Synthetic Polymeric Materials for Bone Replacement

Some treatment options available to repair bone defects are the use of autogenous and allogeneic bone grafts. The drawback of the first one is the donor site's limitation and the need for a second operation on the same patient. In the allograft method, the problems are associated with transmitted diseases and high susceptibility to rejection. As an alternative to biological grafts, polymers can be used in bone repair. Some polymers used in the orthopedic field are poly(methyl methacrylate), poly(ether-ether-ketone), and ultra-high molecular weight polyethylene (UHMWPE). UHMWPE has drawn much attention since it combines low friction coefficient and high wear and impact resistance. However, UHMWPE is a bioinert material, which means that it does not interact with the bone tissue. UHMWPE composites and nanocomposites with hydroxyapatite (HA) are widely studied in the literature to mitigate these issues. HA is the main component of the inorganic phase in the natural bone, and the addition of this bioactive filler to the polymeric matrix aims to mimic bone composition. This brief review discusses some polymers used in orthopedic applications, focusing on the UHMWPE/HA composites as a potential bone substitute.