Aims Reverse shoulder arthroplasty (RSA) reliably improves shoulder pain and function for a variety of indications. However, the safety and efficacy of RSA in elderly patients is largely unknown. The purpose of this study was to report the mortality, morbidity, complications, reoperations, and outcomes of primary RSA in patients aged > 80 years. Patients and Methods Between 2004 and 2013, 242 consecutive primary RSAs were performed in patients aged > 80 years (mean 83.3 years (sd 3.1)). Of these, 53 were lost to follow-up before two years and ten had died within two years of surgery, leaving 179 for analysis of survivorship, pain, motion, and strength at a minimum of two years or until revision surgery. All 242 patients were considered for the analysis of 90-day, one-year, and overall mortality, medical complications (90-day and overall), surgical complications, and reoperations. The indications for surgery included rotator cuff arthropathy, osteoarthritis, fracture, the sequela of trauma, avascular necrosis, and rheumatoid arthritis. A retrospective review of the medical records was performed to collect all variables. Survivorship free of revision surgery was calculated at two and five years. Results One patient (0.4%) died within the first 90 days. A total of 45 patients (19%) were known to have died at the time of the final follow-up, with a median time to death of 67.7 months (interquartile range 40.4 to 94.7) postoperatively. Medical complications occurred in six patients (3%) and surgical complications occurred in 21/179 patients (12%). Survivorship free from revision was 98.9% at two years and 98.3% at five years; survivorship free from loosening was 99.5% at final follow-up. The presence of peripheral vascular disease correlated with a higher complication rate. Conclusion Primary RSA was safe and effective in patients aged > 80 years, with a relatively low rate of medical and surgical complications. Thus, age alone should not be a contraindication to primary RSA in patients aged > 80 years. However, a careful evaluation of comorbidities is required in this age group when considering primary RSA. Cite this article: Bone Joint J 2019;101-B:1520–1525

Word Count: 959What is known about this topic? There are numerous mathematical models predicting COVID-19 cases and mortality. The existing models are deterministic or statistical. The models generate estimates of , the reproductive rate of the disease. 0 What are the new findings in your manuscript?  We developed an example COVID-19 model and simulated it under different assumptions.  We generated a statistical model forecasting for New York. 0 How might your results change the direction of research or the focus of clinical practice?Obesity investigators can use mathematical model projections to test prevention and reduction of COVID-19 cases affected by obesity.

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While the latissimus dorsi tendon transfer has historically been performed for posterosuperior RCTs, the lower trapezius transfer is a more anatomic option and has demonstrated promising results in recent studies. Similarly, the pectoralis major transfer has historically been the tendon transfer of choice for anterosuperior RCTs. However, the latissimus dorsi tendon transfer has recently been shown to be a safe and anatomic tendon transfer for subscapularis insufficiency. The treatment of irreparable RCTs involves complex decision making. Tendon transfer procedures can restore the glenohumeral joint force couples, allowing restoration of near-normal shoulder kinematics. Benefits include reliable pain relief, increased function, and increased strength. Proper selection of donor tendon is crucial, and the principles of tendon transfer procedures must be adhered to for maximal benefit.