The most common cause of chronic pain in weight-bearing joints, such as the hip and knee joints, is arthritis. Osteoarthritis, rheumatoid arthritis and traumatic arthritis are the most common forms of this disease. Osteoarthritis usually occurs after age 50 and often in people with a family history of arthritis. 2 Osteoarthritis is a disease of articular cartilage, a soft, gel-like tissue that acts as a shock absorber for joints and protects bones from rubbing against each other. Rheumatoid arthritis is a disease in which the synovial membrane that lines joints becomes inflamed, produces too much synovial fluid and damages the articular cartilage, causing pain and stiffness.
Traumatic arthritis can follow a serious hip or knee injury.
The articular cartilage becomes damaged, which results in hip pain and stiffness. A knee fracture or serious tear of the knee s ligaments also may damage articular cartilage that produces knee pain and limits knee function. Osteoarthritis is the most prevalent form of arthritis among Americans older than 65 and is the leading cause of chronic disability. About 21 million people in the United States have osteroarthritis. As osteoarthritis progresses, changes can be easily seen on X-ray.