In one aspect, an intervertebral prosthetic device for implantation within a disc space between adjacent first and second vertebral endplates includes a body including a main body with an outer surface bearing portion configured to interface with and articulate relative to one of the first and second vertebral endplates. It also comprises an orientation protrusion shaped in a manner to at least partially inhibit rotation of the body in the disc space. The body is sized in at least one direction to fit inside a boundary defined by a travel path of the first vertebra relative to the second vertebra, the travel path forming an arc about a center of rotation of the first vertebra, the travel path being spaced from the center of rotation a distance substantially equivalent to the distance from the center of rotation to the second vertebral endplate.