Abstract: The invention concerns a tibial prosthetic component comprising a plate (100) for forming a tibial plateau of a tibia (16), wherein a peripheral region of the plate (100) has a thickness of less than 3 mm. The invention also concerns a tibial prosthetic component having a keel of depth less than 9 mm. The invention also concerns a method of selecting a tibial prosthetic component comprising receiving measurements of at least one physical attribute of an individual into whom the tibial prosthetic component is to be implanted, selecting a thickness of a plate (100) and depth of keel of the tibial prosthetic component based on the measurements and providing a tibial prosthetic component comprising a plate (100) having the selected thickness and a keel having the selected depth.

Abstract: A surgical instrument for aligning a surgical tool includes a tool guide in which is provided an opening for receiving and guiding a portion of the surgical tool and a bone engaging element which is adapted to engage a particular region of a bone.The bone engaging element has a bone engaging surface which has a known orientation relative to the opening in the tool guide. Consequently, when the bone engaging element engages the bone, the opening in the tool guide is correctly aligned with the bone. In a preferred embodiment, the instrumentation is adapted for resecting the distal end of a humerus and the bone engaging element engages the posterior cortex of the distal end of the humerus.

Abstract: There is described an acetabular cup having an outer shell and an inner liner, which inner liner provides a bearing surface of metallic or ceramic material, wherein there is provided in a position around the rim of the inner liner a shoulder formed of a material that is softer than that used for the head or neck of a femoral component with which the acetabular cup is to be used, which shoulder limits the motion of the femoral component during use. The shoulder may be of a polymeric material such as polyethylene. There is also described an acetabular cup having an inner liner of metallic of ceramic material and an outer shell which is manufactured from a bone cement material. There is further described a method of manufacturing the described acetabular cups which method comprises directly molding the polymeric shoulder of outer shell around the ceramic or metallic inner liner.