Dog walking is often suggested as an effective modality for improving physical health in elderly Americans. 1 Nonetheless, injury risks associated with dog walking remain obscure. Considering that older patients are more vulnerable to fractures owing to falls or axial muscle compression forces inherent to walking motions, a risk-benefit analysis with respect to dog walking as an exercise alternative is essential to minimizing injury risk. 2 This study represents a comprehensive, up-todate investigation into fracture risk in older adults who use leashes when walking dogs.

SUMMARY We found that exposure of adult animals to caloriedense foods rapidly abolished expression of mitofusin 2 (Mfn2), a gene promoting mitochondrial fusion and mitochondrion-endoplasmic reticulum interactions, in white and brown fat. Mfn2 mRN was also robustly lower in obese human subjects compared with lean controls. Adipocyte-specific knockdown of Mfn2 in adult mice led to increased food intake, adiposity, and impaired glucose metabolism on standard chow as well as on a diet with high calorie content. The body weight and adiposity of mature adipocyte-specific Mfn2 knockout mice on a standard diet were similar to those of control mice on a high-fat diet. The transcriptional profile of the adipose tissue in adipocyte-specific Mfn2 knockout mice was consistent with adipocyte proliferation, increased lipogenesis at the tissue level, and decreased glucose utilization at the systemic level. These observations suggest a possible crucial role for mitochondrial dynamics in adipocytes in initiating systemic metabolic dysregulation.

Introduction:The prevalence of obesity continues to rise in parallel with demand for total hip arthroplasty (THA). This study aims to report obesity trends in primary THA and its effects on procedure outcomes in the United States, stratifying based on Body Mass Index (BMI). Methods: Primary THA procedures were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database (2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016). Patient demographic (including BMI), primary outcomes (death; serious morbidity), and secondary outcome variables were analyzed. Using BMI comparison groups (Obese: BMI > 30 [O]; Morbidly Obese: BMI > 40 [MO]) for case populations, univariate, propensity score-matched, and multivariate logistic regression analyses were performed. Results: The prevalence of obesity increased among primary THA (2008: 546/1200 [45.5%], 2016: 16,078/ 34,137 [47.1%]) cases. Data on 135,013 primary THA cases were analyzed. Propensity score-matched analyses demonstrated that both serious morbidity

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Introduction: Prosthetic hip dislocation is a common, costly complication of total hip arthroplasty (THA). Despite this, the national burden of prosthetic hip dislocations remains uncharacterised in the United States, especially pertaining to injuries occurring years after the index procedure. This study examines historical and projected national estimates of prosthetic hip dislocations presenting to U.S. emergency departments between 2000 and 2035. Methods: We conducted a cross-sectional, retrospective epidemiological study using narratives in the National Electronic Injury Surveillance System (NEISS) database (2000–2017) to identify an estimated 64,671 prosthetic hip implant dislocations presenting to U.S. emergency departments. Estimates for the prevalence of individuals living with a total hip implant were derived from the literature. Results: The national estimate of prosthetic hip dislocations presenting to U.S. emergency departments rose significantly ( p < 0.001) between 2000 ( n = 2395; 95% CI, 1264–3526) and 2017 ( n = 8094; 95% CI, 4276–11,912). These increases are likely driven by increased numbers of people living with THA overall, since between 2000 and 2017, the average incidence of prosthetic hip dislocation (0.14%; CI 0.08–0.21%) in patients living with hip implants has not changed significantly. Linear regression modeling (R2 = 0.7, p < 0.01) projected an increasing number of dislocations through 2035, predicting 10,446 national cases per year by this date. Conclusions: Driven by increases in THA, the annual volume of prosthetic hip dislocations presenting to U.S. emergency departments has increased significantly since 2000 and is projected to continue to rise sharply. Future advances in surgical technique, prosthesis design, and injury prevention policies aimed at decreasing the rate of THA dislocation would help alleviate this mounting national health burden.

Introduction: Orthopaedic surgeons often cite concern for a learning curve as a barrier to adopting the direct anterior approach (DAA) for total hip arthroplasty (THA) while transitioning from other approaches. Studies both assessing and describing a practical approach and strategy to safely accomplish this transition, as well as the effect on clinical outcomes, are not well described. Methods: This prospective study compares a single surgeon's operative results and complications for the first consecutive 100 direct anterior THA to the last 100 consecutive posterior THA after 7 years in practice. The regimented and disciplined learning strategy used to implement the DAA is detailed in this study. The data were analyzed using univariate and multivariate regression models. Results: Univariate analyses identified significant differences in sex, age, Asian race, and diagnostic cause for THA between the two cohorts. Multivariate analyses controlled for these differences and showed that relative to posterior THA, direct anterior THA cases were associated with 7-minute longer procedures (P = 0.002) and lengths of stay that were 0.7 days fewer (P = 0.013). No significant differences were present in the estimated blood loss, and importantly, no significant differences in death or surgical complication rates between cohorts. Discussion: This study suggests that the DAA for THA can be safely implemented without the increased and adverse risk to the patient when a structured learning process is maintained and meticulously performed.