Despite extensive research aimed at improving surgical outcomes of enthesis injuries, re-tears remain a common problem, as the repairs often lead to fibrovascular scar as opposed to a zonal enthesis. Zonal enthesis formation involves anchoring collagen fibers, synthesizing proteoglycan-rich fibrocartilage, and mineralizing this fibrocartilage [1]. During development, the hedgehog signaling pathway promotes the formation and maturation of fibrocartilage within the zonal tendon-to-bone enthesis [1-4]. However, whether this pathway has a similar role in adult zonal tendon-to-bone repair is not known. Therefore, we developed a murine anterior cruciate ligament (ACL) reconstruction model [5] to better understand the zonal tendon-to-bone repair process and perturb key developmental regulators to determine the extent to which they can promote successful repair in the adult. In doing so, we activated the hedgehog signaling pathway both genetically using transgenic mice and pharmacologically via agonist injections. We demonstrated that both treatments improved the formation of zonal attachments and tunnel integration strength [6]. These improved outcomes were due in part to hedgehog signaling's positive role in proliferation of the bone marrow stromal cell (bMSC) progenitor pool and subsequent fibrocartilage production of bMSC progeny cells that form the attachments. These results suggest that, similar to growth and development, hedgehog signaling promotes the production and maturation of fibrocartilage during tendon-to-bone integration in adults. Lastly, we developed localized drug delivery systems to further improve the treatment of these debilitating injuries in future translational studies.

Acknowledgements: This work was supported by NIH R01AR076381, R21AR078429, R00AR067283, F31AR079840, T32AR007132, and P30AR069619, in addition to the McCabe Fund Pilot Award at the University of Pennsylvania.

Objective: To study potential predictors of functional outcome six months after the injury in elderly patients who sustained a hip fracture and who had been able to go out alone.

Design: Prospective Multi-center Cohort Study

Setting: 14 Hospitals in Japan

Patients and Methods: A cohort was consisted of 387 patients with a mean age of 81 who had a hip fracture, between December 2004 and January 2006. Inclusion criteria were that patients were at least sixty-five years old and who had been able to go out independently. Level of activity of daily living, medical complications, residential environment and family structure at injury was interviewed from the patient, the relatives and a nursing caretaker and recorded. Advancement of mobility was also recorded during the hospital stay. Patients were contacted or interviewed again by the investigator at six months following injury to assess functional outcomes. Primary outcome of interest was changes in mobility to go out independently at six months after injury.

Results: 178 patients (46%) lost their independency to go out at six month following surgery. Logistic multivariant regression showed that age, cognitive function, hemiplegia and mobile ability at discharge were the independent predictable factors for losing independency of mobility. At hospital discharge, T-cane walk was accomplished in only 53% for looser group but 86% for maintain group.

Conclusions: We believe that it would be the key factor to improve the mobility of the healthy patient with hip fracture that we lead them to T-cane walk before hospital discharge.