An implant system comprises an implant plate adapted to be positioned on a surface of a resected bone. The implant plate has a plurality of openings. A plurality of independently positionable pegs attach the implant plate to the bone. Each peg has a longitudinal axis and comprises: a peg body and a retaining device. The peg body is inserted into a peg hole in the bone. The peg body has a transverse dimension in a direction normal to the longitudinal axis, the transverse dimension larger than the openings of the plate. The retaining device is separate from the peg body, and is configured to attach to the peg body, with at least a first portion of the retaining device positioned above an upper surface of the implant plate, and a connecting portion of the retaining device extending through one of the openings of the implant plate.