Osteoarthritis occurs when the cartilage cushions between the joints break down, causing pain and stiffness. Cartilage is a firm, rubbery tissue that cushions bones and surrounds the joints, allowing bones to glide over one another. There are several factors thought to cause the breakdown of the cartilage surrounding joints. Cartilage can break down with age, but it can also tear away as the result of an injury. Other factors that could cause osteoarthritis include a genetic predisposition, a weight problem (being overweight increases the risk of cartilage wearing down in the hip, knee, and ankle joints), fractures, or long-term overuse from athletic activities.
Without the cartilage, when the bones rub together it can cause swelling, stiffness, and pain. There is also the possibility of a ripple effect when one joint loses cartilage. Other, related joints can over-compensate or can’t function normally, causing ligaments to become weak. An estimated 12 percent of Americans suffer from osteoarthritis between their early teen years and their mid-70s.