[New aspects of the functional anatomy of the menisci]

The present study concerned 16 human menisci: light, transmission (TEM) and scanning electron microscopic (SEM) techniques were used in addition to histochemical examinations, to define the microstructure of their collagenous fibre systems. A characteristic arrangement of the fibrils was noted. The diameters of the collagen fibrils ranged between 20 and 190 nm in the medial meniscus, the mean value being 67.5 nm (lateral: 70 nm). Many collagen type VI fibrils were detected, and collagen type IV was present. Such an organization has implications for knee joint stability, the variability of the fibril diameters and the characteristic arrangement giving the tissue great tensile stiffness and allows adaptation to all physiological loading conditions. On the surface of the menisci openings of canal-like structures were noted. Their characteristic distribution indicates that they carry nutrients from the synovial fluid to the normal avascular areas of the menisci.