By Ted Findlay, MD, DO, CCFP
The sacro-iliac (say: sey-kroh-IL-ee-ak) joint can be one of the causes of mechanical low back pain. It is often seen with other causes of low back pain. The sacro-iliac joint lies between the sacrum and the iliac crests of the pelvic bones. The sacrum is the bone at the bottom of your spine just above the tailbone. It looks somewhat like a keystone or an upside down pyramid. You can find it just below your beltline. The sacro-iliac joint moves slightly when you walk. Its normal function relies on the muscles and ligaments that cross the joint.
Signs and symptoms
Patients with sacro-iliac joint pain often complain of pain not only over the low back and hip, but often into the buttock and often into the groin on the same side. It can be painful to sit for longer periods of time, to get out of a chair, or to climb stairs. Patients also often complain of pain with bending and lifting.
Sacro-iliac joint pain can come on in the absence of any clear injury. More commonly, it follows trauma such as a slip and fall. It can happen after a motor vehicle accident when the foot on the same side has been braced on the brake pedal. This may result in a rear force across the pelvis. It may be related to abnormal biomechanical forces across the low back that may be the result of a postural abnormality. One example of a postural abnormality is a shorter or longer leg. It can follow twisting forces applied across the low back and pelvis especially when lifting. It can be the result of dysfunction of the muscles that cross the joint such as the piriformis muscle, or ligaments that are injured or too loose.
Sometimes, sacro-iliac joint pain can be related to an arthritic condition such as ankylosing spondylitis. In these cases there is often a family history of similar problems.
Sacro-iliac joint pain and dysfunction is most often diagnosed based upon the history and physical exam tests performed by a physician or qualified health care provider. Other causes of back pain need to be looked for as well. Sometimes X-rays or more specialized imaging or blood tests may be used to rule out other causes of pain including ankylosing spondylitis.
Hot and cold packs
Self-treatment in the first few days includes the use of topical cold packs such as ice or gels applied for not longer than 15 to 20 minutes at a time. After 48 to 72 hours, hot packs may feel more comfortable or be alternated with the cold.
Over-the-counter medicines such as acetaminophen or ibuprophen can be helpful, if you are sure that these medicines are safe in your case. Your physician may prescribe other anti-inflammatory or pain medicines.
Mobilization (moving) of the sacroiliac joint by a qualified manual therapy provider such as a physiotherapist, chiropractor, osteopathic physician, or other qualified physician, may be helpful. Shoe inserts or orthotics may be useful if you have a short leg.
Sometimes, a doctor will recommend injections of the sacroiliac joint with cortisone (for inflammation) or other agents (for instability).
Besides stretches of the hamstring and quadriceps muscles, flexion stretches that involve lying on your back and flexing one knee to both the same and opposite shoulder can be helpful. This is followed by flexing both knees to the shoulders. Many people find that using a bicycle or exercise to strengthen the related muscles is helpful. Others find this increases pain in the related muscles.
American Pain Foundation
TRIP Database (Resources for Evidence Based Medicine)