The FAITH trial evaluated sliding hip screw versus cancellous screws for the fixation of undisplaced femoral neck fractures in patients 50 years of age or older. The investigators have now completed a pilot study for FAITH-2, assessing a 2x2 design with similar operative options, as well as Vitamin D3 versus placebo. Over a 4-year-period, 91 patients were randomized and 86 included in the analysis. Feasibility criteria was not achieved due to low Vitamin D adherence, with only 55% of patients considered adherent. The feasibility of Vitamin D3 as an intervention was not demonstrated.