Pulsed current sintering for surfaces of medical implants

Abstract

A porous medical implant and a method of making same is described. The medical implant comprises a porous surface formed by application of pulsed electrical energy ins such a way as to cause a localized heating in the surface of the material comprising portions of the implant. The method comprises a pulsed current sintering technique.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to U.S. provisional application Ser. No. 60 / 589,143, filed on Jul. 19, 2004.TECHNICAL FIELD [0002] The present invention is directed toward the fabrication of a porous sintered surface for medical implants. BACKGROUND OF THE INVENTION [0003] For a variety of reasons, it is sometimes necessary to surgically correct an earlier implanted medical implant (most commonly a prosthetic joint) or replace it with an entirely new medical implant. Typically, this results from either a loosening of the implant in the implant site, or the deterioration of the implant due to forces such as abrasion. Ideally, an medical implant is often formed from a high-strength material which is not only able to accommodate the various loading conditions that it may encounter, but is also non-toxic to, and otherwise biocompatible with, the human body. It is also preferable to implant the device in such a way as to enhance fixation ov...

AI Technical Summary

Benefits of technology

[0013] There is also a medical implant having a porous surface produced by the process comprising the steps of placing a finite number of non-spherical individual bodies in continuous contact with one another; and, sintering the individual bodies by applying pulsed electrical energy across at least a portion of the aggregate mass of the individual bodies, thereby creating a cohesive porous structure.

Problems solved by technology

Typically, this results from either a loosening of the implant in the implant site, or the deterioration of the implant due to forces such as abrasion.

Ideally, an medical implant is often formed from a high-strength material which is not only able to accommodate the various loading conditions that it may encounter, but is also non-toxic to, and otherwise biocompatible with, the human body.

While medical implant devices made from biocompatible metal alloys are effective, they may lack certain desirable characteristics.

For example, metal alloys have poor flexibility and therefore do not tend to distribute load as evenly as would be desired.

Uneven loads tend to result in a gradual loosening of the implant.

As such loosening becomes more severe, revision or replacement becomes necessary.

While such sintered surface imparts desirable porosity, sintering at such extreme conditions of temperature and time fundamentally alter the nature of the substrate in undesirable ways.

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