An instrument for use in a joint replacement procedure comprises a head part which corresponds to the head of an orthopaedic joint component, in which the head part has a bore formed in it, and a connector for connecting the head part to a stem part of the orthopaedic joint component, which is intended for location in the intramedullary cavity of a bone. The connector can be fitted into the bore in the head part in one of a plurality of angular orientations. It comprises a body part and a trigger which can be moved relative to the body part between an unlocked position in which the connector can be moved relative to the head part between different ones of the plurality of angular orientations and a locked position in which the connector is restrained against such movement.