The state of knee meniscal fibrocartilage in Liverpool necropsies.

The state of the fibrocartilaginous menisci of the adult knee joint has been studied at necropsies in the city of Liverpool on a random series of 94 white Europeans (55 men, 39 women) aged 21 to 94 yr. The left lateral meniscus was selected for particular attention; in 20 of the subjects the left medial meniscus was also examined. The gross and histological appearance of the superior and inferior surfaces of the lateral meniscus and of its free inner edge is described and illustrated at various ages. The findings from necropsy specimens indicate that the fibrocartilage of the adult meniscus is susceptible to a focal process of matrix fraying and splitting which has several features similar to those seen in fibrillation of hyaline articular cartilage. Certain differences in detail between meniscal and hyaline cartilage in the pattern of cell changes at sites of overt splitting are, however, apparent. The implications of the findings are discussed in terms of an hypothesis that cartilage fibrillation represents a disruption of the collagen framework, and that "wear", of the matrix due to mechanical factors plays a major part in its development.