Joint replacement surgery has become a common practice since it was started decades ago. It is one of the most successful field in joint surgery. However, due to changes in our population and changes in the prevalence of more degenerative joint diseases, the demand for more joint replacement is on the rise. As a consequence, more implant related problems such as loosening, dislocation, infection come along with it especially with the traditional materials used to produce them. With the emergent of nanotechnology, artificial implants that are based on the nano scale started emerging. But many have questioned the biocompatibility of these nano structure materials in vivo. This has warranted more research in medicine and other related fields. In this review, some of the biological responses that occur with nano-materials, and some of the biocompatibility problems that have been raised in relation to materials, as well as the ways that have been employed to improve biocompatibility of nano structure materials will be presented.