Spinal facet implants with mating articulating bearing surface and methods of use

A method for replacing at least one facet of a first vertebra of a spine, the method comprising:

• resecting the first vertebra to provide a resected portion of the first vertebra;
• and
• attaching a coupling portion of a prosthesis to the first resected portion to position an articulating surface of the prosthesis to articulate against an articulating surface of a second vertebra;
• wherein positioning the articulating surface of the prosthesis comprises providing a medial-lateral range of relative motion between the first and second vertebrae that decreases significantly with extension of the spine.

A method for replacing at least one facet of a first vertebra of a spine, the method comprising:

• resecting the first vertebra to provide a resected portion of the first vertebra;
• and
• attaching a coupling portion of a prosthesis to the resected portion to position an articulating surface of the prosthesis to articulate against a second articulating surface of a second vertebra;
• wherein the articulating surface of the vertebra comprises a cephalad end and a caudal end and a radius of curvature about an axis extending generally from the cephalad end to the caudal end, wherein positioning the articulating surface of the prosthesis comprises significantly inclining the axis anteriorly toward the cephalad end.