Osteoarthritis, also called degenerative arthritis, is a gradual breakdown of cartilage in the joints. Cartilage is a tough, flexible connective tissue that protects the ends of bones in the joints. Osteoarthritis is common in the knees because the knees bear the weight of the body. Osteoarthritis of the knee can severely impact a person's lifestyle.
Causes and Risk Factors
Osteoarthritis commonly develops as a result of the wear and tear of aging. It also frequently results from traumatic injury to the joint. Osteoarthritis of the knee is more common in older people, in women, and in people who have occupations that place increased stress on the knees. People who have certain diseases, bone deformities or a genetic predisposition are also at a higher risk. Obesity can also raise a person's risk for osteoarthritis of the knee, because extra body weight increases stress on the knee joints.
In a healthy knee, the ends of the bones are covered by a layer of cartilage. Healthy cartilage allows the bones to glide smoothly against each other. But in a knee with osteoarthritis, this cartilage begins to deteriorate and wear away. Repetitive motion or injury may speed this deterioration. Eventually, the bones may rub directly against each other.
Bone Spur Formation
This rubbing can cause the gradual growth of bony bumps along the edge of the joint. These lumps, called bone spurs (or osteophytes), can cause joint pain.