Osteoarthritis is the most common form of arthritis, affecting millions of people worldwide. It occurs when the protective cartilage that cushions the ends of your bones wears down over time.

Although osteoarthritis can damage any joint, the disorder most commonly affects joints in your 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 some treatments might slow progression of the disease and help improve pain and joint function.

Osteoarthritis symptoms often develop slowly and worsen over time. Signs and symptoms of osteoarthritis include:

• Pain. Affected joints might hurt during or after movement.
• Stiffness. Joint stiffness might be most noticeable upon awakening or after being inactive.
• Tenderness. Your joint might feel tender when you apply light pressure to or near it.
• Loss of flexibility. You might not be able to move your joint through its full range of motion.
• Grating sensation. You might feel a grating sensation when you use the joint, and you might hear popping or crackling.
• Bone spurs. These extra bits of bone, which feel like hard lumps, can form around the affected joint.
• Swelling. This might be caused by soft tissue inflammation around the joint.

When to see a doctor

If you have joint pain or stiffness that doesn’t go away, make an appointment with your doctor.

Causes

Osteoarthritis occurs when the cartilage that cushions the ends of bones in your joints gradually deteriorates. Cartilage is a firm, slippery tissue that enables nearly frictionless joint motion. Eventually, if the cartilage wears down completely, bone will rub on bone.

Osteoarthritis has often been referred to as a “wear and tear” disease. But besides the breakdown of cartilage, osteoarthritis affects the entire joint. It causes changes in the bone and deterioration of the connective tissues that hold the joint together and attach muscle to bone. It also causes inflammation of the joint lining.

Risk factors

Factors that can increase your risk of osteoarthritis include:

• Older age. The risk of osteoarthritis increases with age.
• Sex. Women are more likely to develop osteoarthritis, though it isn’t clear why.
• Obesity. Carrying extra body weight contributes to osteoarthritis in several ways, and the more you weigh, the greater your risk. Increased weight adds stress to weight-bearing joints, such as your hips and knees. Also, fat tissue produces proteins that can cause harmful inflammation in and around your joints.
• Joint injuries. Injuries, such as those that occur when playing sports or from an accident, can increase the risk of osteoarthritis. Even injuries that occurred many years ago and seemingly healed can increase your risk of osteoarthritis.
• Repeated stress on the joint. If your job or a sport you play places repetitive stress on a joint, that joint might eventually develop osteoarthritis.
• Genetics. Some people inherit a tendency to develop osteoarthritis.
• Bone deformities. Some people are born with malformed joints or defective cartilage.
• Certain metabolic diseases. These include diabetes and a condition in which your body has too much iron (hemochromatosis).

Complications

Osteoarthritis is a degenerative 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 and disability of osteoarthritis.