The fibrillar system constitutes the supporting framework of cartilage, the early weakening of which indicates loss of cartilaginous elasticity. Loss of elasticity is followed by erosion, marginal proliferations and, in the later stages, by invasion and replacement of cartilage by connective tissue. The degenerative process begins with the alteration of the fibrillar system of support. Degeneration increases with further alterations in the fibrillar system, and ends with the destruction of the joint surface.
A study of the reaction of the fibrillar system, therefore, becomes essential to an understanding of the changes characteristic of arthritis deformans. Further study of fibrillar systems would seem valuable in other pathological conditions. Such studies may be readily carried out by the use of polarized light; the technique is simple and interpretation of changes, otherwise difficult or impossible to recognize, is made possible.