Cross-sectional areas of rotator cuff muscles in males without tears on shoulder MRI.

OBJECTIVE: To establish reference values of rotator cuff (RC) cross sectional area (CSA) in males. MATERIALS AND METHODS: We retrospectively analyzed shoulder MRIs from 500 patients aged 13-78 years, grouped as follows (N=100 in each): <20, 20-30, 30-40, 40-50, >50 years. All examinations were reviewed to exclude prior surgery, tears, or significant RC pathology. We segmented a standardized T1 sagittal MR image in each case to obtain CSA of supraspinatus (SUP), infraspinatus/teres minor (INF), and subscapularis (SUB) muscles. Across age groups, we recorded individual and total muscle CSA. We also performed ratios between individual muscle CSA and total CSA to examine total muscle mass contribution over age groups. We tested for differences between age groups controlled for BMI. RESULTS: CSAs for SUP, INF, SUB, and total RC CSA were lower in subjects >50 years compared to all other groups (P<0.003 for all comparisons), persisting after controlling for BMI (P<0.03). Relative contribution of SUP CSA to total RC CSA was stable across age groups (P>0.32). INF CSA relative to total RC CSA increased with age, whereas SUB decreased (P<0.005). Subjects >50 years showed lower SUP (-15%), INF (-6%), and SUB (-21%) CSA, when compared to mean CSAs of all subjects <50 years. Total RC CSA significantly correlated with age (r=-0.34, P<0.001), persisting after controlling for BMI (r=-0.42, P<0.001). CONCLUSION: RC muscles in male subjects with no tears on MRI show decreasing CSA with age, independent of BMI.

Systematic review of prevalence, risk factors, and management of instability following reverse shoulder arthroplasty.

Background: Since its approval for use, reverse shoulder arthroplasty (RSA) has become the primary treatment for cuff tear arthropathy, with indications expanding more recently to include revision fracture, osteoarthritis with significant glenoid bone loss, tumor, and chronic instability. Instability is a well-described postoperative complication, occurring in 1to 31% of relatively small cohorts and case series. Given the relative infrequency of instability, there remains a need for a comprehensive review of instability with a focus on risk factors and management. Our goal of this systematic review is to describe the prevalence, risk factors, and management strategies for instability following RSA. Methods: A systematic review of the PubMed, EMBASE, MEDLINE, Scopus, and Cochrane Library databases was performed according to PRISMA guidelines. Inclusion criteria included primary RSA cohorts ≥ 100 patients, revision RSA cohorts of any size, and minimum 1-year follow-up. The primary outcome of interest was postoperative instability. MINORS criteria were used to assess study bias. Descriptive statistical analysis was performed with data reported as ranges. Results: Seventeen studies that included 7885 cases of RSA were reviewed. The mean follow-up ranged from 12 to 84 months. Mean age ranged from 64 to 77 years old, and males represented 19 to 39% of cohorts. There were 204 (2.5%) dislocations in 7885 cases, accounting for a rate of instability from 0.4 to 49% across all studies. By intervention, instability rates ranged from 1 to 5% (primary RSA cases), 1 to 49% (revision RSA cases only), and 0.4 to 10% (mixed cohorts). Subscapularis insufficiency and proximal humerus fractures, and fracture sequelae (malunion and nonunion) were identified as risk factors for instability. Closed reduction and casting and revision RSA were reported as successful treatment strategies with acceptable rates of stable prostheses (28-100% and 55-100%, respectively, across studies). Hemiarthroplasty or resection arthroplasty due to recurrent instability was not uncommon after 2 or more episodes of instability. Conclusion: Instability following RSA occurs infrequently (1-5%) following primary RSA and more commonly following revision RSA (1-49%). RSA for acute proximal humerus fracture and fracture sequelae carries a higher risk of instability. Subscapularis repair appears to be a protective factor. While instability may be successfully treated with closed management or revision RSA, recurrent instability may ultimately require hemiarthroplasty or resection arthroplasty.

Rehabilitation variability after rotator cuff repair.

BACKGROUND: There has been increasing recognition of the importance for standardized postoperative rehabilitation protocols. Despite published guidelines in 2016 by the American Society of Shoulder and Elbow Therapists (ASSET), optimal postoperative rehabilitation after rotator cuff repair (RCR) remains an area of active academic debate. The goals of this study were (1) to assess the variability of RCR rehabilitation protocols published online, (2) to study the congruence between online RCR rehabilitation protocols and the ASSET consensus statement, and (3) to identify differences in online RCR rehabilitation protocols from before and after 2016. METHODS: A web-based search was conducted for publicly available RCR rehabilitation protocols from websites of all Accreditation Council for Graduate Medical Education (ACGME) academic orthopedic institutions. A supplemental 10-page Google search was also performed with the search terms "rotator cuff repair rehabilitation protocol." Collected protocols were grouped by tear size (small/medium or large/massive) and examined for information relating to the following categories: protocol demographics, adjunctive therapy use, immobilization/range of motion, and strengthening. Findings were compared to the ASSET statement's recommendations. Protocols published before and after ASSET's 2016 publication were compared for differences. RESULTS: A total of 66 online RCR rehabilitation protocols were collected. Only 16 of 187 (8.5%) ACGME institutions provided online RCR rehabilitation protocols. The collected protocols recommend more aggressive rehabilitation in comparison to ASSET, specifically regarding immobilization time, passive range of motion initiation, active assisted range of motion initiation, and strengthening initiation (P < .001). Protocols published after 2016 trended toward more conservative recommendations in comparison to protocols published before 2016. Regardless of this trend, the majority of these recommendations were still largely more aggressive than ASSET's recommendations. CONCLUSION: Despite an attempt by ASSET to provide standardization, this study highlights the marked variations that still exist regarding RCR rehabilitation. Additionally, online RCR rehabilitation protocols tend to make more aggressive recommendations than the ASSET consensus statement. Further research is needed to address these variations and to either validate, alter, or reject the ASSET recommendations.