Abstract: The present invention discloses an apparatus for delivering bio-active substances to specified sites of action in the course of performing surgical procedures and particularly of performing surgical procedures requiring reconstructive orthopaedic intervention. It further relates to referred constructions of such apparatus so that it is best adapted for use in the performance of surgical procedures requiring reconstructive orthopaedic intervention, especially high tibial osteotomies and mandibular, or other skull bone, reconstructions. Additionally disclosed is a method for implanting an apparatus according to the invention, as well as a method for performing tibial osteotomies using the apparatus of the invention.