The book presents research in treating focal joint cartilage defects. Lipoaspirate fluid (LAF) cells have important applications in such areas as orthopedics, general surgery, plastic and repair or vascular surgery. Also discussed are cartilage tissue regeneration therapies using collagen scaffolds and multipotent mesenchymal cells; this offers the possibility of making real "biological arthroplasties". The regeneration of cartilage tissue by injecting stem cell concentrates gives hope to patients suffering from cartilage degradation. Keywords: Biomaterials, Osteochondral Repair, Lipoaspirate Fluid (LAF) Cells, Arthrosis, Focal Joint Cartilage Defects, Physiopathology of Cartilage Lesions, Diagnosis of Cartilage Lesions, Treatment of Cartilage Lesions, Plastic Surgery, Vascular Surgery, Repair Surgery, Orthopedics, Biological Arthroplasties