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Myotonic Dystrophy type 1 (DM1), a highly prevalent form of muscular dystrophy, is caused by (CTG)n repeat expansion in the DMPK gene. Much of DM1 research has focused on the effects within the muscle and neurological tissues; however, DM1 patients also suffer from various metabolic and liver dysfunctions such as increased susceptibility to metabolic dysfunction-associated fatty liver disease (MAFLD) and heightened sensitivity to certain drugs. Here, we generated a liver-specific DM1 mouse model that reproduces molecular and pathological features of the disease, including susceptibility to MAFLD and reduced capacity to metabolize specific analgesics and muscle relaxants. Expression of CUG-expanded (CUG)exp repeat RNA within hepatocytes sequestered muscleblind-like proteins and triggered widespread gene expression and RNA processing defects. Mechanistically, we demonstrate that increased expression and alternative splicing of acetyl-CoA carboxylase 1 drives excessive lipid accumulation in DM1 livers, which is exacerbated by high-fat, high-sugar diets. Together, these findings reveal that (CUG)exp RNA toxicity disrupts normal hepatic functions, predisposing DM1 livers to injury, MAFLD, and drug clearance pathologies that may jeopardize the health of affected individuals and complicate their treatment. Liver dysfunctions are understudied in myotonic dystrophy (DM1) but impact metabolic health, drug sensitivity and treatment paradigms for the affected population. Here, Dewald et al. generated liver-specific DM1 mice to demonstrate that CUG-repeat RNA toxicity predisposes the liver to MAFLD and drug metabolism defects. [ABSTRACT FROM AUTHOR]

Background: Surgical treatment options of discoid lateral meniscus in pediatric patients consist of saucerization with or without meniscal repair, meniscocapular stabilization, and, less often, subtotal meniscectomy. Purpose: To describe a large, prospectively collected multicenter cohort of discoid menisci undergoing surgical intervention, and further investigate corresponding treatment of discoid menisci. Study Design: Cohort study; Level of evidence, 3. Methods: A multicenter quality improvement registry (16 institutions, 26 surgeons), Sports Cohort Outcomes Registry, was queried. Patient characteristics, discoid type, presence and type of intrasubstance meniscal tear, peripheral rim instability, repair technique, and partial meniscectomy/debridement beyond saucerization were reviewed. Discoid meniscus characteristics were compared between age groups (<14 and >14 years old), based on receiver operating characteristic curve, and discoid morphology (complete and incomplete). Results: In total, 274 patients were identified (mean age, 12.4 years; range, 3-18 years), of whom 55.6% had complete discoid. Meniscal repairs were performed in 55.1% of patients. Overall, 48.5% of patients had rim instability and 36.8% had >1 location of peripheral rim instability. Of the patients, 21.5% underwent meniscal debridement beyond saucerization, with 8.4% undergoing a subtotal meniscectomy. Patients <14 years of age were more likely to have a complete discoid meniscus (P <.001), peripheral rim instability (P =.005), and longitudinal tears (P =.015) and require a meniscal repair (P <.001). Patients ≥14 years of age were more likely to have a radial/oblique tear (P =.015) and require additional debridement beyond the physiologic rim (P =.003). Overall, 70% of patients <14 years of age were found to have a complete discoid meniscus necessitating saucerization, and >50% in this young age group required peripheral stabilization/repair. Conclusion: To preserve physiological "normal" meniscus, a repair may be indicated in >50% of patients <14 years of age but occurred in <50% of those >14 years. Additional resection beyond the physiological rim may be needed in 15% of younger patients and 30% of those aged >14 years. [ABSTRACT FROM AUTHOR]

Background: Surgical treatment options of discoid lateral meniscus in pediatric patients consist of saucerization with or without meniscal repair, meniscocapular stabilization, and, less often, subtotal meniscectomy., Purpose: To describe a large, prospectively collected multicenter cohort of discoid menisci undergoing surgical intervention, and further investigate corresponding treatment of discoid menisci., Study Design: Cohort study; Level of evidence, 3., Methods: A multicenter quality improvement registry (16 institutions, 26 surgeons), Sports Cohort Outcomes Registry, was queried. Patient characteristics, discoid type, presence and type of intrasubstance meniscal tear, peripheral rim instability, repair technique, and partial meniscectomy/debridement beyond saucerization were reviewed. Discoid meniscus characteristics were compared between age groups (<14 and >14 years old), based on receiver operating characteristic curve, and discoid morphology (complete and incomplete)., Results: In total, 274 patients were identified (mean age, 12.4 years; range, 3-18 years), of whom 55.6% had complete discoid. Meniscal repairs were performed in 55.1% of patients. Overall, 48.5% of patients had rim instability and 36.8% had >1 location of peripheral rim instability. Of the patients, 21.5% underwent meniscal debridement beyond saucerization, with 8.4% undergoing a subtotal meniscectomy. Patients <14 years of age were more likely to have a complete discoid meniscus ( P < .001), peripheral rim instability ( P = .005), and longitudinal tears ( P = .015) and require a meniscal repair ( P < .001). Patients ≥14 years of age were more likely to have a radial/oblique tear ( P = .015) and require additional debridement beyond the physiologic rim ( P = .003). Overall, 70% of patients <14 years of age were found to have a complete discoid meniscus necessitating saucerization, and >50% in this young age group required peripheral stabilization/repair., Conclusion: To preserve physiological "normal" meniscus, a repair may be indicated in >50% of patients <14 years of age but occurred in <50% of those >14 years. Additional resection beyond the physiological rim may be needed in 15% of younger patients and 30% of those aged >14 years., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: See the Appendix (available in the online version of this article). AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Background: The incidence of meniscus tears and ACL tears in pediatric patients continues to rise, bringing to question the risk factors associated with these injuries. As meniscus tears are commonly repaired in pediatric populations, the epidemiology of repairable meniscus tears is an important for consideration for surgeons evaluating treatment options., Purpose: To describe meniscal tear patterns in pediatric and adolescent patients who underwent meniscal repair across multiple institutions and surgeons, as well as to evaluate the relationship between age, sex, and body mass index (BMI) and their effect on the prevalence, type, and displacement of repaired pediatric meniscal tears., Study Design: Case series; Level of evidence, 4., Methods: Data within a prospective multicenter cohort registry for quality improvement, Sport Cohort Outcome Registry (SCORE), were reviewed to describe repaired meniscal tear patterns. All consecutive arthroscopic meniscal repairs from participating surgeons in patients aged <19 years were analyzed. Tear pattern, location, and displacement were evaluated by patient age, sex, and BMI. A subanalysis was also performed to investigate whether meniscal tear patterns differed between those occurring in isolation or those occurring with a concomitant anterior cruciate ligament (ACL) injury. Analysis of variance was used to generate a multivariate analysis of specified variables. Sex, age, and BMI results were compared across the cohort., Results: There were 1185 total meniscal repairs evaluated in as many patients, which included 656 (55.4%) male and 529 (44.6%) female patients. Patients underwent surgery at a mean age of 15.3 years (range, 5-19 years), with a mean BMI of 24.9 (range, 12.3-46.42). Of the 1185 patients, 816 (68.9%) had ACL + meniscal repair and 369 (31.1%) had isolated meniscal repair. The male patients underwent more lateral tear repairs than the female patients (54.3% to 40.9%; P < .001) and had a lower incidence of medial tear repair (32.1% vs 41.4%; P < .001). Patients with repaired lateral tears had a mean age of 15.0 years, compared with a mean age of 15.4 years for patients with repaired medial or bilateral tears ( P = .001). Higher BMI was associated with "complex" and "radial" tear repairs of the lateral meniscus ( P < .001) but was variable with regard to medial tear repairs., Conclusion: In pediatric and adolescent populations, the data suggest that the surgical team treating knees with potential meniscal injury should be prepared to encounter more complex meniscal tears, commonly indicated in those with higher BMI, while higher rates of lateral meniscal tears were seen in male and younger patients. Future studies should analyze correlates for meniscal repair survival and outcomes in this pediatric cohort undergoing knee surgery.

Introduction: The American Academy of Orthopaedic Surgeons (AAOS) created an evidence-based clinical practice guideline for the care of pediatric diaphyseal femur fractures in 2010. Our institution implemented checklists based off these guidelines embedded in a standardized EMR order. The purpose of this study was to describe compliance with checklist completion and to assess safety improvement in a large urban pediatric hospital., Methods: Retrospective and prospective data were collected from 2 years before and 5 years after checklist implementation. This included the patient safety checklists from August 2011 through August 2016. Patients aged 0 to 18 years with a diaphyseal femur fracture were queried from the EMR and included in this study. Patient charts were reviewed for complications, including nerve injury, pressure sore, leg length discrepancy, loss of reduction, failure of fixation, nonunion, delayed union, and infection. Compliance rates were reported based on the AAOS clinical practice guidelines., Results: A total of 313 patients for the postchecklist period were reviewed in this study. Of 219 patients eligible for inclusion, 198 had checklists completed (group B). This group was compared with 100 patients with diaphyseal femur fractures from the period before implementation of the checklist (group A). We found no statistical difference in the number of patients with complications between groups (12% in both groups, P = 0.988). Postoperative checklists demonstrated that 89.9% of patients (178/198) received age-appropriate treatment consistent with the AAOS guideline recommendations after implementation of the checklist. Before the checklist implementation (group A), 94% (94/100) adhered to the guidelines., Conclusion: This study reveals high compliance rates with the AAOS evidence-based clinical practice guideline for the management of pediatric femur fractures. Implementing standardized checklists is possible by embedding them into the EMR. Implementation of checklists did not improve compliance or patient outcomes., (Copyright © 2021 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)