Method and apparatus for performing an open wedge, high tibial osteotomy

Apparatus for performing an open wedge, high tibial osteotomy, the apparatus comprising:

• a fixation screw having a head and integral shaft for securing an implant to the tibia, the fixation screw wherein
• the head has a continuous, generally cylindrical outer circumferential surface with at least one longitudinally arranged recess extending inwardly from the generally cylindrical outer circumferential surface, and at least one protrusion, extending outwardly from the generally cylindrical outer circumferential surface, wherein said recess is defined by being wholly within a circumference of said generally cylindrical outer circumferential surface and the at least one circumferentially located protrusion resiliently deforms;
• and
• the shaft has a distal threaded portion and a proximal threaded portion, wherein the distal threaded portion and the proximal threaded portion are characterized by different thread pitches.

Apparatus for performing an open wedge, high tibial osteotomy, the apparatus comprising:

• a fixation screw having a head and integral shaft for securing an implant to the tibia, the fixation screw wherein
• the head has a continuous, generally cylindrical outer circumferential surface with at least one longitudinally arranged recess, located on the generally cylindrical outer circumferential surface, and at least one protrusion, located on the generally cylindrical outer circumferential surface and adjacent the at least one recess to provide resilient deformation of the at least one protrusion, wherein said recess is defined by being wholly within said circumference and said protrusion extends outwardly from said circumference and the at least one circumferentially located protrusion resiliently deforms;
• and
• the shaft has a distal threaded portion and a proximal threaded portion, wherein the distal threaded portion and the proximal threaded portion are characterized by different thread heights.

Apparatus for performing an open wedge, high tibial osteotomy, the apparatus comprising:

• a wedge-shaped implant for disposition in a wedge-shaped opening created in the tibia, wherein the wedge-shaped implant comprises:
• an upper surface;
• a lower surface;
• at least one key, wherein the key comprises an outwardly directed surface that extends from at least one of the upper and lower surfaces and is configured to seat within a correspondingly formed keyhole within the tibia;
• and
• a bore hole extending through the at least one key for receiving a fixation screw in an angularly upward or downward direction;
• a discrete fixation screw for extending through the bore hole and securing the wedge-shaped implant to the tibia comprising a fixation screw head and integral threaded shaft, wherein the fixation screw head has an outer surface with at least one outwardly directed radial protrusion and at least one inwardly directed radial recess adjacent to the protrusion;
• and
• a locking mechanism for releasably locking the fixation screw to the wedge-shaped implant, wherein the locking mechanism comprises a detent formed within a circumference of the bore hole of the wedge-shaped implant and the protrusion formed on the fixation screw, such that the protrusion is capable of being seated in the detent if the fixation screw is advanced through the wedge-shaped implant.