Biocompatibility assessment of biomaterials used in orthopedic devices: An overview (Review)

Biocompatibility is one of the mandatory requirements for the clinical use of biomaterials in orthopedics. It refers to the ability of a biomaterial to perform its function without eliciting toxic or injurious effects on biological systems but producing an appropriate host response in a specific case. Today, the biocompatibility concept includes not only bio-inertia, but also biofunctionality and biostability. High biocompatibility and functional properties are highly desirable for new biomaterials. The chemical, mechanical, structural properties of biomaterials, their interaction with biological environment or even the methodology of assessment can influence the biocompatibility. The biological evaluation of biomaterials includes a broad spectrum of in vitro and in vivo tests related to the cytocompatibility, genotoxicity, sensitization, irritation, acute and chronic toxicity, hemocompatibility, reproductive and developmental toxicitity, carcinogenicity, implantation and degradation as specified in different international standards. A brief review of the main assays used in the biocompatibility testing of orthopedic biomaterials is presented. In addition, their main biocompatibility issues are overviewed.