Johns Hopkins University

Amy A Corvelli

Paul J Biermann

Jack C Roberts

An orthopedic implant comprising a thermoplastic polymer or a composite comprising, in one embodiment, polyetheretherketone reinforced with 10% by volume of glass fibers, with an elastic modulus approximating the elastic modulus of bone. A porous coating is formed on the implant surface by creating a roughness thereon, by coating the surface with hydroxyapatite or by embedding a biocompatible material such as titanium in the surface. A two piece embodiment of the implant is joined and locked together, after the opposite ends of each piece are inserted in the medullary canal, using an interlocking mechanism comprising a fluted protrusion on one piece and a corresponding fluted cavity in the other piece with the fluted portions being complementarily tapered.

Polymeric composite orthopedic implant

Apparatus and methods for partially embedding a biocompatible material, such as a titanium coil, in the surface of a polymer bone implant to provide a porous coating for bone cells to grow through thereby promoting long term stabilization of the implant. In one embodiment, the coil is wrapped around the implant and placed in a manifold where rollers biased by springs press against the coil. The coil-implant is rotated and heated by a hot gas stream, the rollers-springs pushing the coil into the surface of the implant. In a second embodiment, the coil is compressed and placed onto a needle wire which is placed against the surface of the implant. The point of contact is heated and the implant is rotated with the needle wire creating a channel in the softened polymer and feeding the coil, which is simultaneously stretched, therein. The needle wire then pulls the polymer over a portion of the coil as it passes. In a third embodiment, the coil is wrapped around the implant with an optional titanium foil then wrapped around the coil-implant. A ceramic clamp comprising at least two ceramic parts is placed around the foil(if used)-coil-implant and held in place by a nonconductive, elastic material. The coil-implant is then inductively heated with the coil being pushed into the softened surface of the implant by the pressure applied by the ceramic parts being compressed together by the elastic material. Alternatively, the titanium coil may be wrapped around the implant in sufficient tension that it will embed itself when inductively heated, without using the ceramic clamp and elastic material to apply pressure.

Growing community of inventors

Columbia, MD, United States of America

Amy A Corvelli