Structural consequences of traumatising articular cartilage

SUMMARY Articular cartilage-on-bone has been subjected to repeated impact loading in vitro and the associated structural changes occurring in the general matrix examined by optical and transmission electron microscopy (TEM). The study shows that repeated trauma transforms the pseudorandom arrangement of fibrils comprising the general matrix of normal articular cartilage into a structural configuration strongly aligned in the radial direction and displaying a prominent waveform or crimp. This stress-induced structural transformation can be predicted from the application of a recently developed structural model of articular cartilage. Further, this altered structure bears a close resemblance to that commonly observed in articular cartilage exhibiting both non-progressive degeneration and osteoarthritic changes. Key phrases: repeated impact loading in vitro, stress-induced transformation of collagen architecture. Although a number of investigators have examined the response of articular cartilage to impact loading or trauma, most of these studies have provided only a superficial description of the structural change