Osteoarthritis (OA) is the most common joint disorder. It is caused by "wear and tear" on a joint.
Cartilage, the firm, rubbery tissue that cushions the joints and allows bones to glide over one another, can break down and wear away over time. As a result, the bones rub together, causing pain, swelling and stiffness.
Bony spurs or extra bone may form around the joint, allowing the ligaments and muscles around the joint to become weaker and stiffer.
The exact cause of osteoarthritis is often unknown, but aging, being overweight, and having a joint injury are the strongest risk factors. The first symptoms of osteoarthritis usually appear in middle age or by age 70. Many people that show signs of the disease on x-rays will also experience symptoms. Before age 55, osteoarthritis occurs equally in men and women. After age 55, it is more common in women.
Other factors that lead to osteoarthritis:
- Osteoarthritis tends to run in families.
- Being overweight increases the risk of osteoarthritis in the knee.
- Fractures or other joint injuries can lead to osteoarthritis later in life.
- Long-term overuse at work or in sports increases the risk of osteoarthritis.
Medical conditions that can lead to osteoarthritis include:
- Bleeding disorders that cause bleeding in the joint, such as hemophilia.
- Disorders that block the blood supply near a joint can lead to avascular necrosis.
- Other types of arthritis, such as chronic gout, pseudogout, rheumatoid arthritis or psoriatic arthritis.
Patients with osteoarthritis may experience the following symptoms:
- Pain and stiffness in the joints are the most common symptoms of osteoarthritis. The pain is often worse after use of the joint and when placing weight or pressure on the joint.
- Fluid can build up in the joint (an effusion), and can also cause pain.
- Over time, the joints become more painful, and patients may notice a rubbing, grating or crackling sound when moving the joint.
- The phrase "morning stiffness" refers to the pain and stiffness people feel when they first wake up in the morning. In osteoarthritis, this stiffness usually lasts 30 minutes or less and is improved by mild activity that "warms up" the joint.
- During the day, the pain may get worse with activity and feel better when resting. Eventually, the pain may be present when resting and may even wake people up at night.
- Other people might have no symptoms even though X-rays show the changes of osteoarthritis.
A physical exam can show:
- Joint movement causes a cracking (grating) sound, called crepitation
- Joint swelling (due to fluid build-up or enlargement of bones around the joints)
- Limited range of motion
- Tenderness when the joint is pressed
- Normal movement may be painful
- X-rays of the affected joints may show a loss of the joint space, bone spurs and a wearing down of the ends of the bone
Blood tests are not used in diagnosing osteoarthritis, but can be helpful to rule out other forms of arthritis.
Osteoarthritis cannot be cured and it will often become worse over time. However, osteoarthritis symptoms can be controlled with physical and/or occupational therapy, over-the-counter pain relievers, steroid injections and lifestyle changes.
Although these treatments cannot make the arthritis go away, they can often delay or postpone surgery. Advanced cases of osteoarthritis may require surgery to replace or repair the damaged joints.
- Osteoarthritis Research at Penn Rheumatology
Dr. Carla Scanzello, a recent addition to the faculty at Penn, is a rheumatologist who has dedicated her career to understanding the causes and consequences of joint inflammation in osteoarthritis, and the risk factors for development of osteoarthritis in patients with joint injuries. She hopes that her research will lead to better care for patients in three specific ways. First, she is working to develop novel ways of identifying patients with the earliest signs of inflammation and osteoarthritis, before signs of the disease show up on x-rays. By identifying patients before arthritic joint damage is extensive, both current and future treatments should be more effective. Second, she aims to develop clinical tests that can help us determine which patients are more at risk for developing osteoarthritis after a joint injury. By understanding an individual patient's risk, treatments aimed at preventing future arthritis can be specifically developed and prescribed. Finally, understanding the molecular details of how inflammation impacts osteoarthritis development and progression should lead to novel treatments aimed at blocking harmful responses and promoting healing responses in the joint.
Dr. Scanzello sees patients and operates a research laboratory at the Philadelphia VA Medical Center