A prosthesis is provided for implantation into a body joint, such as a knee joint compartment between a femoral condyle and its corresponding tibial plateau, without requiring bone resection. The prosthesis includes a body having a generally elliptical shape in plan and including opposed top and bottom surfaces. The body includes a supporting portion and a coating portion, where the supporting portion has at least one surface at least partially disposed within an interior of the body and the coating portion has at least one surface disposed on an exterior of the body. The supporting portion is constructed from a higher modulus material than the coating portion such that the body is at least slightly deformable.