Howmedica Osteonics Corporation

Aaron Essner

Aiguo Wang

Shi-Shen Yau

John H Dumbleton

Alfred J Zarnowski

Robert W Klein

Scott G Logan

Anthony Patrick Napolitano

A prosthetic knee implant system includes a prosthetic femoral component and a prosthetic tibial component. The femoral component includes a lateral condyle, a medial condyle, a bone-contacting surface that may be formed of porous metal, and an articular surface that may be formed of PAEK/PEEK. The tibial component includes medial and lateral condylar portions, a bone-contacting surface that may be formed of porous metal, and a second surface opposite the bone-contacting surface. Recesses extend a depth into the second surfaces of the medial and lateral condylar portions. Medial and lateral bearing inserts with flat proximal faces are positioned with the recesses of the medial and lateral condylar portions. Flexible medial and lateral meniscal components are positioned to surround the medial and lateral inserts, respectively, and extend proximal to the second surface of the insert.

Patient specific composite knee replacement

A method of producing an improved polyethylene, especially an ultra-high molecular weight polyethylene utilizes a sequential irradiation and annealing process to form a highly cross-linked polyethylene material. The use of sequential irradiation followed by sequential annealing after each irradiation allows each dose of irradiation in the series of doses to be relatively low while achieving a total dose which is sufficiently high to cross-link the material. The process may either be applied to a preformed material such as a rod or bar or sheet made from polyethylene resin or may be applied to a finished polyethylene part.

Sequentially cross-linked polyethylene

One embodiment of the implant comprises a porous metal bone ingrowth portion () having a first side connected to a high density or solid (fully dense) metal portion () which in turn has an opposite side connected to a porous metal soft tissue ingrowth portion () thus forming a sandwich structure with the high density or fully dense portion in the middle. The implant may be made of a resorbable material such as an alloy of magnesium. Alternately, the alloy can be selected from the group consisting of calcium, iron, yttrium and lithium. The porous metal soft tissue ingrowth portion () has porosity characteristics allowing cartilage to interdigitate with the pores and extend outwardly beyond the platform of the metal surface towards a joint capsule. The solid or fully dense intermediate layermay have some porosity, however that porosity prevents either bone tissue or cartilage tissue from migrating therethrough.

Platform for soft tissue attachment

A method of producing an improved polyethylene, especially an ultra-high molecular weight polyethylene utilizes a sequential irradiation and annealing process to form a highly cross-linked polyethylene material. The use of sequential irradiation followed by sequential annealing after each irradiation allows each dose of irradiation in the series of doses to be relatively low while achieving a total dose which is sufficiently high to cross-link the material. The process may either be applied to a preformed material such as a rod or bar or sheet made from polyethylene resin or may be applied to a finished polyethylene part. If applied to a finished polyethylene part, the irradiation and annealing must be accomplished with the polyethylene material not in contact with oxygen at a concentration greater than 1% oxygen volume by volume. When applied to a preform, such as a rod, the annealing of the bulk polymer part of the rod from which the finished part is made must take place on the rod before the implant is machined therefrom and exposed to oxygen.

A prosthetic medical device exhibiting improved wear resistance is fabricated by sealing at least one polyolefinic material in an airtight container and providing an inert atmosphere within the airtight container. The polyolefinic material is exposed to an irradiation source to yield a cross-linked irradiated polyolefinic material. At least one non-irradiated polyolefinic material is blended with the irradiated polyolefinic material, and the prosthetic medical device is formed from the blended material. Selectively cross-linked polymeric compositions may be created by blending a specific amount of cross-linked resins with a specific amount of uncross-linked resins then cured into a polymeric matrix whereby the desired degree or percentage of overall cross-linking is obtained. The polymeric material may then be formed directly into a finished article by injection molding the polymeric material.

Methods of improving the wear resistance of prosthetic medical devices

A prosthetic medical device exhibiting improved wear resistance is fabricated by irradiating at least one polyolefinic material in the presence of an inert atmosphere to yield a cross-linked irradiated polyolefinic material; blending at least one non-irradiated polyolefinic material with the at least one irradiated polyolefinic material, and forming the prosthetic medical device from the blended material. Selectively cross-linked polymeric compositions may be created by blending a specific amount of cross-linked resins with a specific amount of uncross-linked resins then cured into a polymeric matrix whereby the desired degree or percentage of overall cross-linking is obtained. The polymeric material may then be formed directly into a finished article by injection molding the polymeric material.

An improved prosthetic medical device having improved wear resistance and toughness is provided in the present application. A method is provided to selectively cross-link the polymeric matrix comprising the medical device by employing an interrupting means such as a mask, wire mesh or chopper wheel placed in between the medical device and irradiation source. In addition, the medical device may be translated while being irradiated to further effect the selective cross-linking. The present invention also provides for an injection molding process wherein a prosthetic medical device is formed in a single step, then selectively cross-linked.

Methods for preparing selectively cross-linked polyethylene orthopedic devices

Process for preparing selectively cross-linked polyethylene orthopedic devices

Methods for fabricating prosthetic medical devices exhibiting improved wear resistance include selectively cross-linking polymeric resins then curing and shaping the polymer into a finished article. Selectively cross-linked polymeric compositions may be created by blending a specific amount of cross-linked resins with a specific amount of uncross-linked resins then cured into a polymeric matrix whereby the desired degree or percentage of overall cross-linking is obtained. The polymeric material may then be formed directly into a finished article by injection molding the polymeric material.

Methods and compositions for fabricating prosthetic medical devices exhibiting improved wear resistance include selectively cross-linking polymeric resins then curing and shaping the polymer into a finished article. The selectively cross-linked polymeric compositions may be created by blending a specific amount of cross-linked resins with a specific amount of uncross-linked resins then cured into a polymeric matrix whereby the desired degree or percentage of overall cross-linking is obtained. The polymeric material may then be formed directly into a finished article by injection molding the polymeric material.

Growing community of inventors

Bloomingdale, NJ, United States of America

Aaron Essner