Variable offset reamer assembly for modular humeral component

An instrument kit for reaming a surface of a resected head of a bone, the bone having a cavity extending into the bone from the surface, the kit comprising:

• a reaming guide comprising an elongate stem portion insertable into the cavity, the reaming guide comprising a neck portion having a reference formation and a flange, the flange arranged to limit insertion of the reaming guide into the cavity such that at least a portion of the neck portion extends from the surface of the bone;
• at least two adapter sleeves mountable upon the reaming guide, each adapter sleeve having a longitudinal axis, being generally cylindrical, and having a bore configured to receive part of the neck portion of the reaming guide, the axis of the bore being parallel to the longitudinal axis of the adapter sleeve defined by the cylindrical outer surface, the distance between the axis of the bore and the longitudinal axis of the adapter sleeve differing for each adapter sleeve, each adapter sleeve further comprising a collar arranged to engage the reference formation to prevent rotation of such adapter sleeve about the neck portion of the reaming guide;
• and
• a reamer comprising a central bore arranged to be disposed about the outer surface of at least one of the at least two adapter sleeves and a reaming head extending around the central bore;
• wherein, when the adapter sleeve is mounted upon the neck portion of the reaming guide inserted into the cavity, the reamer is arranged to ream the surface of the bone around the neck portion.