A prosthesis for placement into a joint space between two or more bones is disclosed. The prosthesis includes a body formed from a pre-formed solid one piece elastomer, wherein the elastomer is formed from a synthetic organic polymer that is biocompatible and has a modulus of elasticity and a mechanical strength between 0.5 MPa and 75 MPa. The body having a shape contoured to fit within a joint space between the femoral condyle, tubercle, and tibial plateau without any means of attachment.