To make the diagnosis, your doctor will take your medical history and perform a physical examination.
The first step in obtaining a diagnosis is answering a detailed set of questions about where, when and how your symptoms first occurred. Because no lab test can confirm osteoarthritis, these questions are used to eliminate other possibilities.
Here are some questions your doctor is likely to ask:
• Which joints are involved?
• What triggers your pain?
• When is the pain at its worst?
• Does anything provide relief?
• Have your joints been red and swollen?
• Do you have morning stiffness, and how long does it last?
• Have you had fever, chills or unexplained weight loss?
• What type of work do you do?
• What other medical conditions do you have?
• What medications are you taking?
During the physical examination, the doctor will ask you to walk, bend and move the joints of your hands, arms, legs, feet and spine. This will show how many joints are affected and whether the arthritis occurs symmetrically (in matching joints on both sides of the body). The physician may also need to check other organs, such as your skin, heart, lungs and eyes, and your digestion, because they can be affected by certain rheumatic diseases.
X-rays are not essential to confirm a diagnosis of osteoarthritis because changes may not be seen until later in the course of the disease. In most cases, your doctor will be able to make a diagnosis based solely on your medical history and the results of your physical examination. However, X-rays may be obtained to determine the extent of cartilage loss, bone damage, bone spurs and narrowing of the joint spaces.
The severity of osteoarthritis indicated on an X-ray and in a physical examination may be quite different, however. Some individuals whose X-rays show joint changes have no symptoms. Conversely, X-rays of some people who have multiple sore and stiff joints may show little joint damage.
Magnetic resonance imaging (MRI) provides a two-dimensional view of cartilage and other soft tissues. These images can help the doctor better detect abnormalities that occur in the early stages of osteoarthritis. However, changes may not be seen until later in the course of the disease.
When the diagnosis is unclear, your doctor may use a procedure called joint aspiration to obtain a sample of synovial fluid from the affected joint. The aspiration is performed by injecting a local anesthetic into the joint and then inserting a syringe and withdrawing a small amount of fluid. The fluid is then examined under a microscope to check for the number and type of white blood cells present. This information can help determine whether osteoarthritis or another condition is causing your joint symptoms.
If the doctor suspects that your joint symptoms may be due to rheumatoid arthritis or another type of rheumatic disease (such as gout or lupus), he or she may also order blood and urine tests.