Cell therapy for the treatment of cartilage defects

In the last decades, orthopedic surgery has advanced considerably with improvements in prosthetic designs, quality of materials, navigation systems, and biotechnology. The treatment of large cartilage defects in the knee remains a clinical challenge and is an example of how new technologies have fundamentally changed the way we treat these lesions today. Current methods include the perforation of the subchondral bone to recruit repairing cells locally (microfractures), autologous osteochondral grafting (mosaicplasty), and the implantation of competent cells within the defect. Three major strategies are currently being studied to repair cartilage lesions using cell therapy: (i) the implantation of culture expanded cells seeded onto biodegradable scaffolds; (ii) the implantation of a more or less pre-shaped and structured tissue, obtained in vitro by the assembly and three-dimensional culture of cells and a resorbable matrix; (iii) the stimulation of in situ tissue repair by different means, including growth factors or genetically modified cells. Surgeons treating cartilage defects will have an increasing variety of treatment options available, some of which will probably supersede current procedures in the near future. Although very promising, these techniques are invasive and expensive, and several issues should be overcome before they can be adapted for widespread clinical use.