[Pathology of primary inflammatory and primary degenerative changes in joints]

The author describes, from a general pathological viewpoint, the primary inflammatory arthropathies (arthritic diseases) and the primary degenerative arthropathies (arthroses), basing himself on a description of the joint as a complex open system consisting primarily of the highly vascularized synovial membrane, the synovial fluid and the hyaline articular cartilage. In the case of arthritis the primary lesion occurs in the synovial membrane. Different quantitative and qualitative morphological findings are obtained depending on the causes and duration of the disease and the pathomechanisms involved and, more specifically, on the involvement, or otherwise, of immunological mechanisms in the pathogenesis of arthritis. A classification of arthritic diseases following this concept is proposed. In the case of arthroses the primary lesion occurs in the non-vascularized hyaline cartilage. The latter reacts basically with metabolic disturbances which, from a morphological viewpoint, manifest themselves as degeneration and finally lead to cartilage necrosis. A distinction is made between primary arthrosis and secondary arthroses of known etiology. The close metabolic interaction of the synovial membrane and articular cartilage is the reason why, depending on the duration of the disease, arthritis develops into secondary arthrosis and the latter into secondary arthritis.