Normal Shoulder Research Articles

Sex differences in shoulder acromiohumeral contact surface arc length on three-dimensional computed tomography imaging

Anatomy-based guidelines for shoulder surgery have established the routine preoperative evaluation of the humeral head. Despite recognized sex differences in humeral head size, there has been limited investigation into sex-specific variations in acromiohumeral contact surface (AHCS) arc length. This study aims to assess sex differences in the AHCS arc length within a sample of the Chinese population. We retrospectively analyzed 169 normal shoulder CT images from a single medical center, collected between 2011 and 2021. The AHCS arc length was defined as the distance from the superior glenoid tubercle to the lateral edge of the greater tuberosity, measured using a three-dimensional reconstruction algorithm. Physiological reference values for the AHCS arc length were determined at three abduction angle intervals. Linear regression analysis was used to assess the correlation between the AHCS arc length and abduction angle in both sexes. The reference values for AHCS arc length were significantly lower in women across three abduction angle intervals (male 48.07 ± 3.37 mm vs. female 43.54 ± 2.54 mm, (0–10] °, p < 0.001; male 45.07 ± 2.34 mm vs. female 40.78 ± 2.06 mm, (10–20] °, p < 0.001; male 42.08 ± 2.03 mm vs. female 38.09 ± 2.44 mm, > 20 °, p = 0.001, respectively). Additionally, the AHCS arc length was linearly and negatively correlated with the abduction angle (male R2 = 0.436, p < 0.001; female R2 = 0.434, p < 0.001, respectively). The present study identified a significant sex difference in the anatomical AHCS arc length in a sample of the normal Chinese population. Preoperative assessment of the AHCS arc length may be necessary for certain shoulder surgeries in the future.

Surface vs. skeleton: the relationship between surface topographic and radiographic measurements of shoulder symmetry in patients with scoliosis.

This study evaluates the relationship between existing radiographic measurements of shoulder asymmetry with novel surface topographic (ST) measurements, hypothesizing that these relationships will be weak. Data were gathered from a prospectively collected registry of patients who underwent ST scanning at a single tertiary care institution. Inclusion criteria were diagnosis of juvenile or adolescent idiopathic scoliosis, age 11-21, same-day ST and EOS radiographic evaluation. Twelve radiographic variables that evaluate shoulder height were measured, as well as curve magnitudes and vertebral axial rotation. ST data were collected using the 3dMDbody scanning system. Three ST measurements of shoulder symmetry were evaluated: ST-based AC angle (the angle between a line made between the surface of the AC joints and a line parallel to the ground), Shoulder Normal Asymmetry angle (the angle between the mirrored normals to the planes defined by the jugular notch, vertebral prominence, and AC joint), and Shoulder Volume Asymmetry Index (difference in volumes between the right and left shoulder). Univariate, followed by a stepwise multivariate linear regression was performed to evaluate the correlations of the radiographic measurements to the ST-based measurements. Correlation categories: weak (x < 0.4), moderate (0.4 ≤ x < 0.6), strong (0.6 ≤ x < 0.8), and very strong (x ≥ 0.8). 141 patients with idiopathic scoliosis were evaluated (65.2% female, mean age 15.1years, mean BMI 20.5kg/m2, with mean maximum curve 44.7 degrees). ST-based AC angle had moderate-to-strong correlations with several radiographic measurements, while ST-based Shoulder Normal Asymmetry angle and Shoulder Volume Asymmetry Index had weak or no correlation with individual radiographic measures. Multivariate models created using a combination of radiographic variables demonstrated a strongly positive correlation between radiographic variables and ST-based AC angle (R = 0.678) and moderately positive correlations with ST-based Shoulder Normal Asymmetry Angle (R = 0.488), and ST-based Shoulder Volume Asymmetry Index (R = 0.514). Radiographic measurements may be acceptable stand-ins for two-dimensional ST measurements such as AC angle, but not for more complex shoulder measurements based on three dimensions. This study demonstrates the inadequacy with which radiographic assessments evaluate shoulder height asymmetry and highlights the use of ST measurements.

The Critical Shoulder Angle as a Highly Specific Predictor of a Full-Thickness Rotator Cuff Tear: A Case-Control Study

Background: The critical shoulder angle (CSA) has become an important topic of study in patients with rotator cuff tears (RCTs). However, there are conflicting data on whether the CSA can differentiate between patients with normal shoulder pathology and full-thickness RCTs on shoulder radiographs. Purpose/Hypothesis: The purpose of this study was to define the relationship between full-thickness RCTs and the CSA. It was hypothesized that patients with full-thickness RCTs would have an increased CSA compared with matched controls. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This retrospective case-control study identified patients with magnetic resonance imaging scans showing full-thickness RCTs between 2009 and 2019. A 1 to 1 propensity score match was performed to identify a control group with normal rotator cuffs while controlling for baseline participant characteristics—including age, sex, body mass index, and tobacco use. A total cohort of 532 was identified, with 266 cases and 266 controls. Two independent observers measured CSAs on true anteroposterior shoulder radiographs. Results: There was no difference in baseline participant characteristics between the RCT and the non-RCT groups (P > .05). The mean CSA for the entire cohort was 33.6°± 4.2°. The CSA did not significantly vary by sex (P = .088) or tobacco usage (P = .16). The mean CSA for the RCT case group, 36.2°± 3.3°, was significantly different from the mean CSA for the control group, 30.9°± 3.3° (P < .0001). The receiver operating characteristic curve analysis produced an area under the curve of 0.88 (P < .0001). At CSAs ≥35°, there was a 67.7% sensitivity and 89.4% specificity for having a full-thickness RCT. Last, each degree of increase in the CSA increased the risk of having an associated RCT by 1.7 times (OR, 1.7 [95% CI, 1.551-1.852]; P < .0001). Conclusion: Patients with RCTs had significantly higher CSAs compared with matched controls. Increased CSA was an independent risk factor for RCTs, with an odds ratio of 1.7 per degree. The CSA is an accurate test (area under the curve, 0.88) with good sensitivity (67.7%) and specificity (89.4%) at values ≥35°. The CSA is a simple, reproducible measurement that can assist in clinical decision-making regarding full-thickness RCTs.

The impact of glenohumeral bone loss on range of motion in patients with anterior shoulder instability.

Loss of shoulder range of motion (ROM) is common after surgical management of anterior shoulder instability; however, it remains unclear to what degree this is related to their injury. The purpose of this study was to compare passive shoulder ROM in patients with ASI to a normal contralateral shoulder. A total of 121 patients undergoing stabilization surgery were prospectively enrolled. Preoperative advanced imaging was used to assess for glenoid bone loss and the presence of off-track Hill-Sachs lesions. Passive ROM was measured in both shoulders while under anaesthesia prior to surgery. In all directions, there was a significant loss of ROM in shoulders with instability. Regression analysis showed that neither a glenoid bone defect nor greater glenoid bone loss were associated with a loss of ROM in any plane. The presence of a Hill-Sachs lesion was significantly associated with a loss of external rotation, while off-track lesions were associated with a loss of ROM in all planes (p < 0.05). Patients with anterior shoulder instability lost motion in all directions, with a profound loss of external rotation. The presence of a glenoid bone defect nor greater bone loss did not reliably predict a loss of range of motion. A Hill-Sachs lesion was predictive of a loss of external rotation, while an off-track lesion was predictive of a loss of range in all directions.

The Influence of the Dominant Leg in Body Asymmetries in Children and Adolescent Male Soccer Players.

The current study aimed to examine (a) whether the dominant leg (DL) was associated with the contralateral side of functional scoliosis and (b) if any of the postural asymmetries' evaluation variables may be a reliable predictor of the functional scoliosis development in young male soccer players. Six hundred-nine (n = 609) male soccer players (age: 10.8 ± 2.7 years; height: 147 ± 17 cm; weight: 43.4 ± 14.6 kg; DL: Right 81.6%, Left 14%, Both 4.4%) participated in this study. The spinal asymmetries evaluation included thoracic kyphosis, lumbar lordosis, truncal rotation, shoulders alignment from posterior view, anterior and posterior pelvic tilt, anterior superior iliac spine (ASIS), hamstring tightness, and lower extremities discrepancy. A significant association was observed between the DL and the truncal rotation side: χ2(4) = 30.84, p = 0.001, V = 0.16. Participants with longer left legs were likelier to present a spinal asymmetry (OR = 1.18). The participants with higher left shoulders were 2.13 times more likely to have spinal asymmetry than the participants with normal shoulders level. Participants with left ASIS higher were 3.08 times more likely to present asymmetry than those with normally aligned ASIS levels. There was also a significant association between the DL and the side of truncal rotation: χ2(2) = 13.30, p = 0.001, V = 0.449. Logistic regression analysis for the functional scoliotic group and truncal rotation side demonstrated that the taller participants and participants with shorter right legs were more likely to have asymmetry on the left side (OR = 1.29, OR = 0.32). Participants with greater right hamstring stiffness were likelier to have a truncal rotation on the right side (OR = 0.93). Participants with higher left shoulders were 0.20 times less likely to have a truncal rotation on the left side than the participants with normal shoulders level. In conclusion, leg dominance in children and in youth soccer players may be a factor causing truncal rotation on the contralateral side. Additional causes, such as leg length discrepancy and pelvic tilt, may progressively lead to functional scoliosis.

A rare case report: Brucellosis as an extreme cause of shoulder subluxation and rotator cuff tendinopathy

Rationale: Shoulder subluxation and rotator cuff tendinopathy is commonly associated with degeneration or trauma, and brucellosis has been reported to be correlated with shoulder subacromial bursitis, arthritis. However, brucellosis as a cause of shoulder subluxation and rotator cuff tendinopathy has never been reported in the English medical literature. Patient concerns: A 46-year-old man complained of left shoulder weakness and limited movement ongoing for 1 month. He was primarily diagnosed with shoulder subluxation and rotator cuff tear based on magnetic resonance imaging, and was advised to undergo arthroscopic rotator cuff surgical repair. Diagnoses: Although rotator cuff tear was diagnosed in another hospital, some doubts remained. First, a tendon profile with a relative high signal in T2-weighted magnetic resonance images in the supraspinatus tear area still existed. The findings were clearly different from the usual full-thickness rotator cuff tear, and no tendon profile could be found in the tear area. Second, degenerative rotator cuff tear mainly occurs in the aged population and this patient was relatively young, without a history of trauma. His left shoulder was painless but the weakness and the limited movement were extreme and all of these factors did not support the diagnosis of rotator cuff tear. Some infectious disease was suspected to be the cause and relevant laboratory tests were conducted. This patient was eventually diagnosed as having brucellosis-associated shoulder subluxation and rotator cuff tendinopathy based on positive serum standard tube agglutination test and buffer plate agglutination test for brucellosis. Interventions: Oral drug therapy with rifampicin and doxycycline was used for 8 weeks. Outcomes: A complete response with normal shoulder strength and movement was achieved at 8 weeks. At the one-year follow-up no signs of recurrence were detected. Lessons: Brucellosis-associated shoulder subluxation and rotator cuff tendinopathy may be misdiagnosed as a rotator cuff tear in magnetic resonance imaging and be further managed with indeterminate arthroscopic repair. A comprehensive understanding of the patient’s previous medical history, imaging and laboratory data and a careful physical examination are of great clinic value for the accurate diagnosis of the condition and the subsequent prognosis of the patient.

Evaluation of the metabolic activity of the torn rotator cuff muscles by 18 F-2-deoxy- d -glucose PET-computed tomography scan.

Fatty atrophy and fatty infiltration have been considered as limiting factors for rotator cuff repair. The metabolic activity of the muscle can be measured noninvasively by PET. In our study, we aim to compare the metabolic activity between the shoulders with rotator cuff tears and normal shoulders. All the patients with unilateral full-thickness rotator cuff tears were included. The patients were divided into two groups based on fatty atrophy and the metabolic activities of the rotator cuff muscles, trapezius, and deltoid were calculated using an 18 F-2-deoxy- d -glucose PET-computed tomography scan for comparison. A total of 17 patients were included. The standardized uptake values were compared between the affected shoulder and the normal shoulders. There was a significant increase in uptake in the insertion sites and musculotendinous junctions in the rotator cuff torn group. The standardized uptake values showed no significant difference between the low-grade and high-grade groups. Our first hypothesis was also proven wrong; when we found that there was no statistically significant difference in the metabolic activity in muscle bellies of normal shoulders and those with rotator cuff tears. Our second hypothesis was proven wrong when found that there was no statistically significant difference in the metabolic activities of rotator cuff muscles between high-grade and low-grade fatty atrophy groups. The metabolic activities of the middle deltoid and trapezius are inversely related. Based on the findings of our study, fatty atrophy or fatty infiltration alone cannot be considered a limiting factor for rotator cuff repair.

Shoulder Bone Segmentation with DeepLab and U-Net.

Evaluation of 3D bone morphology of the glenohumeral joint is necessary for pre-surgical planning. Zero echo time (ZTE) magnetic resonance imaging (MRI) provides excellent bone contrast and can potentially be used in place of computed tomography. Segmentation of shoulder anatomy, particularly humeral head and acetabulum, is needed for detailed assessment of each anatomy and for pre-surgical preparation. In this study we compared performance of two popular deep learning models based on Google's DeepLab and U-Net to perform automated segmentation on ZTE MRI of human shoulders. Axial ZTE images of normal shoulders (n=31) acquired at 3-Tesla were annotated for training with a DeepLab and 2D U-Net, and the trained model was validated with testing data (n=13). While both models showed visually satisfactory results for segmenting the humeral bone, U-Net slightly over-estimated while DeepLab under-estimated the segmented area compared to the ground truth. Testing accuracy quantified by Dice score was significantly higher (p<0.05) for U-Net (88%) than DeepLab (81%) for the humeral segmentation. We have also implemented the U-Net model onto an MRI console for a push-button DL segmentation processing. Although this is an early work with limitations, our approach has the potential to improve shoulder MR evaluation hindered by manual post-processing and may provide clinical benefit for quickly visualizing bones of the glenohumeral joint.

Intraoperative Spinal Accessory Nerve Monitoring During Neck Dissection Surgery as a Predictor for Shoulder Dysfunction.

Shoulder dysfunction is one of the most common complications seen in patients who have undergone neck dissection surgery. The prevalence of shoulder dysfunction increases depending on the type and extent of neck dissection surgery. We aim to study the relationship between changes in intraoperative neuromonitoring (IONM) threshold during SAN stimulation, ultrasonographic measurement of muscle size and shear wave elastography with shoulder dysfunction. This is a prospective study. All patients who have undergone neck dissection in our centre have been recruited. Analysis of demographic data, IONM threshold during exposure and pre-closure, shoulder function score, neck disability index score (NDII) and ultrasonographic parameters pre-op and during follow up was done. The cohort was divided into patients who suffered from shoulder dysfunction post op (Group A) and patients with normal shoulder function post op (Group B). Statistical significance were seen in IONM threshold during SAN stimulation and Constant shoulder score for 6 months follow up in Group A. IONM threshold difference during exposure and pre-closure could effectively prognosticate shoulder dysfunction post op. A return of shoulder function could be seen in patients who suffered from shoulder dysfunction if early physiotherapy could be commenced.

The Buford Complex Redefined: A Pathologic Morphology in Sheep's Clothing.

Considered a normal anatomic variant, the Buford complex has not been studied in children. A Buford complex is not a normal anatomic variant and would, therefore, be present at a lower rate than that seen in the adult population. Cross-sectional study; Level of evidence, 3. Measurements were recorded from magnetic resonance imaging performed over 13 years in children aged ≤11 years for various pathologies unrelated to glenohumeral instability. Interrater reliability was determined to identify Buford complexes, sublabral foramens and tears, and normal shoulders via 16 preadolescent and adolescent patients with confirmed arthroscopic correlation. The Buford complex and labral foramen rates were then compared with a published rate in adults using a binomial probability test. A total of 122 children (62 girls; mean age, 6.4 years [age range, 2 months-10.9 years]) were evaluated. Interrater reliability was 0.846 (95% CI, 0.56-1) to identify anterosuperior labral variants. The expected sublabral foramen count was 23 children, but only 1 was identified (P < .001). The expected Buford complex count was 8 children, but none could be identified (P < .001). The absence of Buford complexes and the significant reduction in sublabral foramen abundance in younger children suggest that these anatomic variants are more likely to be developmental than congenital. The distinct possibility that these previously considered normal variants are truly pathologic findings cannot be ignored. Evidence of a Buford complex could potentially signify an underlying, long-term shoulder instability issue to the treating provider that warrants further investigation or management.

The Use of Linear Formulas to Estimate Glenoid Bone Loss in the Lebanese Population: A 3-Dimensional Computed Tomography Study.

Glenoid bone loss (GBL) is common in patients with shoulder instability and plays a major role in surgical decision-making. While a plethora of GBL estimation methods exist, all of which present specific challenges, recent studies have developed simple linear formulas estimating GBL based on glenoid height. To assess the correlation between glenoid height and width, and to develop specific formulas based on age and sex to calculate the native glenoid width in the Lebanese population. Cross-sectional study; Level of evidence, 3. Computed tomography scans for 202 normal shoulders were extracted from our database. The glenoids were reconstructed in 3 dimensions and their width and height were measured. Glenoid width and height were compared between male and female groups. Correlation analysis was also performed on the width, height, age, and body mass index. Formulas estimating glenoid width were developed using regression analysis including all variables significantly influencing the model. Results were then compared with the values calculated using previously published formulas to determine the external validity when using linear formulas to estimate GBL. Significant differences were found between men and women. Regression analysis found that glenoid height and width strongly influenced the model, and that age showed a weak but significant correlation; therefore, the following 2 sex-specific formulas were developed: width (mm) = 6.1 + 0.51 ×height+ 0.03 ×age, and width (mm) = 4.55 + 0.51 ×height+ 0.03 ×age, in men and women, respectively. The values yielded from the formulas developed in this study and the true width significantly differed from those calculated from previous reports. A strong correlation was found between glenoid height and width in a the Lebanese population and demonstrated that glenoid width can be accurately calculated based on the glenoid height and patient's age and sex using the following simplified formulas: width (mm) = 6 + 0.5 ×height+ 0.03 ×age, and width (mm) = 4.5 + 0.5 ×height+ 0.03 ×age, in men and women, respectively.

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.

Arthroscopic lasso-loop technique for subscapularis repair with anterolateral viewing portal yields better clinical outcomes for Lafosse grade 3 and 4 tears: a prospective study with minimum 2 years of follow-up

BackgroundContracted subscapularis tears, especially Lafosse grade 3 and 4, pose a significant challenge in surgical repair due to the need for extensive release of retracted tendon and the risk of cut-through due to poor tissue quality. The posterior viewing portal may hinder adequate visualization and extensive release of retracted tendons, particularly in addressing the bursal surface of the tears. Tension-free robust repair is critical to prevent retears and for achieving successful outcomes for these massive and complex retracted tears. This study investigates the clinical outcomes of the Lasso-Loop technique with an anterolateral viewing portal, aiming to enhance tendon release, improve footprint fixation, and optimize tissue grip, particularly in cases of chronic retracted Lafosse 3 and 4 tears. This innovation also eliminates the need for arthroscope switching and serves as a crucial measure for averting axillary nerve injuries during the procedure. MethodsThe study included 40 patients with isolated subscapularis or combined anterosuperior rotator cuff tears ( Lafosse grade 3 and 4) who underwent arthroscopic subscapularis repair using a Lasso-Loop technique through an anterolateral viewing portal. Evaluations were conducted both preoperatively and at predefined postoperative intervals: 6 weeks, 3 months, 6 months, 1 year, and 2 years. The evaluations in this study encompassed a comprehensive range of clinical assessments, which included a complete range of movements, specialized tests for subscapularis muscle functionality (specifically the Lift off test and Belly press test), the utilization of the UCLA and Oxford Shoulder scoring systems, and a postoperative ultrasonography conducted at the 6-month mark to assess the presence of any retear. Clinical outcomes were compared with that of the opposite normal shoulder. ResultsThere was considerable improvement in the active painless range of motion postoperatively. During the 2-year follow-up, the positive belly press test decreased from 50% (n=20) to 2.5% (n=1), while the positive lift-off test decreased from 100% (n=40) to 5% (n=2). The mUCLA score increased significantly from 10.15 preoperatively to 30.17 at 2 years postoperatively (P Value = 0.001). Oxford’s shoulder score increased significantly from 15.6 preoperatively to 40.64 at 2 years postoperatively (P Value = 0.001). ConclusionThis technique has produced positive functional outcomes, in cases categorized as massive subscapularis tears and chronic tears indicating the superiority over other conventional techniques of subscapularis repair described in the literature.

A novel return-to-play battery for shoulder injury/surgery: Normative values and psychometric properties

Objective: The Singapore Institute of Technology Shoulder Assessment Battery (SIT-SAB) is a novel shoulder test battery involving six different tests. It is created to aid clinicians in the return-to-play decision-making process. This study aims to establish the normative score for the SIT-SAB and assess the reliability of its scoring criteria. Methods: This cross-sectional observational study looked at healthy adults aged 18 or older with asymptomatic shoulders and normal shoulder mobility were recruited for the study. The participants performed all the tests in the SIT-SAB, and the measurements and scores obtained were recorded. Nineteen participants returned for two additional sessions on separate days to analyse the SIT-SAB's reliability. The inter-rater, intra-rater and test–retest reliability was calculated using a two-way mixed effect International Consensus Criteria (ICC) model. The ICC coefficient and the 95% confidence interval were used to determine the reliability of the SIT-SAB. Results: The SIT-SAB demonstrated good inter-rater, intra-rater and inter-day reliability (ICC = 0.81 (0.51–0.93), 0.97 (0.92–0.99), 0.89 (0.78–0.96), respectively) and has a mean score of 87.3 ± 10.3. The SIT-SAB scores were not correlated with any demographic, anthropometric characteristics or other factors. Conclusion: The findings provided the normative score to be expected of a healthy Singaporean adult and showed that the scoring criteria used were stable and demonstrated good reliability. Further research is needed to establish the cut-off score required for a safe return-to-play.

In Vivo 3-Dimensional Dynamic Evaluation of Shoulder Kinematics After the Latarjet Procedure: Comparison With the Contralateral Healthy Shoulder.

Researchers have attempted to understand the underlying mechanism of the Latarjet procedure; however, its effects on shoulder kinematics have not been well studied. The purpose was to analyze shoulder kinematics after the Latarjet procedure. It was hypothesized that the nonanatomic transfer of the coracoid process during the procedure would affect normal shoulder kinematics. Controlled laboratory study. The study included 10 patients (age range, 20-52 years) who underwent the modified Latarjet procedure between June 2016 and November 2021. Computed tomography and fluoroscopy were conducted on both shoulder joints of all patients, and 3-dimensional models were reconstructed. The 3-dimensional coordinates were encoded on the reconstructed models, and shoulder kinematics were analyzed through a 3-dimensional-2-dimensional model-image registration technique. Scapular rotation parameters (scapular upward rotation, posterior tilt, external rotation, and scapulohumeral rhythm) were compared between the Latarjet and the nonsurgical contralateral sides during humeral abduction, as was anteroposterior (AP) translation relative to the glenoid center during active humeral external rotation. The Latarjet side displayed significantly higher values of scapular upward rotation at higher degrees of humeral elevation (130°, 140°, and 150°) compared with the nonsurgical side (P = .027). Posterior tilt, external rotation, and scapulohumeral rhythm were not significantly different between sides. AP translation at maximal humeral rotation was not significantly different between sides (Latarjet, -0.06 ± 5.73 mm vs nonsurgical, 5.33 ± 1.60 mm; P = .28). Interestingly, on the Latarjet side, AP translation increased until 40° of humeral rotation (4.27 ± 4.64 mm) but began to decrease from 50° of humeral rotation. The Latarjet side demonstrated significant changes in scapular upward rotation during higher degrees of humeral elevation compared with the contralateral shoulder. Posterior movement of the humeral head at >50° of humeral rotation could be the desired effect of anterior stabilization; however, researchers should evaluate long-term complications such as osteoarthritis. Analysis of shoulder kinematics after the Latarjet procedure could provide information regarding long-term outcomes and whether the procedure would affect the daily activities of patients.

Shoulder Arthroplasty After Previous Nonarthroplasty Surgery: A Systematic Review and Meta-Analysis of Clinical Outcomes and Complications.

Many patients who undergo shoulder arthroplasty (SA) have had at least 1 nonarthroplasty shoulder surgery before the surgery. There is conflicting evidence regarding the effects of previous shoulder surgery on the outcome of SA. A systematic review was conducted to compare functional outcomes and complications between SA patients with and without prior non-SA surgery on the ipsilateral shoulder. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searched MEDLINE/PubMed, Embase, Scopus, and Web of Science comprehensively from inception to January 2023. Based on 9,279 records reviewed, 26 comparative studies were included in the meta-analysis consisting of 5,431 shoulders with prior nonarthroplasty procedures (cases) and 55,144 shoulders without previous surgery (controls). Variables such as functional scores, complications, and range of motion were compared between cases and controls using Review Manager Software. In addition, subgroup analysis was conducted based on prior surgery type (rotator cuff repair [RCR], open reduction and internal fixation [ORIF], soft tissue repairs, and not specified) and type of SA (hemiarthroplasty, anatomical total shoulder arthroplasty, and reverse total shoulder arthroplasty [RTSA]). The results were presented as odds ratios (ORs) or standardized mean differences (SMDs). Except for a higher rate of periprosthetic joint infection (PJI) in patients who had undergone previous arthroscopic surgery (OR, 2.58; 95% confidence interval [CI], 1.66-4.01; p < 0.01), a higher rate of complications was only observed in patients with previous ORIF. These complications included aseptic loosening (OR, 3.43; 95% CI, 2.14-5.50; p < 0.01), shoulder dislocation (OR, 2.25; 95% CI, 1.05-4.84; p = 0.04), overall complication (OR, 3.95; 95% CI, 2.38-6.55; p < 0.01), and revision (OR, 2.52; 95% CI, 1.28-4.97; p = 0.01). Patients with a history of previous surgery demonstrated inferior functional outcomes in comparison with the control group, including American Shoulder and Elbow Surgeons (SMD, -0.39; 95% CI, -0.51 to -0.27; p < 0.01; I2 = 36%), Constant-Murley score (SMD, -0.34; 95% CI, -0.44 to -0.24; p < 0.01; I2 = 0%), abduction (SMD, -0.26; 95% CI, -0.45 to -0.08; p = 0.01; I2 = 54%), and flexion (SMD, -0.33; 95% CI, -0.46 to -0.21; p < 0.01; I2 = 40%). Subgroup analysis by previous type of surgery was not possible regarding functional outcomes. Patients who have had prior fracture surgery are at a higher risk of complications, reoperations, and revisions after SA than controls. The normal shoulder anatomy may be disrupted by prior surgery, which makes arthroplasty technically challenging, particularly when it comes to soft tissue balance. On the other hand, RCR before SA did not negatively affect clinical outcomes after RTSA and did not have a higher rate of overall complications (except PJI). Level III (Treatment Studies). See Instructions for Authors for a complete description of levels of evidence.

Residual kinematic deviations of the shoulder during humeral elevation after conservative treatment for mid-shaft clavicle fractures.

Despite residual functional deficits clinically observed in conservatively treated mid-shaft clavicle fractures, no study has reported a quantitative assessment of the treatment effects on the kinematics of the shoulder complex during functional movement. Using computerised motion analysis, the current study quantified the 3D residual kinematic deviations or strategies of the shoulder complex bones during multi-plane elevations in fifteen patients with conservatively treated mid-shaft clavicle fractures and fifteen healthy controls. Despite residual clavicular malunion, the patients recovered normal shoulder kinematics for arm elevations up to 60° in all three tested planes. For elevations beyond 60°, normal clavicle kinematics but significantly increased scapular posterior tilt relative to the trunk was observed in the patient group, leading to significantly increased clavicular protraction and posterior tilt relative to the scapula (i.e., AC joint). Slightly different changes were found in the sagittal plane, showing additional changes of increased scapular upward rotations at 90° and 120° elevations. Similar kinematic changes were also found on the unaffected side, indicating a trend of symmetrical bilateral adaptation. The current results suggest that shoulder kinematics in multi-plane arm elevations should be monitored for any compromised integrated motions of the individual bones following conservative treatment. Rehabilitation strategies, including muscle strengthening and synergy stability training, should also consider compensatory kinematic changes on the unaffected side to improve the bilateral movement control of the shoulder complex during humeral elevation.

Biomechanical Evaluation of the 2 Different Levels of Coracoid Graft Positions in the Latarjet Procedure for Anterior Shoulder Instability.

In the Latarjet procedure, the ideal placement of the coracoid graft in the medial-lateral position is flush with the anterior glenoid rim. However, the ideal position of the graft in the superior-inferior position (sagittal plane) for restoring glenohumeral joint stability is still controversial. To compare coracoid graft clockface positions between the traditional 3 to 5 o'clock and a more inferior (for the right shoulder) 4 to 6 o'clock with regard to glenohumeral joint stability in the Latarjet procedure. Controlled laboratory study. A total of 10 fresh-frozen cadaveric shoulders were tested in a dynamic, custom-built robotic shoulder model. Each shoulder was loaded with a 50-N compressive load while an 80-N force was applied in the anteroinferior axes at 90° of abduction and 60° of shoulder external rotation. Four conditions were tested: (1) intact, (2) 6-mm glenoid bone loss (GBL), (3) Latarjet procedure fixed at 3- to 5-o'clock position, and (4) Latarjet procedure fixed at 4- to 6-o'clock position. The stability ratio (SR) and degree of lateral humeral displacement (LHD) were recorded. A 1-factor random-intercepts linear mixed-effects model and Tukey method were used for statistical analysis. Compared with the intact state (1.77 ± 0.11), the SR was significantly lower after creating a 6-mm GBL (1.14 ± 0.61, P = .009), with no significant difference in SR after Latarjet 3 to 5 o'clock (1.51 ± 0.70, P = .51) or 4 to 6 o'clock (1.55 ± 0.68, P = .52). Compared with the intact state (6.48 ± 2.24 mm), LHD decreased significantly after GBL (3.16 ± 1.56 mm, P < .001) and Latarjet 4 to 6 o'clock (5.48 ± 3.39 mm, P < .001). Displacement decreased significantly after Latarjet 3 to 5 o'clock (4.78 ± 2.50 mm, P = .04) compared with the intact state but not after Latarjet 4 to 6 o'clock (P = .71). The Latarjet procedure in both coracoid graft positions (3-5 and 4-6 o'clock) restored the SR to the values measured in the intact state. A more inferior graft position (fixed at 4-6 o'clock) may improve shoulder biomechanics, but additional work is needed to establish clinical relevance. An inferior coracoid graft fixation, the 4- to 6-o'clock position, may benefit in restoring normal shoulder biomechanics after the Latarjet procedure.

The effects of stance width during barbell hip thrust on power and velocity output among adolescent Silat athletes

Background and Study Aim. In the physically demanding combat sport of Silat, strength and power dominate. Consequently, applying various stance widths during barbell hip thrusts may tailor athletes' lower-body exercises to individual needs. This has the potential to optimize performance. The aim of this study is to investigate the impact on performance of power, speed, and stance width among Silat combat athletes. Material and Methods. Participants performed 10RM tests in three stance widths: wider than shoulder width (WSW), normal shoulder width (NSW), and narrower than shoulder width (NRW). This was done using a 72-hour counterbalance cross-over study design. Power and velocity were measured and analyzed using a mixed ANOVA design. Results. The results indicated a significant main effect of stance width on power (F(2,56) = 3.086, p &lt; 0.05) and velocity (F(2,56) = 3.683, p &lt; 0.03) output. Both males and females demonstrated the highest power in NRW (M = 413.26, SD = 131.76; M = 239.53, SD = 111.16), followed by WSW and NSW. A strong positive correlation between power and velocity was observed for all stance widths: WSW (r(28) = 0.77, p &lt; 0.001), NSW (r(28) = 0.79, p &lt; 0.001), and NRW (r(28) = 0.89, p &lt; 0.001). NRW was associated with superior power production, while WSW facilitated higher velocity. Conclusion. The results of this study demonstrate the importance of considering a variety of stance width techniques during exercise due to their effects on power and velocity during the barbell hip thrust exercise. Coaches can tailor training programs with a velocity-targeted strength and conditioning approach to enhance performance and competitiveness. Further research should investigate different athlete groups and age levels to refine training methodologies.

Magnetic Resonance Imaging of the Shoulder: Interpretation of Common Orthopaedic Injuries.

Magnetic resonance imaging (MRI) is frequently obtained to assess for pathology in the setting of shoulder pain and dysfunction. MRI of the shoulder provides diagnostic information that helps optimize patient management and surgical planning. Both general and subspecialized orthopaedic surgeons routinely order and review shoulder MRIs in practice. Therefore, familiarity with the MRI appearance of common shoulder pathologies is important. This document reviews the most common shoulder pathologies using a standardized MRI interpretative approach. Instructional videos demonstrating a musculoskeletal radiologist interpreting normal and abnormal shoulder MRIs are also provided.