Johnson & Johnson Professional, Inc.

Frank D Matthews

Michael J O'Neil

Salvatore Caldarise

Jorge A Ochoa

Robert C Hurlburt

Robert S Brown

Gerald J Cicierega

C M Jayashankar

An implant component adapted for bone attachment or replacement is molded from a feed stock which contains a soluble major binder, a backbone binder and structural powder material. After the feed stock is injection molded to form a compact or preform, the major binder is removed from the green article, leaving a structure of interconnected porosity or texture, while the backbone binder remains until the component is sintered. Preferably, the amount of the soluble binder is set to increase the porosity, or reduce the stiffness, of the finished component, thus introducing a biocompatible or growth-enhancing level of porosity or stiffness during the molding process. In further or alternative embodiments, the component may be injection molded onto or about a solvent-leachable spacer preform and/or adjacent to another injected or molded portion of the component which serves as a structural body, frame or shell. In these cases, all or a part of the molded portion may be formed with a conventional precision powder molding feed stock to achieve a high packing density/low shrinkage frame or support for the spacer preform or additional porous molding. The invention also includes constructions wherein the component body is injection molded against or about a support core or plate to form a hybrid article. The resulting implant component is unitized by the sintering process into a single article having the desired dimensions, strength and porosity.

Precision powder injection molded implant with preferentially leached

An augmentation system for an implantable bone prosthesis, such as a femoral component of a knee joint prosthesis, includes an augmenting block having an aperture disposed therein. A collet having an expandable distal end, extending beyond one surface of the augmenting block, is positioned within the aperture. The proximal end of the collet includes a cavity that receives an expansion pin that is adapted to communicate with the collet to expand the collet. The distal end of the collet is adapted to fit within a mounting cavity of a joint prosthesis. With the augmenting block placed on the appropriate surface of the joint prosthesis, the distal end of the collet is positioned within the mounting cavity. Advancement of the expansion pin causes the distal end of the collet to expand, thus frictionally and/or mechanically engaging the interior walls of the mounting cavity to firmly secure the augmenting system to the prosthesis. The expansion pin can include threads which mate with corresponding threads within the cavity of the collet. Alternatively, the pin and collet cavity can include ratchet and pawl-like surface features.

Joint prosthesis augmentation system

An orthopedic device is provided having a femoral stem with a proximal end, a distal end, and an intermediate portion extending between the proximal end and the distal end. The intermediate portion tapers from a first cross-sectional geometry near the proximal end to a second cross-sectional geometry near the distal end. A surface region of the femoral stem has a coefficient of friction less than 0.3 with respect to a bone cement. The surface region can include a treated metal region integral with the stem, or a friction reducing coating or sheath that coats or covers a portion of the stem. A collar can be provided near the proximal end of the stem that has a greater diameter than the first diameter of the stem.

Femoral stem with reduced coefficient of friction with respect to bone

A prosthetic hip joint includes a ceramic hip head having a bore which defines a surface, wherein the bore surface has a layer of malleable material disposed on at least a portion thereof. The surface of the bore includes surface imperfections in the form of peaks and valleys. The prosthetic hip joint can also include a femoral component having a trunnion with a tapered surface adapted for friction fit insertion into the bore of the hip head. The layer of material, such as pure titanium, distributes a load on the joint reducing localized stress points produced by opposing asperity peaks in the load-bearing surfaces of the bore and trunnion.

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Walpole, MA, United States of America

Frank D Matthews