Studies in chickens show that blood levels of a particular form of vitamin D (called 24,25-dihydroxvitamin D) increase after bone fracture. Laboratory studies show that this form of vitamin D helps the bone healing process in chickens. The investigators want to find out whether blood levels of this form of vitamin D increase after bone fracture in humans. Previous research studies have not addressed this question. The results of this research could eventually lead to the development of new treatments to help bone healing after fracture.