Patent ID: 8152847

Claim:
A method of repair of articular cartilage comprising: locating articular cartilage having a lesion; utilizing an implant for repair of articular cartilage defects having dimensions compatible with the lesion, wherein the implant comprises: an articular end having a circular perimeter, a convex upper face, and a concave lower face, the convex upper face having a spherical radius and the concave lower face having a spherical radius; and a stem extending from the concave lower face away from the convex upper face along a vertical axis, the stem having a plurality of stem circular perimeters and a first stem portion having a maximum stem circular perimeter beginning at the intersection of the stem and the concave lower face and extending at least about one millimeter from the concave lower face along the vertical axis, the maximum stem circular perimeter having a diameter less than the articular end circular perimeter, the stem having second stem portion extending from the first stem portion away from the convex upper face along the vertical axis, the second stem portion having a plurality of second stem circular perimeters decreasing in diameter along at least one axis from the maximum circular perimeter of the first portion to a lesser second stem circular perimeter along the vertical axis of the stem; and wherein the stem has a plurality of circumferential grooves, wherein each circumferential groove extends continuously around at least one of the plurality of second stem circular perimeters, wherein at least one circumferential groove is defined between two adjacent second stem circular perimeters and has a shape of a partial torus extending radially inward of the adjacent second stem circular perimeters, wherein the at least one circumferential groove blends into at least one of the two adjacent second stem circular perimeters, wherein the stem blends into the concave lower face, and wherein the articular end and the stem each consist essentially of: a graphite core and a pyrocarbon coating forming a cavity in the articular cartilage, subchondral bone, and cancellous bone; and engaging the implant with the cavity so that the concave lower face abuts against the subchondral bone and the stem abuts against the cancellous bone.