With modern orthopaedic surgical care, rates of complications following tibia and femoral shaft fractures can be as high as 15%. Complications, including delayed union, nonunion, or infection often require secondary surgical procedures and result in profound personal and societal economic costs. While surgeons continue to seek advances in surgical technique, it is becoming increasingly obvious that innovations in orthopaedic techniques or implants are unlikely to eliminate complications. As a result, considerable attention is currently focused on adjunct biologic therapies, such as vitamin D.