Cutting guide assembly

A cutting guide assembly for resecting a head of a bone, comprising:

• an elongate support rod configured to be partially disposed in and rotatable within a cavity extending into the head of the bone, the support rod defining a longitudinal axis;
• and a first cutting plate and a second cutting plate, each of the first cutting plate and the second cutting plate separately couplable to the support rod, the first cutting plate defining a first cutting surface and the second cutting plate defining a second cutting surface, the first cutting plate and the second cutting plate arranged such that, when either the first cutting plate or the second cutting plate is coupled to the support rod, the bone can be cut to form a resection surface by aligning a cutting tool with the first cutting surface or the second cutting surface;
• wherein the first cutting plate, when coupled to the support rod, is located at a first position offset laterally from the longitudinal axis, and the second cutting plate, when coupled to the support rod, is located at a second position offset laterally from the longitudinal axis, the second position being offset radially from the first position, and in either case, the first cutting plate and the second cutting plate are oriented such that the bone can be cut to form the same resection surface, without rotating the support rod.