Instrument for use in a joint replacement procedure

The instrument of claim 2, wherein the lip is provided at the end of the arm.

A kit for use in a procedure for replacement of the head of a long bone in a joint replacement procedure, the long bone having an axis, comprising:

• a head component having a pole and an external surface in the form of part of a sphere which is truncated on a head component plane;
• an axial reference shaft configured to be arranged parallel to the axis of the long bone;
• a cutting guide movable relative to the axial reference shaft, the cutting guide comprising a reference block configured to be located against the bone relative to the lateral edge of the bone, and at least one arm shaped so that the at least one arm can extend from the cutting guide over the face of the head when the cutting guide is fastened to the lateral edge of the bone, wherein the arm can be located positively with respect to features on the head so that the location of the reference block along the axis of the bone can be set with reference to features on the head of the bone that are contacted by the arm, wherein the reference block defines a reference block plane and the arm defines an arm plane parallel to the reference block plane, and wherein the distance between the reference block plane and the arm plane is approximately equal to the distance between the pole of the head component and the head component plane.

A method of resecting the head of a long bone in a joint replacement procedure, further comprising the steps of:

• locating an instrument that includes an axial reference shaft relative to the long bone so that the shaft extends parallel to the axis of the bone;
• moving a cutting guide relative to the axial reference shaft, the cutting guide having a reference block for location against the bone relative to the lateral edge of the bone and at least one arm that is configured to extend from the cutting guide over the superior face of the head, so that the arm is located positively with respect to features on the head and so that the location of the reference block along the axis of the bone is set with reference to features on the head of the bone that are contacted by means of the arm.