Background: Reverse shoulder arthroplasty (RSA) is an alternative to anatomic total shoulder arthroplasty (TSA) for treating glenohumeral osteoarthritis (OA), particularly in elderly patients. This study evaluates 90-day postoperative complication rates and identifies risk factors for adverse outcomes in RSA and TSA patients. Methods: A retrospective cohort study was conducted using the TriNetX Research NLP Network to identify patients aged 65–90 years who underwent RSA or TSA for OA from 2006 to 2024. 1:1 propensity score matching controlled for demographics and comorbidities. Orthopedic and infectious complications were compared using multivariate logistic regression. Results: The final matched cohort included 4,117 RSA and TSA patients. RSA was associated with significantly higher odds of orthopedic complications compared to TSA. Significant risk factors for orthopedic complications in RSA included nicotine dependence (OR, 1.592; P=0.001) and hypertension (OR, 1.545; P=0.001). In TSA, risk factors included male sex (OR, 0.702; P=0.005), chronic obstructive pulmonary disease (OR, 1.650; P=0.016), and obesity (OR, 1.776; P<0.001). For infections, RSA risk factors were male sex (odds ratio [OR], 1.698; P=0.005), heart failure (OR, 2.396; P<0.001), and diabetes (OR, 1.525; P=0.039). Diabetes was the only significant risk factor in TSA (OR, 2.453; P=0.003). Conclusions: RSA carries a higher risk of orthopedic complications and infection than TSA within 90 days. Distinct risk factors for each procedure highlight the need for patient-specific risk stratification to optimize preoperative assessment and surgical decision-making. Level of evidence: III.

Microgravity in spaceflight produces headward fluid shifts which probably contribute to Spaceflight-Associated Neuro-Ocular Syndrome (SANS). Developing new methods to mitigate these shifts is crucial for preventing SANS. One possible strategy is the use of self-generated lower body negative pressure (LBNP). This study evaluates biological or physiological effects induced by bed rest to simulate adaptations to microgravity. Participants were tested during powered LBNP and dynamic self-generated (SELF) LBNP at 25 mmHg for 15 min. The results were compared to the physiologic responses observed in seated upright and supine positions without LBNP, which served as controls for normal gravitational effects on fluid dynamics. Eleven participants’ (five male, six female) heart rates, blood pressures, and cross-sectional areas (CSA) of left and right internal jugular veins (IJV) were monitored. Self-generated LBNP, which requires mild to moderate physical activity, significantly elevated heart rate and blood pressure (p < 0.01). Self-generated LBNP also significantly reduced right IJV CSA compared to supine position (p = 0.005), though changes on the left side were not significant (p = 0.365). While the effects of SELF and traditional LBNP on IJV CSA were largely similar, traditional LBNP significantly reduced IJV CSA on both sides. Given its low mass, volume, and power requirements, SELF LBNP is a promising countermeasure against SANS. Results from this study warrant longer-term studies of SELF LBNP under simulated spaceflight conditions.

Background: Massive irreparable rotator cuff tears are a significant challenge for shoulder function, with tendon transfers emerging as potential solutions. Objective: This systematic review aims to comprehensively evaluate the current evidence on the outcomes of lower trapezius transfer for the treatment of massive rotator cuff tears Methods: This systematic review examines the use of trapezius transfer in managing these tears. Following PRISMA guidelines, a search of Medline, Embase, and Cochrane was conducted through March 2024 for studies on trapezius tendon transfer. Results: The review analyzed data from 214 patients (161 males, 53 females) with an average age of 58 years (range: 31-73 years), focusing on surgical technique, complications, follow-up duration, and outcomes. Most procedures utilized an Achilles allograft, with reported complications including retear rates of 7.5% and surgical infections in 2.3% of cases. The average follow-up was 38.4 months, with 80% to 100% of patients returning to previous activity levels. Conclusion: This review highlights the effectiveness of lower trapezius tendon transfer, particularly using an Achilles allograft, in enhancing pain relief, shoulder mobility, and overall function. Despite some complications, the high return-to-activity rate underscores the procedure’s utility in restoring normalcy and productivity for patients with massive rotator cuff tears. Future research should aim to standardize operative and postoperative protocols to optimize outcomes and reduce complications.