Both total hip and knee arthroplasty have demonstrated outstanding clinical results. The functional spinal unit composed of the intervertebral disc and facet joints is at least as complex. The intricacies of the coupled motions of the functional spinal unit have made development of an artificial disc a challenge. There have been several failed attempts to create a disc replacement that recapitulates normal motion while providing significant longevity and a low incidence of complications. Better understanding of the biomechanics of the intervertebral disc complex and improvements in implant material have made successful intervertebral disc replacement a likely reality, now that several artificial discs have completed Food and Drug Administration clinical trials. In this manuscript the authors detail the biomaterials used in disc arthroplasty and discuss joint wear and the host response to wear debris.