Other

Derek S Porritt

A Seth Greenwald

Mary-Blair Matejczyk

Nathaniel C Narten

Steven P Combs

Jack M Geiger

John J Brems

The suction lavage system of this invention incorporates a pulsatile water lavage in combination with a suction system to improve the interface between a prosthesis, such as a hip replacement, and the interdigitating network of cancellous bone in which it is secured with acrylic cement. The water lavage effectively evacuates the medullary fat and hematopoietic tissue from the trabecular interstices of cancellous bone. The suction irrigation system comprises a probe having two configurations which assist in impinging water on cancellous bone for evacuating fat and tissue along with water to improve the interface between the bone and cement. It has been found that weakening of the interface through stress may result in loosening of a prosthesis. The probe consists of a water conduit generally located on the outside of a suction conduit. The suction opening is located below the aperture for the pulsatile jet a distance large enough to insure that the apertures are not immersed in irrigating fluid; the apertures may be displaced to the side or down, or some combination of the two. The water jet pulses at about 2100 pulses per minute. In order to operate to maximum advantage, the pulsatile jet must function in an air environment. This is insured by the fact that the suction outflow is greater than the fluid inflow. The method of this invention, then, relates to preparing cancellous bone to secure a prosthesis, which is achieved by reaming out of the cancellous bone to fit the prosthesis; suction lavaging the cavity with a probe which includes a pulsatile jet of water to evacuate the water, fat and tissue; and securing the acrylic bone cement to the prepared cancellous surface. In the method of this invention, it is possible to increase the interface shear strength of the lavaged preparation by 162%, which is significant in terms of a control which normally uses saline solution.

Method of suction lavage

A prosthetic joint of the type used to replace dysfunctional non-weight bearing joints such as the knuckle, wrist, elbow or shoulder. The preferred embodiment comprises a radial component connected by a concavo-convex socket component to a metacarpal component. The radial component has an intramedullary stem terminating in a cup having a plurality of inwardly extending pins. The concavo-convex socket component is retained in the cup by the articulation of the pins with a plurality of flats which communicate with slots which terminate in apertures. The concavo-convex component includes an opening extending inwardly from one end thereof which defines two communicating bearing surfaces, with the innermost surface being spherical and the outer surface being frusto-conical and having an elliptical cross-section. The metacarpal component includes a ball, a neck area and an intramedullary stem. The ball articulates with the spherical surface of the concavo-convex member component and the neck, which also has an elliptical cross-section, articulates with the frusto-conical surface. The intramedullary stem which is connected to the cup is offset volarly by an amount equal to the offset in the metacarpal component thereby providing a greater moment arm for the weaker tendons of the wrist.

Endoprosthetic bone joint

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Medina, OH, United States of America

Derek S Porritt