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[Indications and implementation of recommendations of the working group "Tissue Regeneration and Tissue Substitutes" for autologous chondrocyte transplantation (ACT)].

For the treatment of full-thickness articular cartilage lesions of the knee joint, as a result of trauma or osteochondritis dissecans, a variety of biological reconstruction techniques have been developed. Different studies, some of which were performed as randomised, prospective clinical studies, showed that the autologous chondrocyte transplantation (ACT) provides the most satisfying and reliable method of cartilage reconstruction in the adult when applied to defects exceeding 4 cm (2). Based on these results, ACT seems to be of economic benefit, as the risk of developing osteoarthritis correlates significantly with the size of the cartilage defect, when not treated properly and in time. Surveying the studies on basic scientific aspects of ACT, cartilage defect animal models and clinical studies, it can be concluded that clinical results of ACT depend on a variety of factors. In this review, published by the joined advisory board of the German Societies of Traumatology (DGU) and Orthopaedic Surgery (DGOOC), we summarize the current knowledge available and the state of the art concerning ACT. Especially we discuss the advantages of different procedures, methods for treating knee cartilage defects and factors that influence the outcome of the different treatment regimens, with the aim to develop guidelines for the correct indication and application of the ACT.