Articular surface defects will not heal spontaneously. Localized defects, e.g., in the knee joint, should be treated with transplantation of autologous cells containing material of different composition. For transplantation of osteochondral pegs they are grafted from minor loaded joint areas and implanted into highly loaded defect regions. For autologous cartilage cell transplantation they are proliferated in vitro and then implanted into the defect zone under an periostal flap, harvested from the proximal tibia and sutured into the cartilage level around the defect. Autologous paste of cartilage and cancellous bone is transplanted into aggressively prepared defects with the concept of regrowing articular cartilage out of the transplanted cells and the subchondral bone.