Smith + Nephew

Smith & Nephew Orthopaedics Ag

Smith & Newphew Plc

Richemont International S.a.

Lorenz Brunner

Shilesh C Jani

Yvo Dirix

Vivek Devidas Pawar

Mark Lee Morrison

Paul Smith

Robert Scadding Moir

Hans F Schmotzer

Theo Tervoort

Roberto Tommasini

David Giger

Jonathan Sander

Stephen Sams

Richard Thomas Bown

Mark L Morrison

Oxidation resistant crosslinked ultrahigh molecular weight polyethylene (UHMWPE) is described, wherein at least two different additives in the manufacture synergistically increase the oxidation resistance of crosslinked UHMWPE. This allows the manufacture of oxidation resistant crosslinked UHMWPE using lower levels of additives and/or lower levels of crosslinking irradiation or chemicals. The lower levels of additives and/or crosslinking produce crosslinked UHMWPE having desired physical properties not possible without the synergistic interaction of the additives. This crosslinked UHMWPE may be used in medical prostheses such as in bearing components having desired physical properties such as wear resistance and oxidation resistance not possible without the synergistic interaction of the additives.

Synergistic effects on blending multiple additives in UHMWPE

Synergistic effects of blending multiple additives in UHMWPE

Provided are processes comprising crosslinking polyethylene or using crosslinked polyethylene. Furthermore, the processes may include compacting and/or sintering the polyethylene. The polyethylene can comprise virgin ultrahigh molecular weight polyethylene having a weight average molecular weight of at least 1,000,000 g/mol, to provide a compacted composition comprising virgin ultrahigh molecular weight polyethylene.

Processes comprising crosslinking polyethylene or using crosslinked polyethylene

The present invention relates to highly cross-linked UHMWPE, which is possessed of an improved oxidation resistance, as well as a method for making the same. The UHMWPE material of the current invention is combined with an anti-oxidant compound or a free-radical scavenger prior to formation. Once the UHMWPE with the added material has been formed and treated with gamma or electron bean irradiation, it shows an improved wear resistance and also a good resistance to oxidation. Such a material, is particularly interesting for the field of making replacement joint implants.

Oxidation resistant highly-crosslinked UHMWPE

A prosthetic device may comprise an insert having a first surface configured to contact a first prosthetic component and a bearing surface configured to articulate against a second prosthetic component. The insert comprises an ultra-high molecular weight polyethylene and vitamin E. The vitamin E may have a concentration in the range of 0.02 to 0.12 wt % first mixed with the ultra-high molecular weight polyethylene and then molded with the ultra-high molecular weight polyethylene at a temperature greater than the melting point of the ultra-high molecular weight polyethylene. The ultra-high molecular weight polyethylene and vitamin E may be gamma irradiated with a dosage of radiation between 5 and 20 Mrad. The insert may be machined prior to gamma irradiating the insert in air such that the gamma irradiation, at suitably high dosages, may also sterilize the insert.

Ultra high molecular weight polyethylene for bearing surfaces

A substance, which contains anti-inflammatory substances, anti-microbial substances, anti-tumor substances, anti-viral substances, and/or bone stimulating substances, as an additive, can be added to an UHMWPE material for the production of a medical implant for imparting benign body response properties to the medical implant.

UHMWPE medical implant producing wear particles with benign body response

A method for obtaining a composition of at least two components, comprising the steps of: providing at least one first fluid component; providing at least one second solid component and processing it so that the first component can diffuse into the second component; and diffusing the first component into the second component. A composition prepared by such a method.

Compositions and methods of making compositions

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Zurich, Switzerland

Lorenz Brunner