573 patients included a randomized trial to compare two methods of surgical fixation for femoral neck fractures in the elderly were also included in this observational study to determine the proportion of patients taking vitamin D supplementation and its effects on physical function and reoperation rate. Patients were categorized into 3 cohorts; non-users (did not take vitamin D supplementation), inconsistent vitamin D supplementation users (1-2 visits), and consistent vitamin D supplementation users (3-4 visits). Results indicated that less than half of the patients reported consistently using vitamin D supplementation. Consistent vitamin D supplementation was associated with an improved physical function (2.42 points on SF-12), but was not associated with rate of reoperation.