Osteoarthritis: Diagnosis

Diagnosis of osteoarthritis is based on a series of multiple tests. Doctors often begin by discussing a patient's family history and symptoms. A physical examination usually follows. The doctor checks the patient's reflexes and general health, including muscle strength. The doctor will also examine bothersome joints and observe the patient's ability to walk, bend, and carry out activities of daily living that involve the joints.

Other diagnostic tests include:

• X-rays. Doctors take x-rays to see how much joint damage has been done. X-rays of the affected joint can show cartilage loss, bone damage, and bone spurs. Unfortunately, x-rays cannot show early osteoarthritis damage before much cartilage loss has taken place.

• Magnetic resonance image (MRI). MRI's provide high-resolution computerized images of internal body tissues. This procedure uses a strong magnet that passes a force through the body to create these images. Doctors often use MRI tests if the patient experiences joint pain, if x-ray findings are minimal, and if tests suggest damage to other joint tissues such as a ligament.

• Other tests. The doctor may order blood tests to rule out other causes of symptoms. He or she may also order a joint aspiration, which involves drawing fluid from the joint through a needle and examining the fluid under a microscope.

It usually is not difficult to tell if a patient has osteoarthritis. It is more difficult to tell if the disease is causing the patient's symptoms. Osteoarthritis is so common-especially in older people-that symptoms seemingly caused by the disease actually may be due to other medical conditions, such as many rheumatologic conditions. The doctor will try to find out what is causing the symptoms by ruling out other disorders and identifying conditions that may make the symptoms worse.