The present invention comprises a novel method and apparatus for performing an open wedge, high tibial osteotomy. More particularly, the present invention comprises the provision and use of a novel method and apparatus for forming an appropriate osteotomy cut into the upper portion of the tibia, manipulating the tibia so as to open an appropriate wedge-like opening in the tibia, and then mounting an appropriately-shaped implant at the wedge-like opening in the tibia, so as to stabilize the tibia with the desired orientation, whereby to reorient the lower portion of the tibia relative to the tibial plateau and hence adjust the manner in which load is transferred from the femur to the tibia.