Pathophysiology of Cartilage Injuries
Articular cartilage lesions represent one of the major unsolved problems in orthopedic surgery due to the limited capacity of articular cartilage for self-repair following trauma. The biological response of cartilage to injury varies depending on the extent of the traumatic event. When a lesion is confined to the superficial layer, the repair process is not initiated, as the inflammatory stimulus is too weak to stimulate the resident chondrocytes surrounding the lesion; consequently, the defect persists. However, when a full-thickness lesion occurs, reaching the vessels of the subchondral bone, the inflammatory stimulus is more important. Bleeding from the bone marrow occurs, allowing the access of growth factors and reparative cells to the lesion site. These cells are mainly fibroblasts in addition to a low percentage of mesenchymal stem cells. As a result, the newly formed reparative tissue differs from the normal hyaline cartilage in term of morphology, biochemical composition, and biomechanical properties. For these reasons it is called fibrocartilage. The aim of this chapter is to review the morphology, composition, and biomechanical function of normal cartilage and to present an analysis of the response of the cartilage tissue to the different traumas.
KeywordsArticular Cartilage Subchondral Bone Cartilage Lesion Deep Zone Collagen Network
- 4.Langworthy MJ, Nelson FRT, Coutts RD (2004) Basic science. In: Cole BJ and Malek MM (ed) Articular Cartilage Lesions: A Practical Guide to Assessment and Treatment. Springer, New York, pp 3–12Google Scholar
- 6.Mankin HJ, Mow VC (2000) Articular cartilage structure, composition, and function. In: Buckwalter JA, Einhorn TA (ed) Orthopaedic Basic Science. Biology and Biomechanics of the Musculoskeletal System. 2nd ed. Rosemont, Illinois: American Academy of Orthopaedic Surgeons, pp 458–470Google Scholar
- 7.Greco F, Lorini G, Specchia N (1990) L’influenza del sovraccarico sulla cartilagine articolare del ginocchio. Giornale italiano di Ortopedia e Traumatologia Vol XVI N. 1Google Scholar
- 8.Repu RU, Finlay JB (1977) Survival of articular cartilage after controller impact. J Bone Joint Surg 59A:1068–1076Google Scholar