Osteoarthritis (OA) is the wearing down of structures in the joint that leads to pain and stiffness. It can affect any joint but is most common in knees, hip, spine, and hands.
The cartilage is often the first structure of the knee that becomes damaged. Cartilage is a smooth tissue that covers bone surfaces inside the joint that allows the bones to move smoothly over each other. The breakdown of this cartilage causes rough uneven surfaces of the joint which cause pain and discomfort with movement. Eventually the cartilage may completely wear away leaving the bone surfaces bare making movement very difficult and painful. Over time this damage can lead to extra stress and eventual damage to other structures of the joint such as ligaments, tendons, and synovium, a capsule that surrounds the joint.
OA is a degenerative joint disease, which means it gradually worsens over time, as a result OA is more common in adults over 50 years of age. OA can also affect people differently. Some may have mild symptoms with little progression, while others may have symptoms that significantly worsen over time, affecting mobility and quality of life.
OA is often the result of wear and tear on joints over time. People may be more or less likely to have OA because of a combination of genetics and environment. Factors that can increase stress on joints and increase the amount of wear and tear include:
- Misalignment of bones
- Previous trauma to the joint
- Excess weight
- Muscle and nerve problems that affect how the joint moves
- Health conditions that affect joints and surrounding tissues
- Repetitive movements over long periods of time
In some cases, the cause of OA may be unknown.
- Reviewer: Michael Woods, MD
- Review Date: 05/2015 -
- Update Date: 05/20/2015 -