The SI joint is composed of the sacrum bone and the two ileum bones on both sides. The sacrum is made up of five vertebrae which are anatomically fused together and the ileum forms the pelvis. The joint is held together by a large ligament. The primary function of this joint is to support the weight of the upper body in the standing position, the available range of movement is very little. Sacroiliac joint dysfunction happens when pain, injury or inflammation occurs.
Sacroiliac joint dysfunction can be caused by different conditions. As with other joints in the body, the sacroiliac joint can also be affected by arthritis. Osteoarthritis, an arthritic condition can occur when the cartilage of the joint becomes thinner. The bone will then rub with each other and could lead to arthritis, which is the number one cause of SI dysfunction. Other condition that may cause SI dysfunction is direct impact to the joint like in falls. Due to postural changes and abnormality in hormones brought about by pregnancy, SI dysfunction is common in pregnant women.
Abnormal kinematics in the joint can lead to pain, and this is true in people with leg length discrepancy, or when one leg is longer than the other. Systemic disorders may also affect the SI joint like gout, RA (rheumatoid arthritis), ankylosing spondylitis and psoriasis.
Pain in SI dysfunction is felt in the lower back region but can extend up to the buttocks. Intensity of pain increases when the back is extended like in walking, lying down or standing. Pain can be perceived in the hips and groin area. During physical examination, pain can be reproduced by giving stress to the joint.
Noninvasive treatment for SI joint dysfunction includes physical therapy. Invasive procedures include joint injections of local anesthetic and steroid. Lumbar stabilization techniques and stretching of the back are typical exercises that are beneficial for SI joint dysfunction patients.