[Treatment of cartilaginous defects in the knee: recommendations from the Dutch Orthopaedic Association].

Cartilaginous defects in the knee occur frequently and can cause the patient considerable limitations. They are diagnosed and classified by means of MRI and arthroscopy. The surgical options available to treat deep chondral lesions include bone marrow stimulation techniques (microfracture treatment), chondrocyte therapies (autologous chondrocyte implantation) and tissue replacement therapies (osteochondral autologous transplantation). Microfracture treatment and osteochondral autologous transplantation are suitable for treating chondral lesions that extend to the subchondral bone and are smaller than 2 and 4 cm2, respectively. Autologous chondrocyte implantation is a suitable method for treating single symptomatic chondral lesions larger than 2 cm2 in adults up to 50 years of age. There are no significant differences regarding the effectiveness of microfracture treatment, autologous chondrocyte implantation and osteochondral autologous transplantation for small defects: all show good clinical and functional short- and medium-term results. New second- and third-generation autologous chondrocyte implantation techniques seem to yield more sustainable tissue repair and better clinical long-term results for lesions larger than 4 cm2 in comparison to microfracture treatment.