An Orthopedic instrument serves as an adjustable guide for drills, reamers, fasteners, and other orthopedic devices which lie on a target line which extends from the lateral cortex of the femur, through an opening in the proximal end of an inserted intramedullary femoral nail, through the femoral neck, and into the femoral head. The instrument can be secured to and aligned with the inserted nail. A handle of the instrument extends downwardly from the top of the nail along a line which is substantially parallel to the target line. A guide arm is preferably slidably mounted on the handle and extends outwardly from the handle through the target line. At least one opening is formed through the guide arm coaxially with, or parallel to, the target line, for receiving a drill bit, guide tube, fastener, or similar device. When the instrument is used, for example, as a drill guide, the guide arm can be slidably adjusted along the handle to allow optimal positioning of the drill along.