Subchondral Bone and Reason for Surgery.

The subchondral bone plays a key role in the integrity and repair of the entire osteochondral unit. Its unique anatomical structure is well suited to support the articular cartilage, even providing nutrition for its basal layers. The subchondral bone becomes a problem in reconstructive cartilage surgery when violated, for example, following osteochondral fractures or in osteochondritis dissecans (OCD), thus leading to an osteochondral lesion. Such osteochondral defects are difficult to treat because the subchondral bone and the articular cartilage have very dissimilar intrinsic healing capacities (Huey et al., 2012; Hunziker, 1999; Hunziker, 2009). Recent clinical evidence also pointed to the role of subchondral bone alterations in the course of spontaneous and surgical cartilage repair. In the treatment of cartilage defects, it is imperative to establish the etiology of the subchondral bone lesion and then address the specific pathology accordingly. This chapter will focus on the subchondral bone and its relevance for reconstructive cartilage surgery. It is based on individual presentations from the Instructional Course Lecture “Subchondral bone and reason for surgery” (Table 1).