A prosthetic articular surface for implantation in a joint such as the knee is provided. The prosthetic articular surface comprises a contoured plate having two sides, one side of which is a bone-contacting side and the other side of which is an articular side, and at least one post extending from the bone contacting side. A method of placing the prosthesis at an implant site, a guide tool for facilitating implantation, and a surgical kit containing the prosthesis also are provided. The prosthetic articular surface, method of implanting the prosthesis, guide tool for facilitating implantation, and surgical kit containing the prosthesis may be used to replace or augment a damaged joint in the knee.