Systematic Review of Shoulder Imaging Abnormalities in Asymptomatic Adult Shoulders (SCRUTINY): Abnormalities of the glenohumeral joint.

OBJECTIVE: The primary objective was to determine the population prevalence of glenohumeral joint imaging abnormalities in asymptomatic adults. METHOD: We systematically reviewed studies reporting the prevalence of X-ray, ultrasound (US), computed tomography, and magnetic resonance imaging (MRI) abnormalities in adults without shoulder symptoms (PROSPERO registration number CRD42018090041). This report presents the glenohumeral joint imaging findings. We searched Ovid MEDLINE, Embase, CINAHL and Web of Science from inception to June 2023 and assessed risk of bias using a tool designed for prevalence studies. The primary analysis was planned for the general population. The certainty of evidence was assessed using a modified Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) for prognostic studies. RESULTS: Thirty-five studies (4 X-ray, 10 US, 20 MRI, 1 X-ray and MRI) reported useable prevalence data. Two studies were population-based (846 shoulders), 15 studies included miscellaneous study populations (1715 shoulders) and 18 included athletes (727 shoulders). All were judged to be at high risk of bias. Clinical diversity precluded pooling. Population prevalence of glenohumeral osteoarthritis ranged from 15% to 75% (2 studies, 846 shoulders, 1 X-ray, 1 X-ray and MRI; low certainty evidence). Prevalence of labral abnormalities, humeral head cysts and long head of biceps tendon abnormalities were 20%, 5%, 30% respectively (1 study, 20 shoulders, X-ray and MRI; very low certainty evidence). CONCLUSION: The population-based prevalence of glenohumeral joint imaging abnormalities in asymptomatic individuals remains uncertain, but may range between 30% and 75%. Better estimates are needed to inform best evidence-based management of people with shoulder pain.

The comparative effectiveness of combined hydrodilatation/corticosteroid procedure with two different quantities for adhesive capsulitis.

OBJECTIVE: To assess the efficacy of injecting various amounts of fluid into the shoulder joints for capsule distension in patients with adhesive capsulitis. DESIGN: A randomized controlled trial. SETTING: Outpatient clinic of a tertiary care centre. PARTICIPANTS: Eighty-four patients with adhesive capsulitis underwent a baseline (time0), 6 weeks (time1), and 12 weeks (time2) follow-up after hydrodilitation. INTERVENTION: Group 1 (n = 42) received 20 ml of lidocaine, steroid, and saline hydrodilatation via posterior glenohumeral recess, while Group 2 (n = 42) received 10 ml of lidocaine, steroid, and saline hydrodilitation. MAIN MEASURES: The primary outcome was the visual analogue scale for pain. The secondary outcomes were shoulder pain and disability index (SPADI) and ROM of the shoulder. RESULTS: There was a significant reduce in VAS scores for pain, SPADI scores, and increased shoulder ROM in both groups over time; however, the group-by-time interactions for any of the outcomes between groups were not significant except VAS pain in motion. Post-hoc pairwise analysis of the marginal effect of time and group showed that the significant difference of VAS in motion is due to time effect: time1 vs time0 (95% CI -4.09 to -2.68), time2 vs time0 (-4.21 to -2.77), and time2 vs time1 (-0.83 to 0.63), without between-group difference: group 1 vs group 2 (-0.38 to 0.59). CONCLUSION: Our study suggests hydrodilatation achieved an optimal effect at time1 for patients with adhesive capsulitis in both groups, and adding more saline offers additional benefits in flexion and external roatation until time2.

Posterolateral dislocation and incarceration of the long head of the biceps tendon: a rare cause of irreducible anterior glenohumeral joint dislocation-a case report and brief review of the literature.

Failure of closed reduction of anterior glenohumeral joint dislocation is infrequent. It can be secondary to osseous (e.g., fracture fragments or Hill-Sachs lesion) or soft tissue (e.g., labrum or rotator cuff tendon) impediments. Herein, we present a case of a prolonged irreducible glenohumeral joint secondary to a posterolaterally dislocated and incarcerated long head of the biceps tendon after an episode of anterior instability, highlight the utility of MR imaging for guiding management, and review the literature of this sporadic diagnosis.

Changes in Shoulder Rotation Based on Elevation in Children With Brachial Plexus Birth Injury.

PURPOSE: Lack of shoulder external rotation is common in children with brachial plexus birth injuries. Development of glenohumeral (GH) dysplasia is associated with progressive loss of passive external rotation. Some authors recommend measuring external rotation with the arm adducted, whereas others recommend measurement with the arm in 90° of abduction. The purpose of this study was to compare active and passive external rotation and internal rotation measured in adduction versus abduction. METHODS: Fifteen children with brachial plexus birth injuries held their affected arms in maximal external and internal rotation with the arm adducted and the arm at approximately 90° of abduction. Active and passive rotations were measured with three-dimensional motion capture. Scapulothoracic (ST) internal/external rotation and GH internal/external rotation joint angles were calculated and compared using multivariable, one-way repeated measures analyses of variance. RESULTS: There were no significant differences for active or passive ST rotation in external rotation in adduction versus abduction. Glenohumeral external rotation was significantly increased with the arm in abduction compared with adduction both actively and passively. There were no differences in ST rotation in active versus passive conditions, but all GH rotations were significantly greater passively. CONCLUSIONS: Shoulder internal/external rotation in abduction and adduction is not interchangeable. Comprehensive assessment of shoulder external and internal rotation should include both adduction and abduction. CLINICAL RELEVANCE: For children with brachial plexus birth injuries, both active and passive GH external rotations were greater in abduction. Therefore, early GH joint dysplasia may be missed if GH external rotation is measured in abduction. Additionally, consistency in arm position is important for comparison over time. The entire ST rotation capacity was used to perform maximal internal and external rotation, but the entire passive GH range of motion was not actively used. This highlights an area for potential surgical intervention to improve motion.

Glenohumeral arthrodesis outcomes and complications: a systematic review.

BACKGROUND: The purpose of this study was to systematically review the evidence in the literature to determine the clinical outcomes following glenohumeral arthrodesis. METHODS: Two independent reviewers performed a literature search in the PubMed database based on Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Studies were included if they reported on outcomes following shoulder arthrodesis from the years of 2000-2022. Functional outcomes that were collected included the Subjective Shoulder Value, American Shoulder and Elbow Surgeons shoulder index score, visual analog scale pain score, and Oxford Shoulder Score. Range-of-motion data were also collected. RESULTS: This review included 17 studies, with a total of 316 patients, that met the inclusion criteria. The majority of the patients were male (67.4%), and the average age was 38.4 years (range, 7-82 years). The overall fusion rate was 88.7%, and the time to fusion was on average, 3.9 months (range, 2-8 months). Shoulder arthrodesis resulted in improvement in each of the functional outcomes assessed: Subjective Shoulder Value (preoperatively, 18.8; postoperatively, 43.9; and percent change, 132.8%), American Shoulder and Elbow Surgeons shoulder index score (postoperatively, 62.1), visual analog scale pain score (preoperatively, 8.5; postoperatively, 3.03; and percent change, 62.4%), and Oxford Shoulder Score (preoperatively, 9.4; postoperatively, 30.9; and percent change, 328.7%). The abduction, forward flexion, external rotation, and internal rotation range-of-motion measurements postoperatively were 57°, 64°, 3°, and 48°, respectively. Complications were reported in 33.6% of patients, with fractures (20.9%) and infections (18.6%) being the most common sources of complication. CONCLUSION: Shoulder arthrodesis provides improvement in functional outcomes for end-stage glenohumeral injuries; however, it is also associated with high rates of complications.

Shoulder external rotation contracture following neonatal brachial plexus injury.

BACKGROUND: Glenohumeral posterior external rotation contractures and scapular winging are frequently overlooked problems in residual neonatal brachial plexus injury (NBPI). Recent attention has emphasized their impact on vital functions such as feeding and hygiene. This study aims to present the epidemiology of posterior glenohumeral contractures in a significant pediatric NBPI population and explore contributing factors. METHODS: We conducted a retrospective analysis of data collected from January 2019 to November 2022, involving a case series of 262 children with residual NBPI. The data included demographics, palsy level, prior surgical history, and the modified Mallet scale. Glenohumeral passive internal rotation in abduction and cross-body adduction angles were measured bilaterally. Subjects were categorized into "Belly-" (Mallet hand-to-belly <3) and "Belly+" (Mallet hand-to-belly ≥3) groups. RESULTS: The median participant age was 7.9 years (range: 3.5-21 years). Extension injury patterns included Erb's palsy (56.5%), extended Erb's palsy (28.6%), and global palsy (14.9%). Contractures exceeding 10°, 20°, and 30° were prevalent in both internal rotation in abduction and cross-body adduction angles. The "Belly-" group (9.5%) demonstrated a significant reduction in both angles compared to the "Belly+" group. Weak correlations were found between internal rotation in abduction (r = 0.390, P < .0001) or cross-body adduction (r = 0.163, P = .0083) angles and Mallet hand-to-abdomen item. Glenohumeral reduction and Hoffer procedures led to a notable decrease in cross-body adduction angle, without affecting "Belly-" prevalence. Global injuries exhibited decreased angles compared to Erb's group. CONCLUSIONS: External rotation glenohumeral contractures are prevalent in residual NBPI, impacting midline access. Surprisingly, the history of glenohumeral procedures or extensive injuries did not increase the likelihood of losing the ability to reach the belly. Receiver operating characteristic analysis suggests specific thresholds for maintaining this ability.

Long Head of the Biceps Tendon Plays a Role in Stress Absorption and Humeral Head Restriction during the Late Cocking and Deceleration Phases of Overhead Throwing: A Finite Element Study.

BACKGROUND: Emerging evidence suggests that the long head of the biceps (LHBT) may play a role in stabilizing the glenohumeral joint, and this has led to controversy around the efficacy of biceps tenotomy for superior labral anterior and posterior (SLAP) lesions. Therefore, the aim of this finite element analysis (FEA) study was to determine the stress absorption and humeral head translation restriction effects of the LHBT within the glenohumeral joint during the late cocking and deceleration phases of overhead throwing with a view to resolving the controversy around tenotomy. METHODS: Eight FEA models were created using computed tomography and magnetic resonance imaging data from normal glenohumeral joints. The models represented four LHBT conditions: uninjured, subpectoral tenodesis, tenotomy, and type II SLAP lesions. The late cocking and deceleration phases of the overhead throwing were simulated for each model. The impacts of the four LHBT conditions on glenohumeral joint stress absorption and humeral head displacement restriction were studied based on 1) stress and related distributions on the cartilage, labrum, capsule, and LHBT and 2) humeral head translation variation. RESULTS: The FEA analysis showed that the magnitude of the contact stress on the articular cartilage, labrum, and capsule was the lowest in the uninjured models, followed by the subpectoral tenodesis, tenotomy, and type II SLAP lesion models. Humeral head translation was the most restricted in the subpectoral tenodesis models, followed by the tenotomy and type II SLAP lesion models. CONCLUSION: Finite element analysis demonstrated that the LHBT plays a significant role in stress absorption and displacement restriction in the late cocking and deceleration phases of overhead throwing. Subpectoral tenodesis of the LHBT exhibited lesser amount of stress and humeral head translation than those of tenotomy, thereby making it a better option for patients who engage in overhead throwing.

Maximum in-vivo joint contact forces double during active compared to assisted motion in the glenohumeral joint and decline long-term due to rotator cuff pathologies.

Rehabilitation programs advocate early passive and assisted motion after rotator cuff repair to induce healing und maintaining range of motion while avoiding excessive strain on the repaired tendons. In-vivo glenohumeral joint contact forces reflect the compressive forces generated by the rotator muscles. In the present study, maximum in-vivo joint contact forces (FresMax) were determined to compare active and assisted execution of a single movement and the long-term development of joint compression forces. FresMax were measured in six patients who received instrumented, telemetric modified anatomical hemi endoprostheses of the shoulder joint between 2006 and 2008. Data were gathered 23 months postoperatively (2006-2010), were analysed and compared with measurements 133 months postoperatively. Additional imaging was obtained as x-rays and ultrasound examination. Data analysis was conducted by synchronizing video tapes and measured force curves. New imaging showed a rupture of the M. supraspinatus and progressive joint degeneration. FresMax nearly doubled during active compared to assisted execution of each of the four chosen movements. Over the course of 133 months post-surgery, the studied movements showed a decrease of active compression force, probably due to a ruptured supraspinatus, resulting in a lower active/assisted ratio. A long term follow up after eleven years, eight out of ten measured movements showed a decrease of FresMax. These results support current rehabilitation protocols recommending early passive and assisted motion to limit activation of the rotator muscles generating compressive forces. Following degeneration of the rotator cuff, active joint contact forces decrease over time.Level of evidence: III.

Growth of the brachial nerve plexus with reference to topographical relation of the medianus nerve ansa with the thoracic wall and shoulder: a histologic study using human embryos and fetuses.

BACKGROUND: There is currently no information on positional changes in the brachial nerve plexus during prenatal growth. The subclavian-axillary artery passing through the medianus nerve ansa is considered a good landmark for evaluating the height of the plexus. MATERIALS AND METHODS: We used histologic sections from 9 embryos and 17 fetuses (approximately 6-15 weeks of gestational age) to identify the height of the ansa by referring to the level of the rib and the glenohumeral joint. RESULTS: The nerve ansa was usually (23 plexuses) observed at the level of the first and/or second ribs. However, it was sometimes observed above the first rib, at a distance equal to or more than an intercostal width (7 plexuses). In the latter group, the ansa was usually located below the glenohumeral joint. Thus, the joint was located higher than the first rib, although the upper extremities were in the anatomic position for all specimens. The left-right difference in the height of the plexus corresponded to or was less than the width of the first intercostal space. Despite the synchronized growth between the thorax and shoulder girdle, the brachial plexus showed a considerable variation in comparative height; the range corresponded to twice of an intercostal width. Whether the nerve plexus is located high or low is determined at an early developmental stage and is maintained during the later growth stages. CONCLUSION: The high-positioned plexus might cause nerve injury at delivery, followed by a glenohumeral joint deformity because of the fragility without fixation in the thorax.

Creating an Inexpensive PVC Shoulder Model for the Training of Ultrasound-Guided Posterior Glenohumeral Joint Injections.

OBJECTIVES: Ultrasound-guided injections are used to treat common shoulder pathologies and have been shown to be more accurate and effective than traditional landmark-guided procedures. Currently, there exists no inexpensive shoulder model that accurately simulates the anatomical structures of the shoulder while also facilitating glenohumeral joint (GHJ) injection. Our model is an alternative to the traditional bedside training and provides a low-risk training environment. METHODS: We created this model from easily accessible materials. Polyvinyl chloride pipe was used to create the skeletal infrastructure pectoral girdle. A detergent pod was used to represent the GHJ space. Steaks were used to simulate the infraspinatus and deltoid muscles, with meat glue as a fascial layer between the two simulated muscles. Total cost of materials for the model was $19.71. RESULTS: Our model successfully replicates known anatomical features of the GHJ. Additionally, the model facilitates injection into a GHJ space, representing a GHJ injection. Our model was replicated to train medical student practitioners during five different educational sessions. The model was validated through comparison to standardized educational ultrasound training videos. It was further validated by ultrasound experts. CONCLUSIONS: The shoulder model we created is effective in simulating GHJ injections under ultrasound guidance. It simulates realistic muscle and bony landmarks both for ultrasound imaging and injection feel. Importantly, it is inexpensive and easy to replicate allowing more access to medical practitioners and students to be educated on the procedure.

Effect of intraarticular pressure on glenohumeral kinematics during a simulated abduction motion: a cadaveric study.

BACKGROUND: The current understanding of glenohumeral joint stability is defined by active restrictions and passive stabilizers including naturally-occurring negative intraarticular pressure. Cadaveric specimens have been used to evaluate the role of intraarticular pressure on joint stability, although, while the shoulder's negative intraarticular pressure is universally acknowledged, it has been inconsistently accounted for. HYPOTHESIS: During continuous, passive humeral abduction, releasing the native intraarticular pressure increases joint translation, and restoring this pressure decreases joint translations. STUDY DESIGN: Descriptive Laboratory Study. METHODS: A validated shoulder testing system was used to passively abduct the humerus in the scapular plane and measure joint translations for seven (n = 7) cadaveric specimens. The pressure within the glenohumeral joint was measured via a 25-gauge needle during passive abduction of the arm, which was released and subsequently restored. During motion, the rotator cuff muscles were loaded using stepper motors in a force feedback loop and electromagnetic sensors were used to continuously measure the position of the humerus and scapula. Joint translation was defined according to the instant center of rotation of the glenohumeral head according to the recommendations by the International Society of Biomechanics. RESULTS: Area under the translation versus abduction angle curve suggests that releasing the pressure within the capsule results in significantly less posterior translation of the glenohumeral head as compared to intact (85-90˚, p < 0.05). Posterior and superior translations were reduced after 70˚ of abduction when the pressure within the joint was restored. CONCLUSION: With our testing system employing a smooth continuous passive motion, we were able to show that releasing intraarticular pressure does not have a major effect on the path of humeral head motion during glenohumeral abduction. However, both violating the capsule and restoring intraarticular pressure after releasing alter glenohumeral translations. Future studies should study the effect of simultaneous external rotation and abduction on the relationship between joint motion and IAP, especially in higher degrees of abduction. CLINICAL RELEVANCE: Thoroughly simulating the glenohumeral joint environment in the cadaveric setting may strengthen the conclusions that can be translated from this setting to the clinic.

Glenohumeral osteoarthritis: what the surgeon needs from the radiologist.

Glenohumeral osteoarthritis (GHOA) is a widely prevalent disease with increasing frequency due to population aging. Both clinical manifestations and radiography play key roles in the initial diagnosis, staging, and management decisions. Radiographic disease progression evaluation is performed using validated staging systems, such as Kellgren and Lawrence, Samilson, and Hamada. For young patients with mild to moderate GHOA and failed conservative treatment, arthroscopic preservation surgery (APS) is usually considered. Older patients and those with severe GHOA benefit from different types of arthroplasties. Preoperative magnetic resonance imaging (MRI) is essential for APS surgical planning, as it maps repairable labral, cartilage, and rotator cuff lesions. For arthroplasty planning, the status of glenoid cartilage and intactness of rotator cuff as well as glenoid morphology represent key factors guiding the decision regarding the most suitable hardware design, whether resurfacing, partial, total, or reverse joint replacement. Pre-surgical MRI or alternatively computed tomography arthrogram is employed to evaluate the cartilage and rotator cuff. Finally, three-dimensional computed tomography (3D CT) is indicated to optimally assess the glenoid morphology (to determine Walch classification, version, inclination, and bone loss) and analyze the necessity for glenoid osteotomy or graft augmentation to correct the glenoid structural abnormalities for future success and longevity of the shoulder implants or chosen constructs. Understanding the purpose of each imaging and treatment modality allows more efficient image interpretation. This article reviews the above concepts and details what a surgeon needs from a radiologist and could benefit from accurate reporting of preoperative imaging studies.

Ultrasound-guided interventions of the upper extremity joints.

Ultrasound guidance is valuable for performing precise joint interventions. Joint interventions may be requested for therapeutic and diagnostic pain injections, joint aspiration in the setting of suspected infection, or contrast injection for arthrography. In practice, interventions of the shoulder girdle, elbow, and hand/wrist joints may be performed without any imaging guidance. However, imaging guidance results in more accurate interventions and better patient outcomes than those performed by palpation alone. When compared to other modalities used for imaging guidance, ultrasound has many potential advantages. Radiologists should be prepared to perform ultrasound-guided upper extremity joint interventions utilizing recommended techniques to optimize clinical practice and patient outcomes. KEY POINTS: 1. Ultrasound-guided injections of the glenohumeral, acromioclavicular, sternoclavicular, elbow, and hand/wrist joints have higher accuracy than injections performed without imaging guidance. 2. Ultrasound-guided aspirations of upper extremity joints have advantages to fluoroscopic-guided aspirations because of the potential to identify effusions, soft tissue abscess, or bursitis. 3. Ultrasound-guided contrast injection prior to MR arthrography is as accurate as fluoroscopic-guided injection for upper extremity joints.

The evaluation, classification, and management of septic arthritis of the shoulder: the comprehensive shoulder sepsis system.

BACKGROUND: Septic arthritis of the shoulder is distinctly challenging to diagnose and treat. Guidelines for appropriate workup and management are limited and do not account for the variations in clinical presentation. The purpose of this study was to present a comprehensive and anatomically based classification system and treatment algorithm for septic arthritis of the native shoulder joint. METHODS: A multicenter, retrospective analysis of all patients treated surgically for septic arthritis of the native shoulder joint was performed at 2 tertiary care academic institutions. Preoperative magnetic resonance imaging and operative reports were used to classify patients as having 1 of 3 infection subtypes: type I, confined to the glenohumeral joint; type II, extra-articular extension; or type III, concomitant osteomyelitis. On the basis of these clinical groupings of patients, the comorbidities, types of surgical management, and outcomes were analyzed. RESULTS: Sixty-five shoulders in 64 patients met the inclusion criteria for the study. Of these infected shoulders, 9.2% had type I infections, 47.7% had type II, and 43.1% had type III. Age and the time between symptom onset and diagnosis were the only significant risk factors for the development of a more severe infection. Fifty-seven percent of shoulder aspirates revealed cell counts below the standard surgical cutoff of 50,000 cells/mL. On average, each patient required 2.2 surgical débridements to eradicate the infection. Infections recurred in 8 shoulders (12.3%). Body mass index was the only risk factor for recurrence of infection. Of the 64 patients, 1 (1.6%) died acutely of sepsis and multiorgan system failure. CONCLUSION: We propose a comprehensive system for the classification and management of spontaneous shoulder sepsis based on stage and anatomy. Preoperative magnetic resonance imaging can help determine the severity of disease and aid in surgical decision making. A systematic approach to septic arthritis of the shoulder as a unique entity from septic arthritis of other large peripheral joints may lead to more timely diagnosis and treatment and improve the overall prognosis.

Rotator cuff muscle degeneration in a mouse model of glenohumeral osteoarthritis induced by monoiodoacetic acid.

BACKGROUND: Osteoarthritis (OA) is a disease of joint degeneration and impaired function. Muscle atrophy, fatty infiltration, and fibrosis are degenerative features of muscle injury and predict poor outcomes in some degenerative and exercise-related injuries. Patients with glenohumeral joint OA usually have rotator cuff muscle degeneration, even though the rotator cuff is intact. However, the mechanism and correlation between OA and degeneration of muscles around joints are still unknown. METHODS: Forty-five 12-month-old C57BL/6J mice received a single injection of monoiodoacetic acid into the right glenohumeral joint. The sham group was injected with saline on the same day in the right glenohumeral joint. Three and 6 weeks after the operation, gait analysis was conducted to evaluate the function of the forelimb. Then, the shoulder joint and supraspinatus muscle were collected for histologic staining, reverse transcription quantitative polymerase chain reaction, and biomechanics test. Correlations between fat area fraction in muscle, percentage wet muscle weight change or Osteoarthritis Research Society International score, and gait analysis/muscle mechanics tests were assessed using Pearson's correlation coefficient or Spearman's correlation coefficient. RESULTS: Compared with the sham group, the monoiodoacetic acid group developed significant glenohumeral joint OA and the supraspinatus muscle developed significant fatty infiltration and muscle atrophy. Shoulder function correlated with glenohumeral joint OA/rotator cuff muscle severity, weight loss, and fatty infiltration. CONCLUSION: In mice, glenohumeral joint OA can lead to rotator cuff degeneration and inferior limb function. The small animal model could be a powerful tool to further study the potential mechanisms between glenohumeral OA and rotator cuff muscle degeneration.

Long-term outcomes after osteochondral allograft transplantation to the humeral head.

BACKGROUND: Long-term outcomes of osteochondral allograft (OCA) transplantation to the humeral head have been sparsely reported in the literature. PURPOSE: To evaluate outcomes and survivorship of OCA transplantation to the humeral head in patients with osteochondral defects at a minimum of 10 years of follow-up. METHODS: A registry of patients who underwent humeral head OCA transplantation between 2004 and 2012 was reviewed. Patients completed pre and postoperative surveys including the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, Short Form 12 (SF-12), and the visual analog scale. Failure was defined by conversion to shoulder arthroplasty. RESULTS: Fifteen of 21 (71%) patients with a minimum of ten year of follow-up (mean: 14.2 ± 2.40) were identified. Mean patient age was 26.1 ± 8.8 years at the time of transplantation and eight (53%) patients were male. Surgery was performed on the dominant shoulder in 11 of the 15 (73%) cases. The use of local anesthetic delivered via an intra-articular pain pump was the most often reported underlying etiology of chondral injury (n = 9; 60%). Eight (53%) patients were treated with an allograft plug, while seven (47%) patients were treated with a mushroom cap allograft. At final follow-up, mean American Shoulder and Elbow Surgeons (49.9 to 81.1; P = .048) and Simple Shoulder Test (43.1 to 83.3; P = .010) significantly improved compared to baseline. Changes in mean SF-12 physical (41.4 to 48.1; P = .354), SF-12 mental (57.5 to 51.8; P = .354), and visual analog scale (4.0 to 2.8; P = .618) did not reach statistical significance. Eight (53%) patients required conversion to shoulder arthroplasty at an average of 4.8 ± 4.7 years (range: 0.6-13.2). Kaplan-Meier graft survival probabilities were 60% at 10 years and 41% at 15 years. CONCLUSION: OCA transplantation to the humeral head can result in acceptable long-term function for patients with osteochondral defects. While patient-reported outcomes metrics were generally improved compared to baseline, OCA graft survival probabilities diminished with time. The findings from this study can be used to counsel future patients with significant glenohumeral cartilage injuries and set expectations about the potential for further surgery.

Electromyographic activities of glenohumeral joint muscles during shoulder forward flexion with isometric horizontal abduction loading.

BACKGROUND: Isometric horizontal abduction loading has been applied to improve imbalanced scapular muscle activities during shoulder exercises; however, the effect on glenohumeral joint muscle activity remains unclear. The purpose of this study was to investigate the changes in electromyographic activity of shoulder muscles during forward flexion with isometric horizontal abduction loading in healthy participants. METHODS: Thirteen healthy men were recruited for this study. Participants performed shoulder forward flexion with isometric horizontal abduction loading using an elastic band (Flex-band condition) and forward flexion without shoulder loading (Normal-flex condition). Muscle activities were evaluated while maintaining shoulder flexion at 60°, 90°, 120°, and 150° (static task) and during active shoulder flexion from 0° to maximum elevation (dynamic task). Surface electrodes were placed on the deltoid, pectoralis major, infraspinatus, and teres minor muscles to measure the activities of the shoulder muscles during each task. The muscle activities during the static task were compared using a 2-way analysis of variance with repeated measures of the 2 factors, loading condition and flexion position, and a paired t test was used for comparisons between the 2 conditions during the dynamic task (significance level set at P < .05). RESULTS: For the static task, the Flex-band condition significantly increased the deltoid middle and posterior activities by 2-15 times and the infraspinatus and teres minor activities by 2-3 times compared with the Normal-flex condition at all positions. In contrast, the Flex-band condition significantly decreased (by about half) the activities of the deltoid anterior (at 120° and 150°) and pectoralis major (at all positions) compared with the Normal-flex condition. For the dynamic task, the Flex-band condition significantly increased the deltoid middle, deltoid posterior, infraspinatus, and teres minor activities by 2-7 times and decreased the deltoid anterior activity by approximately two-thirds. CONCLUSIONS: Applying isometric horizontal abduction loading during shoulder forward flexion may be useful in improving the imbalanced muscle activities of the glenohumeral joint, such as excessive activity of the deltoid anterior and pectoralis major and dysfunction of the deltoid middle, deltoid posterior, and shoulder external rotator muscles. Shoulder forward flexion with horizontal abduction loading could be available for exercise in patients who have massive rotator cuff tears or who have undergone rotator cuff repair and shoulder arthroplasty.

Conversion of Upper-Limb Inertial Measurement Unit Data to Joint Angles: A Systematic Review.

Inertial measurement units (IMUs) have become the mainstay in human motion evaluation outside of the laboratory; however, quantification of 3-dimensional upper limb motion using IMUs remains challenging. The objective of this systematic review is twofold. Firstly, to evaluate computational methods used to convert IMU data to joint angles in the upper limb, including for the scapulothoracic, humerothoracic, glenohumeral, and elbow joints; and secondly, to quantify the accuracy of these approaches when compared to optoelectronic motion analysis. Fifty-two studies were included. Maximum joint motion measurement accuracy from IMUs was achieved using Euler angle decomposition and Kalman-based filters. This resulted in differences between IMU and optoelectronic motion analysis of 4° across all degrees of freedom of humerothoracic movement. Higher accuracy has been achieved at the elbow joint with functional joint axis calibration tasks and the use of kinematic constraints on gyroscope data, resulting in RMS errors between IMU and optoelectronic motion for flexion-extension as low as 2°. For the glenohumeral joint, 3D joint motion has been described with RMS errors of 6° and higher. In contrast, scapulothoracic joint motion tracking yielded RMS errors in excess of 10° in the protraction-retraction and anterior-posterior tilt direction. The findings of this study demonstrate high-quality 3D humerothoracic and elbow joint motion measurement capability using IMUs and underscore the challenges of skin motion artifacts in scapulothoracic and glenohumeral joint motion analysis. Future studies ought to implement functional joint axis calibrations, and IMU-based scapula locators to address skin motion artifacts at the scapula, and explore the use of artificial neural networks and data-driven approaches to directly convert IMU data to joint angles.

Anatomical, functional and biomechanical review of the glenoid labrum.

The glenohumeral joint is the most mobile joint in the human skeleton, supported by both active and passive stabilisers. As one of the passive stabilisers, the glenoid labrum has increasingly been recognised to play an important role in stability of the glenohumeral joint, acting to maintain intraarticular pressure, centralise the humeral head and contribute to concavity-compression stability. Several studies have investigated the macro- and micro-anatomical features of the labrum as well as its biomechanical function. However, in order to better understand the role of the labrum and its mechanics, a comprehensive anatomical, functional and biomechanical review of these studies is needed. Therefore, this article reviews the current literature detailing anatomical descriptions of the glenoid labrum, with an emphasis on its function(s) and biomechanics, as well as its interaction with neighbouring structures. The intimate relationship between the labrum and the surrounding structures was found to be important in glenohumeral stability, which owes further investigation into the microanatomy of labrum to better understand this relationship.

Glenohumeral joint dislocation is rare in children with proximal humeral fractures: a descriptive study and literature review.

BACKGROUND: Glenohumeral dislocation combined with fracture of the proximal humerus is extremely rare in children, and this study aims to investigate its incidence in the pediatric population and review the treatment strategy for this condition. METHODS: Between Jan 2014 and Jan 2019, 280 patients with unilateral proximal humeral fractures were retrospectively reviewed. Imaging and follow-up notes were reviewed for patients with a predilection for glenohumeral joint dislocation. Six (2.14%) patients between the ages of 5 and 10 years were confirmed as glenohumeral joint dislocation and included in the study. All these patients underwent closed reduction and external fixation under general anesthesia. RESULTS: Out of 280 patients with proximal humeral fractures, only 6 patients, including 4 males and 2 females, were confirmed as glenohumeral joint dislocation. ROM was normal compared with the contralateral shoulder in every patient at the last follow-up. There was no case of radiological abnormality, including avascular necrosis or devascularization of the humeral head. CONCLUSIONS: Glenohumeral dislocation is a rare entity associated with the proximal humerus fracture in children, with an overall incidence in our case series was 2.14%. Reduction and stabilization of such injury using an external fixator is a suitable choice for pediatric patients that failed closed reduction.