Several mechanical methods, such as microfracture, debridement and/or lavage, mosaicplasty, but also the more complex method of tissue engineering autologous chondroyte implantation are clinically applied for the treatment of chondral and osteochondral lesions of the knee. This report evaluates whether the implantation of a ready-made cell-free collagen-typ Imatrix (CaReS®-1S) leads to better results than these established methods.