Freehand distal interlocking of intramedullary nails is technical demanding and prone to handling issues. It requires the surgeon to precisely place a screw through the nail under x-ray. If not performed accurately it can be a time consuming and radiation expensive procedure. The aims of this study were to assess construct and face validity of a new training device for distal interlocking of intramedullary nails. 53 participants (29 novices and 24 experts) were included. Construct validity was evaluated by comparing simulator metrics (number of x-rays, nail hole roundness, drill tip position and accuracy of the drilled hole) between experts and novices. Face validity was evaluated by means of a questionnaire concerning training potential and quality of simulated reality using a 7-point Likert scale (range 1-7). Mean realism of the training device was rated 6.3 (range 4-7) and mean training potential as well as need for distal interlocking training was rated 6.5 (range 5-7) with no significant differences between experts and novices, p≥0.236. All participants stated that the simulator is useful for