The incidence of primary reverse total shoulder arthroplasty (rTSA) and the prevalence of obesity have increased in the United States. Despite this, the literature assessing the effect of morbid obesity (body mass index≥40 kg/m²) on perioperative surgical outcomes remains inconsistent. A retrospective review of consecutive elective primary rTSA cases from January 2016 through September 2023 at a single tertiary referral center was performed. All cases involved a short-stem humeral component and screw-in glenoid baseplate from the same implant manufacturer. Surgical and patient demographic data were collected. Morbidly obese patients were propensity matched at least 1:1 with non-morbidly obese patients based on age, gender, modified 5-item frailty index score, adjusted Charlson comorbidity index score, and 12-month preoperative emergency department (ED) visit. Regression analysis was utilized to assess the relationship between morbid obesity and operative time, length of stay, intraoperative total blood volume loss, surgical postoperative complications, in-hospital medical complications, disposition, and 90-day ED return and readmission. There were a total of 175 short-stem rTSA cases performed with a median age of 71 years (interquartile range: 66, 76), of which 19 (10.9%) had a body mass index ≥40 kg/m². These 19 patients were propensity score matched to 41 non-morbidly obese patients (9 at 1:3, 4 at 1:2, and 6 at 1:1). There were no significant differences between the groups with regard to intraoperative total blood volume loss, operative time, need for transfusion, hospital length of stay, discharge disposition, prevalence for 90-day return to ED, or unplanned 90-day readmission. Morbid obesity should not be considered an absolute contraindication for elective rTSA, particularly in patients who have undergone appropriate preoperative medical clearance.

Several studies have demonstrated that diapausing insects upregulate glycerol production in response to cold temperatures. However, relatively few studies have investigated whether diapause can independently trigger increased glycerol production. In other words, little research has been dedicated to analyzing whether diapause and glycerol upregulation are linked. If a linkage between these two elements in insects exists, then photoinduced diapausing insects should upregulate glycerol production, even without exposure to cold temperatures. The current study examines whether this linkage exists in the tobacco hornworm pupae (Manduca sexta). Tobacco hornworms will enter a pupal diapause if presented with consistently short photoperiods, most notably 12 hours of daylight followed 12 hours of darkness. Regarding temperature, photoinduction of diapause in the tobacco hornworm is optimal at 26 degrees celsius. Using a spectrophotometric assay, glycerol levels in hemolymph were assessed in non-diapausing pupae shortly after pupation and in diapausing pupae after 16 days of pupation. Interestingly, non-diapausing pupae contained significantly higher glycerol levels in hemolymph compared to diapausing pupae. Furthermore, non-diapausing pupae produced approximately .099 M glycerol and diapausing pupae produced .085 M glycerol. This study provides evidence that glycerol upregulation and diapause are not linked in Manduca sexta, but are rather two separate events with two distinct causes. Nevertheless, the results are valuable since non-diapause specimens produced more glycerol than diapausing specimens, and moderately high concentrations of glycerol were found in both diapausing pupae and non-diapausing pupae.