Osteochondral defects: present situation and tissue engineering approaches.

Articular cartilage is often damaged due to trauma or degenerative diseases, resulting in severe pain and disability. Most clinical approaches have been shown to have limited capacity to treat cartilage lesions. Tissue engineering (TE) has been proposed as an alternative strategy to repair cartilage. Cartilage defects often penetrate to the subchondral bone, or full-thickness defects are also produced in some therapeutic procedures. Therefore, in TE strategies one should also consider the need for a simultaneous regeneration of both cartilage and subchondral bone in situations where osteochondral defects are present, or to provide an enhanced support for the cartilage hybrid construct. In this review, different concepts related to TE in osteochondral regeneration will be discussed. The focus is on the need to produce new biphasic scaffolds that will provide differentiated and adequate conditions for guiding the growth of the two tissues, satisfying their different biological and functional requirements.