Effect of mechanical load on articular cartilage collagen structure: A scanning electron-microscopic study

Little is known about the morphological effect of a mechanical load upon ar ticular cartilage. The objective of this study was to describe and quantify the deformation of the articular cartilage collagen structure of the tibia l plateau under static loading. Whole intact rabbit knee joints were loaded in vitro by simulating a quadriceps force of 3 x, 1 x or 0.5 x body weight thigh, medium, low) over durations of 30 or 5 min (long, short). Specimens were cryopreserved while under load and prepared for morphological evaluat ion by field emission scanning electron microscopy. Under high force and lo ng duration loading the collagen fibers exhibited high deformation with an increased thickness of the layer of collagen fibers oriented almost paralle l to the surface and a cartilage thickness reduced to 54%. Collagen fiber d eformation occurred mostly in the transitional and upper radial zone. The a rea of tibial indentation and the cartilage thickness reduction increased w ith magnitude and duration of load. The collagen matrix did show a bulging edge at the border of the meniscus and exhibited remarkable deformation und er the meniscus. Copyright (C) 2000 S. Karger AG, Basel.