US Patent 7766969 Modular progressive implant for a joint articulation surface

An implant for on a resected articulation surface of a bone includes a tray having a top surface and opposition surface. An opening extends completely through the tray between the top surface and the bone apposition surface. A bearing member is mounted on the top surface of the tray, the bearing member having a top articular surface. Anchor downwardly projects away from the bone apposition surface of the tray, the anchor being adapted to engage the bone and being configured so that the anchor can selective pass completely through the opening of the tray. A fastener connects the anchor to the tray.