Arthritis is the most common cause of disability in the United States, limiting the activities of nearly 52 million adults.1 Arthritis is a disease that afflicts the joints and results in inflammation, usually causing pain and restricted mobility. In arthritis, the space between the joint narrows. This leads to wear and tear on the joint and causes the two bones in your knee to come in direct contact and cause pain.
Arthritis can be caused by:
- Age-related wear and tear
- Injury to the knee
- Excess body weight
- Bone deformities
Most arthritis induced knee pain is caused by one of three types: osteoarthritis, rheumatoid arthritis, and traumatic arthritis.
The most common form of arthritis today is osteoarthritis and affects an estimated 27 million US adults.3 Disease onset is gradual, usually occurring between the ages of 40 and 50, and often in individuals with a family history of arthritis.2 Osteoarthritis is usually a slowly progressive degenerative disease in which the joint cartilage gradually wears away. When this happens, bone rubs against bone which causes pain and stiffness in the joint.
Rheumatoid arthritis is an inflammatory type of arthritis that can destroy the joint cartilage. It can occur at any age and generally affects both knees. Rheumatoid arthritis results when the synovial membrane becomes thickened and inflamed, causing an abundance of fluid and over-fills the joint space. Chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain and stiffness.
Similar to osteoarthritis, traumatic arthritis is a slow progressive degenerative disease and may develop years after a fracture, ligament injury or meniscus tear. Serious knee injuries may damage articular cartilage over time causing knee pain and limiting function.
Typical symptoms of arthritis include:
- Gradual development of pain
- Joint stiffness
- Swelling of joint
- Pain and swelling that is worse in the morning or after a period of inactivity and may also increase after activities such as walking, stair climbing or kneeling