This is a joint disease that can affect one or both knees, and is characterised by worn cartilage. Cartilage, along with the menisci, ligaments and muscles, facilitates movement of the joint. The disease causes the cartilage and menisci to lose their qualities and function. The three basic types of joint disorders that can affect the knee are:

Osteoarthritis or arthrosis, the most common form of arthritis of the knee. OA is usually a slow, progressive degenerative disease in which the cartilage of the joint is gradually worn away. It generally affects middle-aged and older people.

1. Artritis reumatoide (también conocida como RA, su sigla en inglés) es un tipo de artritis inflamatoria que puede destruir el cartílago de la articulación. RA puede ocurrir a cualquier edad. RA generalmente afecta ambas rodillas.
2. Rheumatoid arthritis (also known as RA) is a type of inflammatory arthritis that can damage joint cartilage. RA can occur at any age and usually affects both knees.
3. Traumatic arthritis can develop after an injury to the knee. This type of arthritis is similar to osteoarthritis and can develop years after a fracture, meniscus tear, or ligament damage.

Osteoarthritis Symptoms

Generally, pain associated with arthritis develops gradually, although sudden onset can also occur. The joint may become stiff and swollen, making it difficult to bend or extend the knee. The pain and swelling are worse in the morning or after a period of inactivity. Pain may also increase after activities such as walking, climbing stairs, or kneeling. Often the pain can cause a feeling of weakness in the knee, resulting in the patient becoming immobile or falling. Changes in the weather (cold or humidity) also affect the level of pain.