Arthritis is characterised by progressive deterioration of joint cartilage. If these degenerative changes occur in the knee joint, the condition is referred to as arthritis of the knee (gonarthritis). The ends of the bones forming the knee joint are covered with cartilage, which serves to make these contact surfaces as smooth and frictionless as possible. Over the years, progressive deterioration of these cartilage surfaces occurs. The causes of arthritis are diverse and, in many cases, multiple. First and foremost is, of course, excessive wear and tear on the joints. Although progressive wearing is "normal" and occurs in everyone, some families have a genetic predisposition to arthritis. Secondly, knee deformities such as bowlegs (genu varum) and knock-knees (genu valgum) result in uneven weight distribution across the knee. As a result, some compartments of the knee are overloaded and overused. Early joint surface damage (arthritis) develops at these sites. Obesity and physical inactivity also promote the development of arthritis. Any trauma resulting in torn ligaments or bony lesions in the knee over the course of time contribute to the development of arthritis.
Once the cartilage damage has occurred, it does not go away because the cartilage is unable to repair itself.
Depending on the severity of the disease, arthritis produces a number of different symptoms, but the primary symptom is pain. In the early stages of the disease, pain occurs when performing certain movements, such as climbing stairs and walking uphill, and later occurs during other activities. Knee swelling and fluid accumulation may also occur, especially after physical activity. Another common symptom is resting pain, which occurs in the affected joint when the patient is not performing any activity but simply lying in bed, etc. The range of motion of the joint decreases progressively, firstly, because the patient tends to avoid using the joint to avoid pain and, secondly, because of the degenerative changes occurring in the joint
