DUMMY DEVICE FOR MOULDING BONE CAVITY FORM

摘要

There is disclosed a dummy device for moulding a bone cavity form, and a method of manufacture of a prosthetic device to be implanted in any given bone cavity and derived from the moulded dummy form. The moulded form corresponds at least partly with the shape of a bone cavity (12, 16, 14), which is to receive a prosthetic joint, with the cavity having an enlarged proximal end (12) and a narrower distal end (14), and the moulded form enabling the required profile of the prosthetic joint to be derived therefrom in order to be implanted in the bone cavity. The method uses a model (10) having a preformed proximal dummy portion (11) to fit in the proximal end (12) of the bone cavity, a distal end portion (13) to be received by the distal end (14) of the cavity, and a bag (15) to enclose at least the dummy head portion (11) of the model. After introduction of the model into the bone cavity, the space between the outer surface of the dummy portion (11) and the inner surface of the bag (15) is filled with a moulding composition which expends the bag into intimate contact with the wall surface of the cavity in the proximal end portion (12), and this composition is then allowed to set, after which the moulded form is removed from the cavity to form a moulded model from which the required profile of the prosthetic joint can be derived by following the external shape of the moulded model (22) with a profile detector (21) and causing a machine to shape the outer profile of a prosthetic joint (24) with a corresponding shape so that the prosthetic joint can be implanted into the bone cavity.