Knorpelschaden und Gonarthrose

Abstract

. Abstract Articular cartilage homoeostasis is critical for joint function. The steady state homoeostasis of articular cartilage matrix composits (above all collagen type II and proteoglycans) is a balance be-tween anabolic morphogens such as cartilage derived morpho-genetic proteins. Cartilage composites of superficial tangential zone, middle zone, deep radial zone, tide mark and subchondral bone. The superior zone is rich on radial orientated collagen fibers. This causes a high mechanical resistance against pressure and shear forces. The deep layers contain more proteoglycans and water. This creates a preload for the collagen fibers as well as neutralizes pressure forces too. The matrix turnover is regulated by cytokines which activate matrix metalloproteinases. The biomechanical property of cartilage is characterized by vis-coelasticity. Cartilage degeneration is caused by the increase of katabolic processes. There is a decrease of matrix composites like collagen type II and proteoglycans. The increases of water content products the edema and the chondrocytes become apoptop-tically. This is conformed by a decreased mechanical resistance. The cartilage defects results from this loss of mechanical properties. Secondary are damages within the subchondral bone and the synovia. This is characteristically for the osteoarthritis.