An arrangement for the preparation of the proximal surface of the tibia for a tibial component of a prosthetic knee joint, said arrangement including; a tibial and femoral stability gap preparation plate, said tibial and femoral stability gap preparation plate adapted to be placed upon an initially resected proximal surface of the tibia, said tibial and femoral stability gap preparation plate further including an upper side, said upper side having a plurality of user operable height adjustable extension tabs (22a-d), wherein each user operable height adjustable extension tab is adapted to engage an underside of a joint liner, wherein said joint liner includes an upper articulated surface to engage a femoral component of a prosthetic knee joint, such that a height adjustment of said plurality of user operable height adjustable extension tabs defines a stability gap, said defined stability gap provides a stable balanced complete angular movement between a tibial component and a femoral component of the prosthetic knee joint throughout an arc of motion from extension, mid-flexion and flexion; characterized in that the arrangement further includes: a stability gap guide drill plate place-able upon the initially resected proximal surface of the tibia subsequent to a withdrawal of the tibial and femoral stability gap preparation plate, said stability gap guide drill plate characterised by including a series of apertures (74a-d) configured to overlap with locations of the corresponding plurality of user operable height adjustable extension tabs when the tibial and femoral stability gap preparation plate was placed upon the initially resected proximal surface of the tibia, said series of apertures adapted to act as a guide for a drill bit to drill a series of bore holes into the proximal surface of the tibia to a depth commensurate with the height adjustment of the user operable height adjustable extension tabs; a stability gap router plate place-able upon the proximal surface of the tibia subsequent to the withdrawal of the stability gap guide drill plate, said stability gap router plate including a series of vertical mounts adapted to be secured within the series of bore holes drilled into the proximal surface of the tibia to the depth commensurate with the height adjustment of the user operable height adjustable extension tabs such that when the series of vertical mounts are secured within the series of bore holes the stability gap router plate is adapted to allow a router to complete a final bone resection on the surface of the tibia to rout or cut away bone about each of the series of bore holes down to a depth of each of the series of bore holes. a stability gap guide drill plate place-able upon the initially resected proximal surface of the tibia subsequent to a withdrawal of the tibial and femoral stability gap preparation plate, said stability gap guide drill plate characterised by including a series of apertures (74a-d) configured to overlap with locations of the corresponding plurality of user operable height adjustable extension tabs when the tibial and femoral stability gap preparation plate was placed upon the initially resected proximal surface of the tibia, said series of apertures adapted to act as a guide for a drill bit to drill a series of bore holes into the proximal surface of the tibia to a depth commensurate with the height adjustment of the user operable height adjustable extension tabs; a stability gap router plate place-able upon the proximal surface of the tibia subsequent to the withdrawal of the stability gap guide drill plate, said stability gap router plate including a series of vertical mounts adapted to be secured within the series of bore holes drilled into the proximal surface of the tibia to the depth commensurate with the height adjustment of the user operable height adjustable extension tabs such that when the series of vertical mounts are secured within the series of bore holes the stability gap router plate is adapted to allow a router to complete a final bone resection on the surface of the tibia to rout or cut away bone about each of the series of bore holes down to a depth of each of the series of bore holes.