Osteoarthritis (OA) is a joint disease, and the process affects the entire joint / bone, cartilage surrounding the joint structures (ligaments and muscles). It usually develops as a result of functional impairment of the locomotor system, and is the result of mechanical and biological changes that disrupt normal relations in the joint. Driven by the various risk factors such as genetic predisposition, developmental disorders, endocrine disorders, obesity, and repeated trauma of the joint. It can affect any joint in the body but most commonly occurs through the loaded joints (knee and hip), and the small joints of hand. Main clinical sign is pain that is initially present in the movement and when the joint is loaded, and how the process is progressing pain occurs at rest. Other symptoms include stiffness, limited mobility, and crepitus in the joint. As the disease progress occurs, atrophy of surrounding muscles and ligament mechanism leads to instability and decreased mobility of the joint. Pathological process starts at the surface and edges of the joint cartilage, which is changed, loses elasticity, and creates small and later deeper damage, and then the process expands and engages parts of the subchondral bone. There are primary arthrosis (which are of unknown origin) and secondary arthrosis (resulting from trauma, congenital anomalies, metabolic and genetic factors). The diagnosis of osteoarthritis should be based on history, clinical examination of patients and radiological diagnosis. The most common radiological changes in joints are: narrowing of the joint cavity, subchondral bone sclerosis, cystic changes in subchondral bone and osteophytes. Treatment of the disease is reduced to a combination of non-pharmacological (medical gymnastics and physical procedures) and pharmacological treatment (analgesics, glucocorticoids) and operative treatment for those patients where previous treatments have not proved successful. Osteoarthritis of the knee is more common in women middle aged and elderly. The leading symptom of knee osteoarthritis is pain that first occurs when walking (especially the stairs), in squats and kneeling and in getting up from a seated position. As the disease progresses the symptoms become more pronounced, and are present at rest. The knee joint occasionally comes up swelling of the joint.