A newly developed family of ultrahigh molecular weight polyethylene (UHMWPE) incorporates small, highly reactive molecules that cross-link at significantly lower radiation doses than previous formulations. This capability minimises the adverse effects that radiation has on the polymer’s mechanical properties. It will enable the fabrication of stronger hip and knee implants with improved long-term stability. DSM Biomedical (Geleen, Netherlands) reportedly is the first company to apply this technique to UHMWPE.
This development is the result of an R&D program that DSM Biomedical initiated in 2007 to improve the properties of UHMWPE for use in artificial joints. Although the material has been used for more than 45 years in artificial joints, improvements in the material’s wear resistance are required to prevent revision surgeries. Cross-linking by means of high radiation doses significantly improves wear resistance, but it also affects the polymer’s mechanical properties.
“Nearly two million people receive artificial hips or knees each year, and the artificial joint market continues to grow in conjunction with trends associated with an aging population and increases in obesity,” says Leo Smit, Business Director for Implants, DSM Biomedical. “We believe that this platform will lead to more-stable implants and help reduce the number of revision surgeries needed.”
DSM Biomedical has filed a patent on this polymer platform and its application in total joint arthroplasty. Next up for DSM researchers is to optimise the polymer’s mechanical properties. DSM Biomedical expects to work closely with a number of major orthopaedic companies on the final development of the material.Norbert Sparrow