What is osteoarthritis?

Osteoarthrosis is a chronic progressive noninflammatory disease of synovial joints of various etiologies, characterized by articular cartilage degeneration, structural changes in the subchondral bone, and an explicit or hidden synovitis.

Until the mid-1980s, there was no unified definition of osteoarthritis. Usually it was treated as a disease of unknown etiology, in which the cartilage is primarily affected (in contrast to rheumatoid arthritis, in which the synovial membrane is primarily affected), indicated the degenerative nature of the pathological process.

In 1986, the Osteoarthrosis Subcommittee of the Committee on Diagnostic and Therapeutic Criteria of the American College of Rheumatology (ACR) proposed the following definition of osteoarthritis: "Osteoarthritis is a heterogeneous group of diseases that lead to the appearance of joint symptoms due to a violation of the integrity of the articular cartilage, and changes in the underlying bone " ).

The most significant and fully responding to modern theories of the etiology and pathogenesis of osteoarthrosis, and also most fully reflecting the essence of this disease, is the definition of ACR (1995): "Osteoarthritis is a disease caused by the action of biological and mechanical factors destabilizing the normal relationship between degradation and chondrocyte synthesis, extracellular matrix of articular cartilage and subchondral bone ".

A broader but more complex definition, summarizing the clinical, pathophysiological, biochemical and biomechanical changes characteristic of osteoarthritis, was developed at a conference on the etiopathogenesis of osteoarthritis, organized by the National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases, National Institute of Aging, American Academy of Orthopedic Surgeons, National Arthritis Advisory Board and Arthritis Foundation (Brandt KD et al., 1986): "Clinically, osteoarthritis is characterized by joint pain, painful palpation, limited mobility, crepitus, intermittent effusion and okalnym inflammation of varying severity, but without systemic manifestations. Pathological changes in osteoarthritis are characterized by uneven loss of cartilage, more often in areas of increased stress, sclerosis of the subchondral bone, the formation of subchondral cysts, marginal osteophytes, increased metaphyseal blood flow and inflammation of the synovial membrane. Histologically, at an early stage, osteoarthrosis is characterized by fragmentation of the surface of the articular cartilage, proliferation of chondrocytes, the formation of vertical cracks in the cartilage, the deposition of various crystals, remodeling and, possibly, germination of the transient "wavy" line with blood vessels. Osteoarthritis is also characterized by the presence of signs of a reparative response (in particular, osteophytes); later there is a total loss of cartilage, osteosclerosis and focal osteonecrosis of the subchondral bone. Biomechanically, osteoarthritis is characterized by a change in the ability of articular cartilage to resist stretching, compression, changing its water permeability, increasing its water concentration and excessive swelling. Biochemically, osteoarthritis is characterized by a decrease in the concentration of proteoglycans, possibly by changing their sizes and aggregation, by changing the size and breaking of collagen fibers, by increasing the synthesis and degradation of matrix macromolecules. "

In the definition of osteoarthritis proposed at the seminar "New horizons in osteoarthritis" (USA, 1994), conducted by the American Academy of Orthopedic Surgeons, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institute of Aging, Arthritis Foundation and Orthopedic Research and Education Foundation, stresses that osteoarthritis includes several nosologies: "Osteoarthrosis is a group of cross-linked diseases that have different etiologies, but the same biological, morphological and clinical outcomes. The pathological process affects not only the articular cartilage, but also extends to the entire joint, including the subchondral bone, ligaments, capsule, synovial membrane, and periarticular muscles. Ultimately, there is degeneration of the articular cartilage with its disintegration, the formation of cracks, ulceration and its complete loss. "

At the seminar held in 1995, the following definition was proposed: "Osteoarthritis is the result of the action of biological and mechanical factors that disturb the balance between the processes of degradation and synthesis of the extracellular matrix of articular cartilage and subchondral bone. Osteoarthritis can be initiated by a variety of factors, such as genetic, evolutionary, metabolic and traumatic, all the tissues of the synovial joint are involved in the pathological process in osteoarthritis. Ultimately, osteoarthritis is manifested by morphological, biochemical, molecular and biomechanical changes in cells and matrix that lead to thinning, defibration, ulceration, loss of articular cartilage, osteosclerosis with sharp thickening and densification of the cortical layer of the subchondral bone, osteophytosis, and formation of sub chondral cysts. The clinical picture of osteoarthritis is characterized by arthralgia, tenderness and limitation of movements, crepitus, a periodic accumulation of effusion in the joint cavity, an inflammatory process of varying severity without systemic manifestations. "

Historical reference on osteoarthritis

According to researchers, people have always had osteoarthritis. Degenerative changes in bones were found in fossil remains of Pithecanthropus erectus (Javanese man). Similar changes were found in the bones of the inhabitants of the Nubian cave, which lived 10,000 years before Christ (Brugsch HG, 1957), as well as in the skeletons of ancient Anglo-Saxons.

Hippocrates described the disease as "arthritis, affecting large joints, which does not go beyond the affected joint." Later, these clinical observations were forgotten until the end of the XVIII century, when clinicians again tried to divide arthropathies into groups. Despite the fact that the first detailed and clinically complete description of osteoarthritis was made in 1805 by John Haygarth (a year before William Geberden described knots in the area of distal interphalangeal joints), successful attempts to isolate OA into a disease other than rheumatoid arthritis were done only in the beginning of XX century. (Garrod AE, 1907; Hoffa A., Wollenberg GA, 1908; Nichols EH, Richardson FL, 1909). Studying "non-tubercular" arthritis, E.N. NicholsH FL Richardson (1909) identified two types of joint changes: "proliferative type with a tendency to destruction of the articular cartilage, leading to ankylosis" and "degenerative type with a tendency to destruction of the articular cartilage without ankylosing." The latter option is obviously a description of osteoarthritis. Only after the publication of RL Cecil and VN. Archer in 1926, the concept of osteoarthritis as a separate disease was accepted by the broad medical community.