Arthroscopic suture bracing of posterior cruciate ligament in a multiple ligament knee injury - A technical report.

The optimum therapy of a torn PCL in multiligamental-injured knees is controversially discussed in literature. As conservative treatment and PCL reconstruction alone mostly lead to long-term immobilization, we performed a single stage PCL bracing with ACL reconstruction using ACL TightRopes® and Fiber-/TigerTapes® to accelerate back-to-sport after multiligamental knee injury with bicrucial tears. The brace consisted of two FiberTapes which were looped in an ACL TightRope and transosseously fixed with a Dog Bone-Button®. The ACL reconstruction was performed by a fourfolded semitendinosus graft in TightRope® technique. We chose an active rehabilitation-protocol with immediately allowed knee flexion to 90° in an ACL brace. This led to excellent results with resumption of sports after 6 months and good subjective and objective knee stability measured with a KT-1000. Our results hint that our method of bracing a torn PCL in multiligamental knee injuries may lead to faster rehabilitation with comparable knee stability.

5-Year imaging sequelae of concussive blast injury and relation to early clinical outcome.

Current imaging diagnostic techniques are often insensitive to the underlying pathological changes following mild traumatic brain injury (TBI) or concussion so much so that the explicit definition of these uncomplicated mild brain injuries includes the absence of radiological findings. In the US military, this is complicated by the natural tendency of service members to down play symptoms for fear of removal from their unit particularly in combat making it challenging for clinicians to definitively diagnose and determine course of treatment. Questions remain regarding the long-term impact of these war-time brain injuries. The objective of the current study was to evaluate the long-term imaging sequelae of blast concussion in active-duty US military and leverage previous longitudinal data collected in these same patients to identify predictors of sustained DTI signal change indicative of chronic neurodegeneration. In total, 50 blast TBI and 44 combat-deployed controls were evaluated at this 5-year follow up by advanced neuroimaging techniques including diffusion tensor imaging and quantitative volumetry. While cross-sectional analysis of regions of white matter on DTI images did not reveal significant differences across groups after statistical correction, an approach flexible to the heterogeneity of brain injury at the single-subject level identified 74% of the concussive blast TBI cohort to have reductions in fractional anisotropy indicative of chronic brain injury. Logistic regression leveraging clinical and demographic data collected in the acute/sub-acute and 1-year follow up to determine predictors of these long-term imaging changes determined that brain injury diagnosis, older age, verbal memory and verbal fluency best predicted the presence of DTI abnormalities 5 years post injury with an AUC of 0.78 indicating good prediction strength. These results provide supporting evidence for the evolution not resolution of this brain injury pathology, adding to the growing body of literature describing imaging signatures of chronic neurodegeneration even after mild TBI and concussion.

Patterning in time and space: HoxB cluster gene expression in the developing chick embryo.

The developing embryo is a paradigmatic model to study molecular mechanisms of time control in Biology. Hox genes are key players in the specification of tissue identity during embryo development and their expression is under strict temporal regulation. However, the molecular mechanisms underlying timely Hox activation in the early embryo remain unknown. This is hindered by the lack of a rigorous temporal framework of sequential Hox expression within a single cluster. Herein, a thorough characterization of HoxB cluster gene expression was performed over time and space in the early chick embryo. Clear temporal collinearity of HoxB cluster gene expression activation was observed. Spatial collinearity of HoxB expression was evidenced in different stages of development and in multiple tissues. Using embryo explant cultures we showed that HoxB2 is cyclically expressed in the rostral presomitic mesoderm with the same periodicity as somite formation, suggesting a link between timely tissue specification and somite formation. We foresee that the molecular framework herein provided will facilitate experimental approaches aimed at identifying the regulatory mechanisms underlying Hox expression in Time and Space.