Osteoarthritis is the most common form of arthritis, affecting millions of people worldwide. It happens when the protective cartilage that cushions the ends of the bones wears down over time.
Although osteoarthritis can damage any joint, the condition most commonly affects joints in the hands, knees, hips and spine.
Osteoarthritis symptoms can usually be managed, although the damage to joints can't be reversed. Staying active, maintaining a healthy weight and receiving certain treatments might slow progression of the disease and help improve pain and joint function.
Osteoarthritis symptoms often develop slowly and worsen over time. Symptoms of osteoarthritis include:

In osteoarthritis of the spine, disks narrow and bone spurs form.

The hip joint on the right side of the image shows bone spurs and worn cartilage caused by osteoarthritis.
If joint pain or stiffness doesn't go away, make an appointment with your healthcare professional.
Osteoarthritis happens when the cartilage that cushions the ends of bones in the joints gradually wears away. Cartilage is a firm, slippery tissue that allows nearly frictionless joint motion.
Eventually, if the cartilage wears down completely, bone will rub on bone.
Osteoarthritis doesn't only affect the cartilage. It also affects the entire joint. It causes changes in the bone and weakens the strong bands of tissue that hold the joint together and attach muscle to bone. It also may cause swelling of the joint lining.
Factors that can increase your risk of osteoarthritis include:
Osteoarthritis is a disease that worsens over time, often resulting in chronic pain. Joint pain and stiffness can become severe enough to make daily tasks difficult.
Depression and sleep disturbances can result from the pain, stiffness and mobility issues of osteoarthritis.