Reverse Shoulder Arthroplasty with Bony and Metallic versus Standard Bony Reconstruction for Severe Glenoid Bone Loss. A Retrospective Comparative Cohort Study

There are different techniques to address severe glenoid erosion during reverse shoulder arthroplasty (RSA). This study assessed the clinical and radiological outcomes of RSA with combined bony and metallic augment (BMA) glenoid reconstruction compared to bony augmentation (BA) alone. A review of patients who underwent RSA with severe glenoid bone loss requiring reconstruction from January 2017 to January 2019 was performed. Patients were divided into two groups: BMA versus BA alone. Clinical outcome measurements included two years postoperative ROM, Constant score, subjective shoulder value (SSV), and the American Shoulder and Elbow Surgeons Shoulder (ASES) score. Radiological outcomes included radiographic evidence of scapular complications and graft incorporation. The BMA group had significantly different glenoid morphology (p < 0.001) and greater bone loss thickness than the BA group (16.3 ± 3.8 mm vs. 12.0 ± 0.0 mm, p = 0.020). Both groups had significantly improved ROM (anterior forward flexion and external rotation) and clinical scores (Constant, SSV and ASES scores) at 2 years. Greater improvement was observed in the BMA group in terms of anterior forward flexion (86.3° ± 27.9° vs. 43.8° ± 25.6°, p = 0.013) and Constant score (56.6 ± 10.1 vs. 38.3 ± 16.7, p = 0.021). The BA group demonstrated greater functional and clinical improvements with higher postoperative active external rotation and ASES results (active external rotation, 49.4° ± 17.0° vs. 29.4° ± 14.7°, p = 0.017; ASES, 89.1 ± 11.3 vs. 76.8 ± 11.0, p = 0.045). The combination use of bone graft and metallic augments in severe glenoid bone loss during RSA is safe and effective and can be considered in cases of severe glenoid bone loss where bone graft alone may be insufficient.

Supraspinatus-to-Glenoid Contact Occurs During Standardized Overhead Reaching Motion

Background: Rotator cuff tears may result from repeated mechanical deformation of the cuff tendons, and internal impingement of the supraspinatus tendon against the glenoid is one such proposed mechanism of deformation. Purpose: To (1) describe the changing proximity of the supraspinatus tendon to the glenoid during a simulated overhead reaching task and (2) determine the relationship between scapular morphology and this proximity. Additionally, the patterns of supraspinatus-to-glenoid proximity were compared with previously described patterns of supraspinatus-to-coracoacromial arch proximity. Study Design: Descriptive laboratory study. Methods: Shoulder models were created from magnetic resonance images of 20 participants. Standardized kinematics were imposed on the models to simulate functional reaching, and the minimum distances between the supraspinatus tendon and the glenoid and the supraspinatus footprint and the glenoid were calculated every 5° between 0° and 150° of humerothoracic elevation. The angle at which contact between the supraspinatus and the glenoid occurred was documented. Additionally, the relationship between glenoid morphology (version and inclination) and the contact angle was evaluated. Descriptive statistics were calculated for the minimum distances, and glenoid morphology was assessed using Pearson correlation coefficients and simple linear regressions. Results: The minimum distances between the tendon and the glenoid and between the footprint and the glenoid decreased as elevation increased. Contact between the tendon and the glenoid occurred in all participant models at a mean elevation of 123° ± 10°. Contact between the footprint and the glenoid occurred in 13 of 20 models at a mean of 139° ± 10°. Less glenoid retroversion was associated with lower tendon-to-glenoid contact angles ( r = –0.76; R 2 = 0.58; P < .01). Conclusion: This study found that the supraspinatus tendon progressively approximated the glenoid during simulated overhead reaching. Additionally, all participant models eventually made contact with the glenoid by 150° of humerothoracic elevation, although anatomic factors influenced the precise angle at which contact occurred. Clinical Relevance: Contact between the supraspinatus and the glenoid may occur frequently within the range of elevation required for overhead activities. Therefore, internal impingement may be a prevalent mechanism for rotator cuff deformation that could contribute to cuff pathology.

Increased Glenoid Index as a Risk Factor for Pediatric and Adolescent Anterior Glenohumeral Dislocation: An MRI-Based, Case-Control Study

Background: In adults, anterior glenohumeral instability has been associated with a tall and narrow glenoid morphology, assessed using the glenoid index (GI; glenoid height-to-width ratio) on magnetic resonance imaging (MRI). This morphological association has not been assessed in children and adolescents. Purpose/Hypothesis: To examine the association of GI and other MRI measurements of interest supported in studies on adults with anterior glenohumeral dislocation in patients aged ≤19 years. We hypothesized that these patients would have a significantly greater GI (relatively taller and narrower glenoid morphology) compared with healthy controls. Study Design: Case-control study; Level of evidence, 3. Methods: An institutional radiology database was queried over a 10-year period to identify patients aged ≤19 years who had been diagnosed with radiographically confirmed anterior shoulder dislocation and who underwent glenohumeral magnetic resonance arthrography as well as those without dislocation with normal shoulder arthrogram studies (controls). Patients with bony Bankart lesions were excluded. The following glenohumeral dimensions were measured on shoulder arthrogram: GI, glenoid version, coracohumeral interval, and rotator interval width/depth. Comparative analysis between the 2 groups was performed using the Student t test for each variable, followed by receiver operating characteristic (ROC) analysis to determine discriminative ability when statistically significant. Results: Overall, 55 participants (33 male and 22 female patients; mean age, 15.4 ± 2.1 years) were enrolled; 22 patients were in included in the dislocator group and 33 patients comprised the control group. The mean GI in the dislocator group was significantly greater than the control group (1.55 ± 0.14 vs. 1.38 ± 0.08; P < .001). ROC analysis revealed adequate discrimination of GI in predicting glenohumeral dislocation (area under the curve = 0.88). A GI ≥1.45 was 83% sensitive and 79% specific for predicting dislocation in the study cohort. Conclusion: Patients with anterior glenohumeral dislocation had increased GI (taller and narrower glenoid morphology) than controls. This useful MRI measurement may help identify patients at risk for primary or recurrent anterior glenohumeral instability events and may therefore help with guiding treatment and prevention.