Osteoarthritis can be classified as primary or secondary. Primary osteoarthritis has an unknown cause, while secondary osteoarthritis is caused by another disease, infection, injury, or deformity. Osteoarthritis is characterized by the breakdown of cartilage in the joint and adjacent bone. As the cartilage wears down, the bone ends may thicken, forming bony growths or spurs that interfere with joint movement. In addition, bits of bone and cartilage may float in the joint space and fluid-filled cysts may form in the bone, limiting joint movement.
Excessive weight can put undue stress on such joints as the knees over time.
Injury may also result from repeated overuse or misuse over a period of time. The most common symptom of osteoarthritis is pain after overuse of a joint or prolonged inactivity of a joint. The most common joints affected by osteoarthritis include the hips, knees, fingers, feet, and spine. Symptoms of osteoarthritis usually develop slowly over many years. The following are the most common symptoms of osteoarthritis.