Prothesis for an Artificial Joint Having a Wear Particle Collection Capability

A significant problem encountered in present day artificial joints is the creation of wear particles which cause inflammation, cyst formation and joint loosening. Such problems heretofore have only been resolved by resorting to additional surgery.

The present invention has as its objective a prosthesis feature which permits wear particles created during the use of artificial joints to be displaced from the joint area. This is accomplished by providing in the prosthesis itself one or more relief passages through which joint fluids can circulate. The passages are designed such that wear particles carried by the fluid are deposited within the prosthesis itself at a location where the particles cannot cause inflammation, cyst formation or joint loosening. Alternatively, in a preferred embodiment of the invention, means are provided at accessible sites in the passages for collecting the particles so that by percutaneous access to the site, a needle, under x-ray image control, can withdraw the collected particles.

The invention now will be described in greater detail by reference to the accompanying drawing, FIG. 1, an elevational view illustrating a conventional hip prosthesis which has been modified to incorporate the invention.

Although a hip prosthesis is utilized in describing the invention, it will be understood that the same features employed for collecting wear particles in such a prosthesis can be incorporated in other artificial joints such as those used in knee, shoulder, elbow and ankle surgery, or the like.

Referring to FIG. 1, a conventional hip prosthesis 10 is provided in the proximal portion of its femoral stem 12 with openings 14 and 16 which communicate to form a passage 18 having a particle-receiving chamber 19. The openings are located such that with the prosthesis positioned within the body, joint fluid can enter the holes and circulate through the passage. The orientation of the openings is such that as wear particles are created in the joint, they are carried through the passage and are deposited, by gravity, at the lowermost portion of the chamber 19. Periodically, under x-ray image control, a needle can be inserted within an opening so as to withdraw particles which have been so deposited in the chamber.

To further facilitate collection of wear particles, the passage can be provided with a filter material 20 at a convenient location. Alternatively, in the case of a magnetizable metal prosthesis, a selected area of the passage can be magnetized to provide a collection site for particles separated from the prosthesis through wear. The invention also contemplates the use of a chemical material within the passage having an affinity for the wear particles so as to collect them within the chamber 19.

It will be understood that the channel openings formed in various prostheses can be provided at any convenient location so long as they are accessible to the source of the wear particles.