ABSTRACT
A need exists for a method that biologically regenerates full thickness defects in articular cartilage defects. Without adequate in vitro alternatives so far, animal models of cartilage defect are still playing a very important role at this frontier. The animals used for heterotopic models include nude mice, syngenic mice, rats, and rabbits. There are mainly two types of defects, focal full thickness defect and partial-thickness defect. The commonly used animals are rabbits and dogs which are the first choices for the studies on cartilage repair. Cartilage components such as hyaline cartilage or fibrocartilage have been generated in the defects of experimental animals and human patients. Various synthetic materials have been investigated as replacement materials for a cartilage defect. Elastomeric materials such as silicone rubber have replaced articular cartilage in prosthetic finger joints, but have limited fatigue resistance which limits their use in weight-bearing conditions. Growth factors play a very important role in the process of chondrogenesis.
