Doctors can sometimes diagnose osteoarthritis by a medical history and a physical examination alone. Tests or X-rays may be helpful if the doctor:
- has trouble determining the diagnosis
- needs to confirm a diagnosis
- needs to rule out other bone, joint, or muscle conditions
When do I need an X-ray?
X-rays show changes in the joint's structure and can show spurs. Just about every person age 75 and older shows X-ray changes in at least one joint. Many people will show joint changes on X-ray without ever having symptoms. Even without symptoms, osteoarthritis can be present.
What will an X-ray show?
What your doctor sees on your joint X-rays depends on how severe your osteoarthritis is and which joint is affected. The most common findings are bony growths called osteophytes or spurs. These occur at the point where ligaments and muscle attach to the bone. Your doctor may also see the following:
- Narrowing of the joint space. As the cartilage wears away, the joint begins to lose its normal shape, and the space between the bones narrows.
- The formation of cysts. When osteoarthritis worsens and areas of the cartilage disappear, fluid-filled cysts often form in the bone and near the joints.
- A change in the shape of the bone. As the cartilage wears away, the bone beneath it is exposed to the stress placed on the joint. This causes new bone to form and changes the overall shape of the joint. Usually, the reformed joint is larger and thicker than a normal one.