff tendon footprint and the acromion and glenoid during scapular plane abduction. Specifically, shoulder kinematics were tracked in 25 participants using a high-speed biplane videoradiography system. Scapular movement impairments were simulated by rotating each participant's scapula from their in vivo orientation about the scapular axes (±2°, ±5°, and ±10°). Subacromial and internal proximities were described using minimum distances, proximity center locations, and prevalence of contact. Statistical parametric mapping was used to investigate the extent to which these measures were impacted by simulated changes in scapular orientation. Simulated changes in scapular orientation significantly altered proximity patterns in a complex manner that depended on the impingement mechanism, humerothoracic elevation angle, and magnitude of the simulated change. Clinicians should be mindful of these factors when interpreting the potential effects during a clinical examination.

Effectiveness of Retraction 30 over Gross Stretch For Relieving Pectoralis Minor Tightness Among College Students

Background: The Pectoralis minor muscle originates from different 3 ribs and converges into one attachment point. Pectoralis minor shortening can contribute to many syndromes and impairments, especially at the shoulder. Some of them are impingement of the soft tissues, adhesive capsulitis etc. The prevalence of pectoralis minor tightness is very high in college-going students. The gross stretch is the stretching procedure that increases the length of the pectoralis minor muscle. This shoulder position produces tension in the muscle insertion in a posterior direction in conjunction with the scapular motion that is performed at flexion and elevation in the scapular plane, thereby lengthening the muscle. Retraction 30 is stretching with scapular retraction at 30 degrees of shoulder flexion; the flexion angle at 30 degrees can lengthen the muscle along the muscle fiber direction in the coronal plane. 30 degrees of flexion is considered to be more comfortable than a higher angle of flexion, as well as the angle is closest to the line of force Objectives of the study: To compare the effectiveness of gross stretch and retraction 30 in relieving pectoralis minor muscle tightness which can be co-operated in further treatment protocols. Study Design: Comparative Study Methodology: Two group pre–test–post–test design was used with purposive sampling. Selected subjects were allocated to two groups. Fourty subjects (20 males and 20 females) who fulfilled inclusion and exclusion criteria were recruited for the study. The independent variables are gross stretch and retraction 30 whereas the dependent variables were PMI (pectoralis minor index), pectoralis minor length test and Cervical Curvature. Result: This study results imply that retraction 30 is better when compared to gross stretch for correcting pectoralis minor tightness. Hence should be included as an inevitable part of stretching treatment. Practicing clinicians should continue to use evidence-based decisions when treating pectoralis minor tightness.

Isolated humeral distalization in reverse total shoulder arthroplasty: a biorobotic shoulder simulator study

BackgroundHumeral distalization is inherent to reverse total shoulder arthroplasty (rTSA) and is often produced with concomitant humeral lateralization via the level of the humeral head cut, implant positioning, implant neck shaft angle, and polymer insert thickness. Biomechanical data on the isolated effects of humeral distalization remain limited but could be important to consider when optimizing postoperative rTSA shoulder function. This study investigated the effects of isolated humeral distalization on shoulder biomechanics using a biorobotic shoulder simulator. MethodsEight fresh-frozen cadaveric shoulders were tested using custom polymer inserts that translated the bearing surface 0, +5, +10, and +15 mm along the humeral stem axis, producing isolated distalization without lateralization. Specimens underwent passive elevation in the scapular plane with a static scapula to assess glenohumeral range of motion. Scapular plane abduction motion trajectories were then performed, driven by previously collected scapulothoracic and glenohumeral kinematics from rTSA patients. The effect of isolated distalization on passive elevation was tested using mixed-effects linear regression and the effect on muscle force, joint reaction force, and muscle excursion during active scapular-plane abduction was tested using statistical parametric mapping random effects analysis. ResultsMaximum passive scapular plane elevation increased with humeral distalization (4° per 5 mm distalization). During active elevation, deltoid and rotator cuff muscle forces, and joint reaction forces, increased up to 37% per 5 mm of distalization. Simulated deltoid muscle excursion was altered with increasing distalization but amounted to no more than 0.8 mm change from baseline per 5 mm of distalization. Rotator cuff muscles were consistently lengthened throughout abduction, up to 1.6 mm per 5 mm of distalization. These trends were observed across various patient motions. ConclusionsIsolated humeral distalization caused dramatic increases in the muscle forces required to perform scapular-plane abduction. Joint reaction forces increased correspondingly. These results suggest that implant and surgical strategies to generate deltoid muscle tension without humeral distalization may promote better active range of motion and more durable long-term outcomes over approaches that rely on distalization.

The open Latarjet procedure does not affect scapulohumeral rhythm three months postoperatively

BackgroundAlthough it is considered a sensitive indicator of shoulder disabilities, the scapulohumeral rhythm has not been investigated after anterior glenohumeral stabilization with open Latarjet procedure. This study aimed to assess the short-term influence of glenohumeral stabilization on scapulohumeral rhythm in patients who underwent open Latarjet procedure compared to asymptomatic individuals. MethodsA group of male patients who underwent anterior glenohumeral stabilization by open Latarjet procedure and a healthy group were enrolled in this study. An electromagnetic device was used to record scapulothoracic and glenohumeral joint kinematics during dynamic arm elevation and depression in the scapular plane before and three months after surgery. Then, the three-dimensional dynamic scapulohumeral rhythm was computed bilaterally. SPM ANOVAs were used for statistical analysis. FindingsTwenty-two participants per group were included. The scapulohumeral rhythm of the two groups increased from 1.88 [mean] ± 0.79 [standard deviation] to 2.83 ± 1.52 during the ascending phase, while a decrease followed by a slight increase in the scapulohumeral rhythm were observed during the descending phase. The scapulohumeral rhythm did not significantly differ between the operated and non-operated sides or before and after surgery. When pooling the sides for each group, no significant differences were observed between the groups. InterpretationThe scapulohumeral rhythm in patients who underwent the Latarjet procedure is not modified three months after surgery and is similar to the scapulohumeral rhythm of asymptomatic individuals. These findings suggest that in addition to restoring glenohumeral stability, the open Latarjet procedure preserves shoulder joint coordination three months postoperatively.

Nonspherical humeral arthroplasty increases internal rotation: a biomechanical comparison of the native humeral head to nonspherical and spherical humeral implants

BackgroundNonspherical humeral head implants more closely resemble native humeral anatomy than spherical components and may better replicate native shoulder range of motion (ROM) and kinematics. The purpose of this study was to compare shoulder ROM and kinematics of a commercially available nonspherical humeral head implant with the native humeral head and a height matched, custom manufactured spherical implant. MethodsSix fresh frozen cadaveric shoulder specimens were used with a custom shoulder testing system. The native shoulder was tested in multiple positions under anatomic muscle loading. Each specimen was tested for ROM and glenohumeral joint kinematics by measuring the humeral head apex and humeral head center (HHC) translation per degree of rotation using a MicroScribe digitizer. Measurements were then repeated after implantation of a spherical and, subsequently, a nonspherical humeral head prothesis. ResultsThe nonspherical implant had significantly more internal rotation (IR) compared to the spherical implant at 0° abduction (10.6 ± 6.2° more IR, P = .004, 95% confidence interval [CI]: −13.3, 34.5), 30° abduction (5.7 ± 2.8°, P = .009, 95% CI: −12.6, 24.0) and 60° abduction (6.8 ± 2.7°, P = .002, 95% CI: −8.3, 22.1) in the scapular plane, and 60° abduction (6.9 ± 2.0°, P = .031, 95% CI: −12, 25.6) in the coronal plane. The nonspherical implant had more IR than the native head at 60° of abduction in the scapular plane (7.0 ± 2.2° P = .002, 95% CI: −10.3, 24.3). The spherical head had less IR than the native head at 0° abduction (7.2 ± 4.8°, P = .031, 95% CI: 32.5, 18.1). There were no differences in humeral head apex translation per degree of rotation noted between the spherical implant or nonspherical implant and the native shoulder. The nonspherical head had less HHC translation than the native shoulder at 30° abduction in the forward flexion plane (P = .007); otherwise, there were no statistically significant differences in HHC translation between the native shoulder, the spherical head, and the nonspherical head. There was no significant difference observed between the average difference in anterior-posterior and superior-inferior radius of curvature of the nonspherical implants (2.0 ± 0.7 mm) and the native humeral heads (1.9 ± 1.3 mm) [P = .926]. ConclusionThe results of this biomechanical study suggest that the commercially available nonspherical humeral head has improved IR when compared to a custom, height controlled spherical implant and offers ROM and kinematics similar to the native humeral head in a cadaveric model.

Head-Shaft Angle Influences Isometric Shoulder Strength Levels after Intramedullary Nailing of Proximal Humerus Fractures: A Pilot Study.

Proximal humerus fractures are common fractures of the elderly population which can lead to long-term compromise of a patient's shoulder function. Closed reduction and internal fixation with intramedullary nailing is a well-established surgical technique yielding good outcomes, as perceived by patients, obtained via Patient-Reported Outcome Measures, and objectified by clinical shoulder testing. Apart from conventional range-of-motion testing and clinical shoulder tests, strength testing of the shoulder is a yet-neglected but meaningful and standardizable outcome parameter. In this study, isometric shoulder strength is evaluated in relation to fracture morphology/postoperative reduction quality as well as with patient-reported outcomes. 25 patients (mean age 73.2 ± 10.5 years) underwent isometrics strength-testing of the shoulder joint in the scapular plane (abduction) as well as in the sagittal plane (flexion) as well as hand-grip strength-testing at 4.5 ± 1.88 years follow-up. Pre- and postoperative radiographs were analysed. Patients completed ASES and CMS questionnaires. Patients exhibited a decrease in abduction and flexion force (-24.47% and -25.30%, respectively, p < 0.001) using the contralateral, uninjured arm as reference. Abduction force tended to be decreased in three- and four-part fractures. Patient satisfaction correlated negatively with the relatively reduced force of the affected arm. Varus-angulated humeral heads produced significantly lower abduction force output than valgus- or physiologic angulation (p = 0.014), whereas flexion force was unaffected (p = 0.468). The anatomical reduction had no influence on shoulder strength. Proximal humerus fractures may cause a significant reduction in shoulder function, both reported by patients and objectified by shoulder strength testing. Varus head angulation demonstrated the greatest loss of shoulder strength and should be avoided to ensure proper functioning. Further, strength testing seems a valuable outcome parameter for a thorough shoulder examination with easy obtainability.

B2 and B3 glenoid osteoarthirtis: outcomes of corrective and concentric (C2) reaming of the glenoid combined with pyrocarbon hemiarthroplasty

Posterior humeral subluxation (PHS) in B2/B3 glenoid is a cause of asymmetric long-term stress on the glenoid and the potential reason for glenoid loosening in anatomic total shoulder arthroplasty (ATSA) and painful glenoid erosion in hemiarthroplasty with metallic heads (HA-Metal). We hypothesized that corrective and concentric reaming (CCR) of the glenoid associated with pyrocarbon hemiarthroplasty (HA-PYC) could improve the centering of the humeral head and decrease the risk of persistent painful glenoid erosion in young/active patients with B2/B3 glenoid. Between 2014 and 2020, 41shoulders (in 35 patients, mean age of 57.9 years) underwent HA-PYC combined with CCR reaming for B2 (n=30) or B3 (n=11) osteoarthritis. Patients were prospectively followed with computed tomography (CT) scans performed preoperatively, immediate postoperatively and at last follow-up (> 2 years). The primary outcomes were 3D-corrected CT-scan measurements of glenoid version, PHS, progression of glenoid erosion. Secondary outcomes included functional outcome scores, return to activities, and revision rate and complications. At a mean follow-up of 4.5 years (2 to 9.5 years), the prosthesis survival was 95% (39/41). No patient has been reoperated for painful glenoid erosion. The mean glenoid retroversion decreased from 17.1° ± 7.5 preoperatively to 8.3° ± 8.2 at last follow-up (p=0.001), and the mean PHS from 74% to 56.5% (p=0.001) based on the scapular plane and from 59.9% to 50.3% based on the glenoid plane. The humeral head was recentered in 97% according to the glenoid surface and 71% according to the scapular plane. Correction of PHS in the scapular plane was highly correlated to correction of glenoid retroversion (p<0.001). CT-scan measurements showed that the average total medialization was 3.7 ± 3.2 mm (2.0 ± 1.8 mm due to reaming and only 1.7 ± 2.4 mm due to erosion). The Adjusted Constant score increased from 43% ± 13 to 97% ± 16 and the Subjective Shoulder Value from 38% ± 14 to 84 % ± 12 (p<0.001). Overall, 84% of active patients returned to work and all patients returned to sports. In B2/B3 glenoid arthritis, corrective, concentric glenoid reaming combined with HA-PYC improves centering of the humeral head and shows a low risk of painful glenoid erosion at mid-term follow-up. The combined procedure results in excellent functional outcomes and high prosthesis survivorship at mid-term follow-up. HA-PYC and CCR is offering an alternative shoulder arthroplasty for young/active patients with B2/B3 glenoid osteoarthritis who want to return to work or sports practice.

Poster 139: A Prospective, Observational Study to Assess the Efficacy of BioEnthesis in Patients Undergoing Arthroscopic Rotator Cuff Repair

Objectives: Rotator cuff repair (RCR) remains an area needing further research to optimize patient outcomes postoperatively. This study investigates a novel allogenic, acellular, biphasic cancellous bone scaffold that lies between the tendon and bone in an RCR. The purpose of this study is to assess the efficacy of this graft in improving the integration of soft tissue to bone post RCR. Methods: Ten patients were consented to receive the BioEnthesis graft prior to undergoing arthroscopic RCR. Patients received an MRI and patient reported outcomes (PROs) preoperatively and at 6 and 12-months postoperatively. A control cohort was obtained from a previous randomized controlled trial and matched in a 2:1 ratio by sex, tear size, and number of anchors used in the repair. The control cohort had an MRI at 12-months only. Two reviewers (R.D., A.B.Y.) independently graded each MRI according to the Sugaya classification assessing post-operative rotator cuff repair as well as a binomial assessment for the presence of a retear. Results: Analysis included 10 patients (7 male, 3 female) receiving the BioEnthesis graft and 20 Control patients (14 male, 6 female). The BioEnthesis cohort was significantly older than the Control cohort (69.7 ± 5.9 vs 56.11 ± 9.4; p&lt;0.001). At 12-months postoperatively, there was a trend in the average Sugaya score graded on MRI favoring the BioEnthesis over the Control cohort (2.28 ± 1.2 vs 3.3 ± 1.09; p=0.054). BioEnthesis patients had a lower rate of retear on 12-month MRI, but this difference was not significant (29% vs 45%; p=0.23). No significant differences were found for PRO’s at any time point. VAS was not assessed for the control group, however, BioEnthesis patients significantly improved from pre-operative to 12-months post-operative (5.0 ± 2.4 to 0.875 ± 0.8; p&lt;0.001). BioEnthesis patients experienced significant strength increases in abduction, scapular plane abduction, and external rotation at 6 and 12-months postoperatively. Conclusions: The BioEnthesis graft is a safe graft option that may reduce the risk of retear and help the integration of tendon to bone in arthroscopic RCR.

Relationship between scapular body morphology and rotator cuff tears: a threedimensional computed tomography study.

The purpose of this study was to identify the relationship between scapula morphology and rotator cuff tears (RCT). Hundred seventeen shoulders with and 87 shoulders without RCTs were included in this retrospective study. The critical shoulder angle (CSA) and lateral acromion angle in the coronal view, and the acromial coverage angle (ACA) and coracoid and scapular spine angle (CSSA) in the sagittal view were evaluated using 3-dimensional computed tomography. The glenoid anterior tilt, anterior acromial projection angle (AAPA), coracoid process angle, scapular spine angle (SSA), and inferior angle angle (IAA) with respect to the scapular plane were measured in the sagittal view. In univariate logistic regression analysis, CSA, ACA, AAPA, SSA, and IAA were significantly greater in shoulders with RCTs, whereas CSSA was greater in shoulders without RCTs. In multivariate logistic regression analysis, CSA and IAA were greater in shoulders with RCT and were significantly associated with this condition (P=.00073, P=.0032). This study has shown us that RCTs were associated with a greater curvature of the scapular body and greater CSA and IAA.

Inferior glenohumeral joint capsule thickness in frozen shoulder via ultrasonography

BackgroundThe thickening of the inferior glenohumeral joint capsule (IGC) is a characteristic finding in frozen shoulders. However, the relationship between the thickness of the IGC measured using ultrasonography (US) and the range of motion (ROM) remains unclear. This study aimed to investigate a suitable IGC thickness measurement site that can reflect the ROM of frozen shoulders. MethodsThe participants were Twenty-nine patients with frozen shoulder and 20 healthy shoulders of 10 healthy adult. US measurements of the IGC were performed at 80° elevation in the scapular plane, with thickness was measured at three levels in both groups: just above the surgical neck, just above the anatomical neck, and at the parenchymal level. The relationship between thickness and ROM at the three levels was also assessed. The thickness of the IGC was evaluated using MRI and US, as well as the validity of US evaluation. ResultsThere was a positive correlation (r=0.72) between MRI- and US-measured IGC thickness. The IGC was thicker in the frozen shoulder group than in the control group at all three levels (p<0.001). The thickness of the IGC at the parenchymal level showed a significant negative correlation with all ROMs: flexion (r = −0.63), abduction (r = −0.60), external rotation (r = −0.50), and internal rotation (r = −0.52). ConclusionThe thickness of the IGC at the parenchymal level is negatively correlated with the ROM. The evaluation of the IGC in this study will be helpful in selecting treatment options for frozen shoulders.

Association Between Scapular Dyskinesis and Forward Head Posture in Badminton Player: A Cross-Sectional Study

Objective: To determine the association between scapular dyskinesis and forward head posture among badminton players. Methodology: An analytical cross-sectional study was conducted recruiting 120 recreational badminton players using non-probability convenience sampling. Badminton players of either gender, aged 18-35 years with head-forward posture were participants in the study based on the predefined eligibility criteria after ethical approval. Scapular dyskinesis was measured using the Modified Lateral Scapular Slide test in three testing positions. The data was evaluated using SPSS version 26.0 and a chi-square test was implemented to find the association, and P≤0.05 was deemed significant. Results: In resting position, Scapular Dyskinesis was evident in 39.2% of badminton players while it was 65% and 54.2% evident respectively in dynamic hands-on-hip position and scapular plane with one kg weight in both hands. In addition, out of 120 players the prevalence of moderate forward head posture was greater as compared to the mild and severe forward head posture. Scapular dyskinesis was significant in hands on hip and with one kg weight in hands position (p≤0.05). Conclusion: It was found that badminton players with forward head posture had significantly different scapular kinematics in dynamic scapular positions when compared to static scapular positions.

Periscapular Strength Profile Changes in Collegiate Baseball Pitchers Over the Course of a Season.

Repetitive application of high forces to the shoulder and scapular musculature during the pitching motion over the course of a collegiate baseball season may lead to changes in strength and increased fatigue, potentially predisposing pitching athletes to injury. The purpose of this study was to investigate periscapular strength profiles of Division I collegiate baseball players over the course of a season. This study was a retrospective data analysis of 18 Division I baseball pitchers. Isometric scapular plane abduction (scaption), external rotator, internal rotator, middle trapezius, and lower trapezius isometric strength was measured on throwing arm of each subject using a MicroFET 2 handheld dynamometer. Data were collected in a single session at the preseason, midseason, and postseason of the college baseball season, which spanned a five-month period. A repeated measures ANOVA was utilized to determine if there was a significant change in periscapular strength across the baseball season. Over the three time-points, all strength values decreased for each muscle group, with decreases ranging from 3-14%. Changes in scaption strength values were statistically significant (p=0.018, partial eta squared =0.284) with an 8% reduction over the entire season, specifically with a 5% decline from mid-season to post-season. While external rotator, internal rotator, middle trapezius, and lower trapezius strength values all decreased over the course of the season (range 0.02kg to 1.8kg), these differences were not statistically significant. However, the middle trapezius strength value change (1.3kg loss) exceeded the minimal detectible change. Periscapular muscles in baseball pitchers diminish in strength over the course of a collegiate baseball season. Understanding strength changes over the course of a season may influence training and therapeutic interventions. 3b.

Greater distance from the glenosphere center to the acromion reduces risk of acromial impingement in semi-inlay reverse shoulder arthroplasty

BackgroundRecently, the issue of subacromial notching, caused by acromial impingement has been reported. The purpose of this study was to assess the impact of differences in the distance between the glenosphere center and the greater tuberosity (DGT) and the distance between the glenosphere center and the acromion (DA) on the closest distance between the greater tuberosity and the acromion during active abduction in shoulders with reverse total shoulder arthroplasty (RSA). MethodsEleven shoulders with semi-inlay RSA were analyzed. Subjects underwent fluoroscopy during active scapular plane abduction. Computed tomography of their shoulders was performed to create 3-dimensional implant models at a mean of 16 months after surgery. Using model-image registration techniques, poses of 3-dimensional implant models were iteratively adjusted to match their silhouettes with the silhouettes in the fluoroscopic images (shape matching), and 3-dimensional kinematics of implants were computed. The closest distance between the acromion and greater tuberosity was computed at maximum abduction. DA and DGT were measured from 3-dimensional surface models. Shoulders were divided into two groups based on DA and DGT measurements and their closest distance data were compared between the groups. ResultsThere were 7 shoulders with DA ≥ DGT, and 4 shoulders with DA < DGT. Shoulders with DA ≥ DGT showed a significantly wider distance between the greater tuberosity and acromion at maximum abduction compared to those with DA < DGT (5.9 ± 2.4 mm vs. 0.6 ± 0.7 mm, respectively, P = 0.0021). There were no significant differences in maximum glenohumeral abduction angle and humeral abduction angle between the two groups. Although DA was significantly greater in shoulders with DA ≥ DGT than in those with DA < DGT (43.7 ± 4.4 mm vs. 35.1 ± 6.7 mm, respectively, P = 0.0275), there was no significant difference in DGT between the two groups. ConclusionsWhen DGT is less than DA in shoulders with RSA, the closest distance between the greater tuberosity and the acromion at maximum abduction is significantly wider compared to cases where DGT is greater than DA by 3-dimensional measurement. Therefore, acromial impingement is less likely to occur in shoulders with RSA when DA is greater than DGT. To avoid acromial impingement, it might be important to make DA greater than DGT.

DYNAMIC STABILITY DURING REPETITIVE AXIAL GLENOHUMERAL ROTATION USING CINE MRI IN HEALTHY ADULTS

Manual testing for dynamic shoulder instability includes noting and shifting of the humeral head, but the corresponding shift of the axis of rotation has been given little attention. The purpose of this study is to clarify translation of the humeral head during active glenohumeral rotation. Magnetic resonance images were taken at 2[Formula: see text]images/s on 22 shoulders of 11 healthy men. At [Formula: see text] shoulder elevation, the supine subject internally and externally rotated the humerus repeatedly over 20[Formula: see text]s. The location over the glenoid of the center of the humeral head (CENHED) projected was studied. During external rotation, projection of CENHED on the glenoid began posterior to the center of the glenoid and migrated to anterior. During internal rotation, this projection was initially positioned above the glenoid center and midway through the motion, shifted inferiorly to nearly the glenoid center. The projection of CENHED did not significantly differ in location over the glenoid at any position along the range of motion during shoulder rotation. Initial values are now available for judging excessive movements of the humeral head on the glenoid fossa during rotation at [Formula: see text] of abduction in the scapular plane. The method used in this study is amenable to clinical use.

The Kouvalchouk procedure vs. distal tibial allograft for treatment of posterior shoulder instability: the deltoid “hammock” effect exists

BackgroundIn 1993, Kouvalchouk described an acromial bone block with a pedicled deltoid flap for the treatment of posterior shoulder instability. This procedure provides a “double blocking” effect in that the acromial autograft restores posterior glenoid bone loss and the deltoid flap functions as a muscular “hammock” resembling the sling effect of the conjoint in the Latarjet procedure. The primary aim of this study was to compare the Kouvalchouk procedure to distal tibial allograft (DTA) reconstruction for the management of posterior shoulder instability with associated bone loss, while the secondary aim was to evaluate the deltoid hammock effect. s MethodsTen upper extremity cadavers were evaluated using a validated shoulder testing apparatus in 0° and 60° of glenohumeral abduction in the scapular plane. Testing was first performed on the normal shoulder state and was followed by the creation of a 20% posterior glenoid defect. Subsequently, the Kouvalchouk and DTA procedures were conducted. Forces of 0N, 5N, 10N and 15N were applied to the posterior deltoid tendinous insertion on the Kouvalchouk graft along the physiological muscle line-of-action to evaluate the ‘hammock” effect of this procedure. Testing was additionally performed on the Kouvalchouk bone graft with the deltoid muscle sectioned from its bony attachment. For all test states, a posteriorly directed force was applied to the humeral head perpendicular to the direction of the glenoid bone defect, with the associated translation quantified using an optical tracking system. The outcome variable was posterior translation of the humeral head at an applied force magnitude of 30N. ResultsThe Kouvalchouk procedure with the loaded deltoid flap (10N: P=0.039 and 15N: P<0.001) was significantly better at reducing posterior humeral head translation than the DTA. Overall, increased glenohumeral stability was observed with increased force applied to the posterior deltoid flap in the Kouvalchouk procedure. The 15N Kouvalchouk was most effective at preventing posterior humeral translation, and the difference was statistically significant compared with the 20% glenoid defect (P=0.003), detached Kouvalchouk (P<0.001), and 0N Kouvalchouk (P<0.001). The 15N Kouvalchouk procedure restored posterior shoulder joint stability to near normal levels, such that it was not significantly different from the intact state (P=0.203). ConclusionsThe Kouvalchouk procedure with load applied to the deltoid was found to be biomechanically superior to the DTA for the management of posterior shoulder instability with associated bone loss. Additionally, the results confirmed the presence and effectiveness of the deltoid “hammock” effect.

The effect of kinesio® tape on scapulothoracic joint kinematics in young healthy participants

IntroductionThe purpose of this study was to investigate the effects of Kinesio® tape on scapulothoracic joint kinematics during humerothoracic elevation and lowering in asymptomatic participants. MethodSixteen males and 24 females participated in data collection using the Polhemus G4 3D electromagnetic motion capture system. Dominant shoulder kinematics were collected while the participant performed three repetitions of elevation in the frontal, sagittal, and scapular planes. Initial data collection occurred with and subsequent data collection without Kinesio® tape. Scapular upward rotation and posterior tilting were compared between the two conditions between 30 and 90 degrees of elevation. ResultsDuring abduction elevation, participants demonstrated 3.40° more posterior tilting (p = 0.001), and 2.58° less upward rotation (p = 0.006) with Kinesio® tape. During lowering in the scapular plane, participants demonstrated 2.05° less downward rotation (p = 0.008) with Kinesio® tape. DiscussionPeople with subacromial impingement and multidirectional instability demonstrate decreased upward rotation. People with subacromial impingement also demonstrate decreased posterior tilting. Posterior tilting differences found during elevation as well as upward rotation differences found during lowering in this study indicate Kinesio® tape may be beneficial to patients with impingement or multidirectional instability. ConclusionKinesio® tape significantly alters scapulothoracic kinematics during humerus to trunk elevation. The clinical significance of this remains to be investigated.

Altered Cervical Spine Position Results in Decreased Eccentric Shoulder Rotation Strength.

Overhead athletes require strenuous shoulder activity in nonneutral cervical spine positions to eccentrically decelerate the throwing/striking arm following ball release/contact. We therefore aimed to compare eccentric shoulder rotation strength through a 90° arc between neutral and rotated positions. Fifty-two participants (19 M, 34 F 170±10 cm; 73±18 kg, 21.9±2.9 years) without shoulder or cervical spine pathology participated. Isokinetic eccentric shoulder rotation strength was measured through a 90° arc with the shoulder elevated 90° in frontal plane (frontal plane), and 45° anterior to the frontal plane (scapular plane) in neutral and rotated cervical spine positions. Cervical spine position was obtained by instructing participants to maximally rotate their respective side. Frontal plane eccentric external rotated strength differed between neutral and contralaterally positions in the first 10° of the motion, near forearm vertical (p+=+0.029). Internal rotation strength differed between neutral and contralaterally rotated positions from 55-60° external rotation (p+=+0.004). Scapular plane eccentric external rotation differed between cervical positions between 21-67° shoulder external rotation (p<0.001). Scapular plane internal rotation strength differed between cervical positions between 22-60° shoulder external rotation (p<0.001). In populations requiring strenuous use of their shoulders in altered cervical spine positions, sports medicine clinicians should consider including strength testing that reflects the functional positions of their patients during an orthopedic examination.

Return to Sports and Clinical Results After All-Arthroscopic Biceps Tenodesis Using a 2.7-mm Knotless PEEK Suture Anchor.

The long head of the biceps tendon (LHBT) is a well-known source of pain in the shoulder, especially in active patients. To evaluate the outcomes and return-to-sports rate after all-arthroscopic suprapectoral tenodesis of the LHBT using a small knotless anchor. Case series; Level of evidence, 4. In this retrospective study, 27 patients-who underwent all-arthroscopic tenodesis of the LHBT using a 2.7-mm knotless polyether ether ketone anchor-were evaluated. Sports activities, the return-to-sports rate, and other sports-related parameters (eg, pain during sports, level of sports) were examined. Sports-related data, the Constant score with isometric force (at 90° of abduction in the scapular plane), the American Shoulder and Elbow Surgeons (ASES) score, the Simple Shoulder Test (SST) score, the visual analog scale (VAS) score for satisfaction, range of motion, and the presence of a Popeye deformity were assessed at a mean follow-up of 15.3 ± 8.7 months. The data were initially analyzed using descriptive statistics. The postoperative ASES, Constant, and SST scores were 81.61, 85.74 and 8.85, respectively. Of the 27 patients, 4 patients (14.8%) showed a Popeye deformity. Preoperatively, 25 patients (92.6%) participated regularly in some type of sports activity. All 25 patients (100.0%) were able to return to sports activities after surgery. 24 (96.0%) returned to the same level preoperatively, with 88.0% (22/25) within 6 months. Patient satisfaction with the outcome was high (VAS score: 2.15 ± 2.78). Neither bicipital groove pain nor cramping was reported. There were no signs of osteolytic bone around the anchor or a fracture of the humeral bone. Our clinical results after using a 2.7-mm knotless anchor for LHBT tenodesis as well as the return-to-sports rate were satisfying. Using an anchor this size can lower the risk of cortical bone damage and therefore the risk of fractures of the humeral head while still enabling patients to perform at a high level.

Three-dimensional measurements of scapular kinematics: Interrater reliability and validation of a skin marker-based model against an intracortical pin model

A skin marker-based motion capture model providing measures of scapular rotations was recently developed. The aim of this study was to investigate the concurrent validity and the interrater reliability of the model. Shoulder range of motion (RoM) and activities of daily living (ADL) were tested in healthy volunteers with reflective markers on the scapula and thorax. To investigate the validity, the model was compared to simultaneous data collection from markers on a scapular intracortical pin. The interrater reliability was tested by comparing the skin marker-based protocol performed by two investigators. The mean root mean square error (RMSE) and the intraclass correlation coefficient (ICC(2,1)) were calculated to determine the validity and the interrater reliability, respectively. Eight subjects were included in the validity test: female/male = 2/6, mean (SD) age 35.0 (3.0) and BMI 23.4 (3.3). The mean RMSE of all scapular rotations ranged 2.3–6.7° during shoulder RoM and 2.4–7.6° during ADL. The highest errors were seen during sagittal and scapular plane flexions, hair combing and eating. The reliability test included twenty subjects: female/male = 8/12, mean (SD) age 31.4 (4.9) and BMI 22.9 (1.7). The ICC(2,1) for measuring protraction ranged 0.07–0.60 during RoM and 0.27–0.69 for ADL, for upward rotation the corresponding ICC(2,1) ranged 0.01–0.64 and 0.38–0.60, and anterior tilt 0.25–0.83 and 0.25–0.62. The validity and interrater reliability of the model are task dependent, and interpretation should be made with caution. The model provides quantitative measurements for objective assessment of scapular movements and can potentially supplement the clinical examination in certain motion tasks.

External handheld loads affect scapular elevation and upward rotation during shoulder elevation tasks

ABSTRACT Altered scapular kinematics is associated with shoulder pain. Resistance exercise is a common treatment; however, the effects of lifting an external load on scapular kinematics is limited. Understanding whether an external handheld load affects scapular kinematics in a healthy population can provide normal values utilized for comparison to individuals with shoulder pain. Currently, no studies have examined the effect of incrementally increased handheld loads. We defined the effects of varying external handheld loads on scapular kinematics during a shoulder elevation task. Healthy participants (n = 50) elevated their shoulder in the scapular plane over 4 trials. One trial of no loading (control) and 3 trials with incrementally increased external handheld loads. Scapular kinematic rotations and translations were measured during ascent and descent phases using 3D motion capture. Compared to no load, the highest external load during ascent increased scapular elevation [mean difference = 3.2 degrees (95%CI: 0.9, 5.4), p = 0.006], and during descent increased scapular elevation [mean difference = 3.9 degrees (95%CI: 2.8, 5.1), p < 0.001] and increased scapular upward rotation [mean difference = 4.5 degrees (95%CI: 2.4, 6.6), p < 0.001]. External handheld loads result in small increases in scapular elevation and scapular upward rotation. These results should be utilized as normal values to compare to individuals with shoulder pain.