In order to improve an implant for the replacement of at least a part of a
natural articular surface of a bone forming part of a joint comprising an
anchorage surface abutting against the remaining bone and an artificial
articular surface directed away from the bone in such a way that as
little bone substance as possible should be removed in a simple manner
for insertion of the implant, it is proposed that the anchorage surface
comprises at least one cylindrically shaped area, which defines a
cylinder axis.