In summary, most reports describe good results of mesenchymal implantation in treating cartilage defects, including symptomatic and functional improvement  as well filling of defects. On the other hand, histological  analysis indicates that true hyaline cartilage is rarely found in the regenerated tissue. Individual groups use different methods of implantation in terms of cell number and carrier materials. Furthermore, lack of controls makes it difficult to determine whether stem cell implantation is a significant, game-changing concept compared with other methods. A randomised, prospective clinical trial, preferably involving>100 patients and multiple centres, is necessary.