Feedback cues improve the alignment and technique of children performing ACL injury prevention exercises.

OBJECTIVES: The appropriateness of neuromuscular training exercises across different age groups has not yet been investigated, particularly in younger children. The purpose of this study was to determine which neuromuscular training exercises can be performed with proper neutral alignment in various age groups. METHODS: Seven exercises were selected for evaluation in children ranging from 8 to 17 years of age who were recruited from schools and youth sports organisations. Participants completed two trials of each exercise and were judged on maintaining neutral body alignment after receiving visual/verbal instruction on the first trial and feedback cues on the second trial. Three evaluators judged each exercise, which was deemed as correct when at least two evaluators agreed that neutral alignment was maintained. Comparisons were made across ages and between sex using the χ² test or Fisher's exact test. The proportions of participants who performed the exercise correctly were also compared before and after feedback cues were provided. RESULTS: A total of 360 participants were evaluated (8-11 years: 165, 54% female; 12-15 years: 136, 40% female, 16-17 years: 59, 53% female). There were no significant differences in performance across ages and sex for nearly all exercises. The majority of children were not able to complete the exercises with proper alignment. The use of feedback cues significantly increased the proportion of participants who correctly completed the exercise (p<0.001). CONCLUSIONS: These results demonstrate the importance of training coaches and physical education teachers to provide cues that reinforce proper technique during anterior cruciate ligament injury prevention exercises. Children should perform common neuromuscular training exercises with feedback on proper technique. LEVEL OF EVIDENCE: IV (case series).

Knee MLI Injuries: Common Problems and Solutions.

The multiple ligament injured knee presents a challenge with regard to management and treatment. Immediate management of the acute injury requires special attention and thorough examination because knee dislocations have been associated with significant complications. Treatment options range from closed reduction and immobilization to surgical repair and/or reconstruction of the injured ligaments. This article focuses on complications that may result from surgical treatments of the multiple ligament injured knee and ways of prevention. These complications include vascular and neurologic complications, venous thromboembolic events, arthrofibrosis, compartment syndrome, wound problems, heterotopic ossification, fractures and avascular necrosis, tunnels positioning complications, and malalignment.

Fusion of Regionally Specified hPSC-Derived Organoids Models Human Brain Development and Interneuron Migration.

Organoid techniques provide unique platforms to model brain development and neurological disorders. Whereas several methods for recapitulating corticogenesis have been described, a system modeling human medial ganglionic eminence (MGE) development, a critical ventral brain domain producing cortical interneurons and related lineages, has been lacking until recently. Here, we describe the generation of MGE and cortex-specific organoids from human pluripotent stem cells that recapitulate the development of MGE and cortex domains, respectively. Population and single-cell RNA sequencing (RNA-seq) profiling combined with bulk assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) analyses revealed transcriptional and chromatin accessibility dynamics and lineage relationships during MGE and cortical organoid development. Furthermore, MGE and cortical organoids generated physiologically functional neurons and neuronal networks. Finally, fusing region-specific organoids followed by live imaging enabled analysis of human interneuron migration and integration. Together, our study provides a platform for generating domain-specific brain organoids and modeling human interneuron migration and offers deeper insight into molecular dynamics during human brain development.