Traumatic cartilage defects of the knee joint occur in an isolated way due to contusions or due to shear forces as a combined injury with ligamentous damage. They must be documented according to localisation, surface involved and depth. In the adult, only the fragment extending into subchondral bone can be refixed. Purely cartilagineous lesions heal spontaneously under partial repair with fibrocartilage; this can equally be surgically stimulated through surgical drillholes or impaction fractures with awls and pins. Since fibrocartilage is known to be mechanically insufficient and is often not resulting in sufficient sports- and working capacity newer methods and are getting more and more popular enabling the induction and production of hyaline or hyaline-like cartilage. Osteochondral transplantation from the own knee as plugs forming a mosaic has the advantage of being readily available for limited surface size. Repair to a hyaline-like cartilage using a chondrocyte suspension is also possible, and is used for bigger surfaces or defects, it needs however two operations. In the long term it will become the method of choice for defects over 4 cm2.