A Protective cover for an acetabular component
Publication Date: 2008-May-14
The IP.com Prior Art Database
A protective cover for fitting to the acetabular cup component of a hip joint prosthesis includes a flange which can be fitted to the open edge of the cup component so that it extends beyond the edge of the cup component to control the flow of bone cement from the external surface of the cup component. A protrusion extends from the flange to contact the internal bearing surface of the cup component and has a rounded surface at its end at which it contacts the bearing surface.
A PROTECTIVE COVER FOR AN ACETABULAR CUP COMPONENT
This invention relates to a protective cover for fitting to the acetabular cup component of a hip joint prosthesis.
A hip replacement procedure involves preparing the acetabulum to receive a cup component of a hip joint prosthesis. The cup component has an outer surface to engage the prepared surface of the acetabulum and an inner surface which can receive the head of the femoral component of the prosthesis. The cup component can be formed from a metal (such as titanium and its alloys, certain stainless steels and certain cobalt-chromium- molybdenum alloys) or a polymeric component such as an ultrahigh molecular weight polyethylene.
In cemented procedures, a bone cement is used to bond the component to the bone tissue of the prepared acetabulum. In contrast, in a cementless procedure, the acetabular component can be fixed in place in the acetabulum by direct interaction between the bone and the surface of the component. This can be facilitated by providing the component with a porous outer surface which facilitates ingrowth of bone tissue.
It is desirable to protect the internal surface of an acetabular cup component during a hip replacement procedure, especially when the surface has been prepared to engage directly the bearing surface of the head of a femoral component. For example, it is desirable to prevent bone cement which is used to fix the cup component in the acetabulum from coming into contact with the cup component bearing surface. It is also desirable to prevent scratches on the cup component bearing surface during the course of the procedure.
It can also be desirable to apply force to an acetabular cup component when it is implanted into a patient's acetabulum, especially when the cup component is to be fixed in place using a bone cement. The application of force can facilitate the formation of a secure bond between the cup component and the tissue of the acetabulum.
US-6019766 discloses an acetabular cup cement pressurisation device which has an outer rim which can be fitted to a cup component. The device has features which enable it to be engaged by an insertion tool so that the device and the cup component can be manipulated using the tool. An insertion force that is applied using the insertion tool is applied through the rim of the cup component.
The present invention provides a protective cover for fitting to the acetabular cup component of a hip joint prosthesis, which includes a protrusion which extends inwardly from a flange to contact the internal bearing surface of the cup component and which has a rounded surface at its end at which it contacts the bearing surface.
Accordingly, in one aspect, the invention provides a protective cover for fitting to the acetabular cup component of a hip joint prosthesis, which comprises:
a. a flange which can be fitted to the open edge of the cup component so that...