Treatment of cartilage defects

Cartilage defects cause a significant loss of knee function and represent a first stage of the arthrosis, which is very difficult to treat. The available treatment alternatives are limited due to a minimal capability of the hyaline cartilage to regenerate. The widespread conservative treatment of cartilage defects is generally limited to the application of symptom-reducing methods, since conclusive proof of a structure-modifying effect is still lacking for the available medication. Certain relevance was reached for the relatively cheap oral supplementation with GAG's, a method which proved to show a certain long-term success in clinical studies. The procedures such as drilling, abrasion arthroplasty or microfracture of the subchondral plate stimulate bone marrow cells to repair the defect with scar tissue but miss a permanent improvement of the symptoms. Also autologous chondrocyte implantation in combination with periosteum transplantation results in the creation of a hyaline-like tissue and the long-term effect of this treatment remains questionable. Autologous osteochondral transplantation enables the transfer of a vital and functioning hyaline cartilage. However, the lacking side-to-side integration of the transplanted cartilage disturbs the integrity of the cartilage surface. In addition, the defect caused by harvesting the donor plugs represents a prognostic uncertainty. Despite the disadvantages of the treatment the methods cited show good subjective and objective improvement of the symptoms in the range of years. In the future, new engineering methods will enable production of the hyaline cartilage in bioreactors under appropriate biological and physico-mechanical conditions in three-dimensional cell cultures on scaffolds and matrices.