Figure 1.

Basic anatomy of the knee, with the meniscus located within the knee joint between the tibial plateau and the femoral condyles (A), which consists of distinct zones of varying cell populations that are distinct in morphology and phenotype; the inner region contains rounded or oval shaped fibrochondrocytes that produce type II collagen, whereas the outer region is mainly populated by fibroblast-like cells and randomly oriented type I collagen. Aggrecan, which is the major proteoglycan, is organized in a complex architecture and provides the tissue-specific biomechanical characteristics (B).