Orthopaedic Specialty Institute

BackgroundWomen’s Artistic Gymnastics (WAG) is a high-risk sport for concussion, and improved understanding of head kinematics in gymnastics can help inform targeted injury prevention strategies.ObjectiveCharacterize head acceleration exposure in WAG. DesignGymnasts were monitored with mouthpiece sensors and time-synchronized video at all practices over an 11-week period. SettingTwo local USA Gymnastics club gyms. Participants18 competitive women’s artistic gymnasts ages 11–15 (n=8 beginner-level, n=10 advanced-level) Independent variablesFrequency and head kinematics of skills were compared across activity types (i.e., floor, uneven-bars, beam, vault, dance, conditioning, warm-up, basics). Kinematic metrics were compared across the following skill categories: bar-releases, bar-elements, jumps, handsprings, somersaults, somersaults-with-twists, rolls, and inversions.Main Outcome MeasurementsPeak resultant linear (PLA) and rotational acceleration (PRA), and change in rotational velocity associated with PRA (ΔRV) of skills, and rate of skills per gymnastics activity.ResultsMedian (95th%ile) PLA, PRA, and ΔRV of skills were 5.9 (10.0) g, 147 (427) rad/s2, 5.4 (13.3) rad/s, respectively. On average, gymnasts experienced 2.6 skills per practice with PLA greater than 10 g. Activity type and skill category were significantly associated with PLA, PRA, and ΔRV (all p<0.001). Activity type was associated with skill rate. Floor training had the greatest skill rate (27.8 per 30 min), PLA (7.7 g), and ΔRV (8.7 rad/s). Rolls, commonly performed during floor training, had the greatest PRA (372 rad/s2) and ΔRV (9.8 rad/s). ConclusionsGymnasts frequently perform skills that expose them to head acceleration events at magnitudes and rates similar to other contact sports. Gymnasts perform a high-rate of skills on floor exercise which expose them to relatively high magnitude head acceleration events. Injury prevention strategies in gymnastics should target the reduction of head accelerations during floor training, through safety modifications.

Distal radius fractures are a common location of physeal injuries in skeletally immature adolescents. However, reports of athletics-related acute bilateral distal radius physeal injuries are rare. Therefore, there is a need for further literature to demonstrate both the early recognition and prevention of these injuries to ensure young athletes are able to safely train and compete. We present the case of acute bilateral Salter-Harris II distal radii fractures in a 14-year-old athlete during participation in a high-energy impact sport.

Abstract Androgen receptor (AR) and Wnt signaling both play a critical role during prostate cancer progression to castration-resistance prostate cancer (CRPC). Over expression of AR can activate transcriptional activities of Wnt signaling pathway and promote CRPC. Recent data in our laboratory showed a potential co-regulation of srGAP1 (Slit-Robo-GTPase activating protein1) and active Wnt and AR signaling in CRPC. srGAP1 is a downstream component of Slit-Robo signaling. Our data showed that srGAP1 is overexpressed in CRPC cell lines (androgen-insensitive prostate cancer) while absent in both androgen-sensitive cells and in normal prostate epithelial cells. We also detected increased srGAP1 expression in human CRPC tissues compared with normal epithelial prostate and androgen sensitive prostate cancer tissues by immunohistochemistry analysis. When androgen-sensitive LNCaP cells were grown under androgen deprived condition, we observed induced expression of srGAP1. Interestingly, srGAP1 expression was also increased when LNCaP cells were grown under Wnt stimulated conditions. And, srGAP1 expression was decreased when Wnt signaling was inhibited by a Wnt antagonist Wnt-inhibitory factor-1 (WIF-1) in CRPC cell lines. Functional studies using chromatin immmunoprecipitation and luciferase assays were performed to examine whether Wnt transcription factor LEF-1 or TCF-4 binds and activates the srGAP1 promoter. Overexpression of WIF-1 inhibited the promoter activity of srGAP1. Taken together, our results indicated that srGAP1 is co-regulated by both Wnt and AR signaling and srGAP1 may be a new potential Wnt target gene in castration-resistance prostate cancer. Citation Format: Noriko N. Yokoyama, Toshinori Sakai, Zheng Sun, Shujuan Shao, Jiaoti Huang, Bang H. Hoang, Xiaolin Zi. Co-regulation of srGAP1 by Wnt and androgen receptor signaling in castration resistant prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3314. doi:10.1158/1538-7445.AM2014-3314

Musculoskeletal (MSK) conditions account for nearly 15–30 % of encounters in a primary care practice. Yet, studies demonstrate that medical students and residents lack the knowledge and confidence to care for many MSK conditions. This study addresses the design of focused MSK educational practices towards improving students’ knowledge, interest, and confidence for conducting MSK examinations. Students attending a voluntary educational symposium on sports medicine were recruited to participate. The symposium was directed toward teaching elements of the MSK exam. Participants completed validated pre- and post-workshop surveys that assessed confidence in performing MSK examinations as well as satisfaction and perceived importance of MSK education. Additionally, mean survey responses from a convenience group of students who did not participate in the symposium were compared against the intervention group. Thirteen students participated in the educational symposium. Hundred and nine students completed the general survey. In the non-intervention group, students demonstrated knowledge and confidence improvements through the second year of medical school but did not show similar improvement in subsequent years. No difference in MSK confidence scores between fourth-year students going into high versus low MSK focused specialities was observed. In the intervention group students demonstrated improvements in confidence with respect to the knee, shoulder and ankle exams (p < 0.01). Areas not covered such as concussions and neuromuscular impairments failed to show significant change. Current core clinical training, at least at our school, does not achieve satisfactory levels of knowledge and confidence with respect to caring for MSK conditions. However, a focused didactic and skill development intervention does produce significant improvements. Follow-up is needed to determine whether these improvements are sustained.

Articles from the anatomy, orthopaedic, and radiology literature since 1943 were reviewed, and possible sources of anterior ankle impingement were identified therein. There are both osseous and soft tissue causes of impingement symptoms. Anterior impingement in dancers may be induced by repetitive dorsiflexion during demi-plié, where the anterior edge of the distal tibial articular surface contacts the dorsal neck of the talus. It also can be associated with the sequelae of lateral ankle sprain, including a hypertrophic tissue response, or simply by impingement of anatomically normal ligamentous structures. Dance medicine clinicians should be familiar with the pathoanatomy and etiologies of this clinical entity in order to provide effective care for dancers who suffer from it.

The efficacy of methylprednisolone in the treatment of traumatic spinal cord injury is controversial. We examined the effect of methylprednisolone on regional spinal cord blood flow and attempted to determine whether recovery of electrophysiological function is dependent on reperfusion, either during sustained spinal cord compression or after decompression. The effects of methylprednisolone therapy on recovery of somatosensory evoked potentials and on spinal cord blood flow were examined in a canine model of dynamic spinal cord compression. Methylprednisolone (30 mg/kg intravenous loading dose followed by 5.4 mg/kg/hr intravenous infusion) or saline solution was administered to thirty-six beagles (eighteen in each group) five minutes after cessation of dynamic spinal cord compression and loss of all somatosensory evoked potentials. After ninety minutes of sustained compression, the spinal cords were decompressed. Somatosensory evoked potentials and spinal cord blood flow were evaluated throughout the period of sustained compression and for three hours after decompression. Seven dogs treated with methylprednisolone and none treated with saline solution recovered measurable somatosensory evoked potentials during sustained compression. After decompression, three more dogs treated with methylprednisolone and seven dogs treated with saline solution recovered somatosensory evoked potentials. Four dogs treated with methylprednisolone lost their previously measurable somatosensory evoked potentials. In the methylprednisolone group, spinal cord blood flow was significantly higher (p < 0.05) in the dogs that had recovered somatosensory evoked potentials than it was in the dogs that had not. Reperfusion blood flow was significantly higher (p < 0.05) in the saline-solution group than it was in the methylprednisolone group. Spinal cord blood flow in the saline-solution group returned to baseline levels within five minutes after decompression. It did not return to baseline levels in the dogs treated with methylprednisolone. The methylprednisolone administered in this study did not provide a large or significant lasting benefit with regard to neurological preservation or restoration. Methylprednisolone may reduce regional spinal cord blood flow through mechanisms affecting normal autoregulatory blood-flow function.