Elastomers for the development of orthopaedic implants : a review

Abstract

There has been an increase in the use of elastomers in the biomedical industry. Recent developments in utilising elastomers for use in orthopaedic implants has shown the great potential of these materials for long-term implantation. Elastomers are being developed for applications in tissue engineering, polymeric scaffolds and synthetic implants, all with the aim of repairing or maintaining orthopaedic joints in working order. The aim of this review is to discuss current developments in elastomeric orthopaedic implants and their most utilised materials namely silicones, polyurethanes and hydrogels. Polyurethane and silicone elastomers are commonly used in bulk implantable devices due to their good mechanical properties, chemical resistance and biocompatibility. Other materials such as polycarbonate urethanes (PCUs) are being utilised as means to protect the joints due to their superb mechanical properties and wear characteristics. The range of applications of elastomers vary from hip joint replacements, such as in the case of the TriboFit implant, meniscal implants, and first metatarsophalangeal joint replacements. More recently hydrogels have been utilised as coatings for increased lubrication in joint replacements, as a substitute for articular cartilage. Applications of hydrogels vary from improving the collagen and proteoglycan content of the joint to improving the load distribution across the joint in arthritic knee joints. The use of elastomers in orthopaedic implants is still in its infancy; and whilst a large amount of the research being done is still in the prototype stages, the potential of these materials and devices is unlimited.