Tardigrades are microscopic animals renowned for their ability to survive extreme desiccation. Unlike many desiccation-tolerant organisms that accumulate high levels of the disaccharide trehalose to protect themselves during drying, tardigrades accumulate little or undetectable levels. Using comparative metabolomics, we find that despite being enriched at low levels, trehalose is a key biomarker distinguishing hydration states of tardigrades. In vitro, naturally occurring stoichiometries of trehalose and CAHS proteins, intrinsically disordered proteins with known protective capabilities, were found to produce synergistic protective effects during desiccation. In vivo, this synergistic interaction is required for robust CAHS-mediated protection. This demonstrates that trehalose acts not only as a protectant, but also as a synergistic cosolute. Beyond desiccation tolerance, our study provides insights into how the solution environment tunes intrinsically disordered proteins’ functions, many of which are vital in biological contexts such as development and disease that are concomitant with large changes in intracellular chemistry.

Level III, retrospective comparative study.

Background: Charcot-Marie-Tooth (CMT) disease is a hereditary motor-sensory neuropathy that is often associated with a cavovarus foot deformity. Limited evidence exists for the orthopedic management of these patients. Our goal was to develop consensus guidelines based upon the clinical experiences and practices of an expert group of foot and ankle surgeons. Methods: Thirteen experienced, board-certified orthopedic foot and ankle surgeons and a neurologist specializing in CMT disease convened at a 1-day meeting. The group discussed clinical and surgical considerations based upon existing literature and individual experience. After extensive debate, conclusion statements were deemed “consensus” if 85% of the group were in agreement and “unanimous” if 100% were in support. Conclusions: The group defined consensus terminology, agreed upon standardized templates for history and physical examination, and recommended a comprehensive approach to surgery. Early in the course of the disease, an orthopedic foot and ankle surgeon should be part of the care team. This consensus statement by a team of experienced orthopedic foot and ankle surgeons provides a comprehensive approach to the management of CMT cavovarus deformity. Level of Evidence: Level V, expert opinion.

Level II, systematic review.

Background: The purpose of this systematic review is to examine the literature on Achilles tendon (AT) injuries in professional athletes to determine their rate of return to play (RTP), performance, and career outcome after AT rupture. Methods: A literature search of MEDLINE, Google Scholar, CINAHL, and Cochrane Library databases was performed. Included studies reported outcomes related to RTP (time and rate), durability and player participation, and player performance following AT rupture in professional athletes of the National Football League (NFL), National Basketball Association (NBA), Major League Baseball (MLB), and professional soccer leagues. Results: Fifteen studies met inclusion criteria for analysis. Athletes were able to return to professional sport participation 76% of the time, with mean time to RTP of 11 months following AT injury. Athletes experienced a decline in player efficiency ratings, power ratings, and sport- and position-specific statistics in the NFL, NBA, and professional soccer leagues compared to noninjured controls. RTP rate was significantly lower following AT rupture in comparison to athletes sustaining other common orthopaedic injuries such as anterior cruciate ligament injuries, meniscal tears, and ankle fractures in both NFL and NBA athletes. Conclusions: AT rupture prohibits nearly 25% of professional athletes from returning to their respective sport. Of those able to return to compete at a professional level, the mean time to RTP is 11 months—nearly double the estimated 6-month recovery for RTP in the general population. Furthermore, player performance and durability were curtailed following AT rupture. This review of the literature should be used to set evidence-based goals and establish realistic expectations for RTP for elite athletes following AT injuries. Level of Evidence: Level III, systematic review.