How is sacroiliac joint dysfunction diagnosed?
The first step in diagnosis is typically a thorough history and physical examination by a physician. The physician will ask questions to determine if there are any underlying disorders that could be causing the patient's pain. This can also help differentiate pain coming from the SI joints, lumbar spine, or hips. There are various tests a physician can perform during the physical examination that can help isolated the source of the pain. By placing your hips and legs in certain positions and applying pressure, the SI joints can be moved or compressed to identify them as a source of pain. Other portions of the examination are to exclude certain possibilities that could mimic sacroiliac disease.
The next step in diagnosis is often plain radiographs (X-rays). The patient may have X-rays of the pelvis, hips, or lumbar spine depending on what the physician finds on the history and physical examination. A computed tomography (CAT or CT) scan may also help in the diagnosis. A CT scan gives a more detailed look at the joint and bones. Both X-rays and CT scans can help identify sacroiliitis. This can appear as sclerosis in the joints. More severe wear in the joints can appear as erosion of the bone around the SI joints. These tests can also look for fusion of the SI joints. A (MRI) scan can also be helpful. This provides a better evaluation of the soft tissues, including muscles and ligaments. It can also identify subtle fractures that may not be seen on an X-ray. The MRI can identify inflammation in the SI joint by the presence of excessive fluid in the joint. A bone scan can be obtained to help isolate the source of your pain and can be used to identify bony abnormalities. The bone scan can identify areas of increased activity in the bone. This is a nonspecific test and can be positive in cases of arthritis, infection, fracture or tumors of bone.
Often the most accurate method of diagnosing SI joint dysfunction is by performing an injection that can numb the irritated area, thereby identifying the pain source. An anesthetic material can be injected along with a steroid directly into the SI joint. This is usually performed with the aid of an X-ray machine to verify the injection is in the SI joint. The anesthetic and steroid can help relieve the pain from inflammation that is common with SI joint dysfunction. The duration of pain relief is variable, but this is very useful to determine that the SI joint is the source of the pain.