The sacroiliac joint is a large weightbearing joint in the posterior pelvis which is responsible for transmitting weight and forces between the upper body and the legs and is critical for stability of the pelvic girdle and spine. The sacroiliac joint is estimated to be the cause of low back pain in 10–62% (average 25%) of cases. Injuries to the SI joint can occur with simple movements such as picking up heavy objects, traumatic events such as car accidents or slipping and falling on ice, in addition to degeneration and some autoimmune inflammatory conditions. When pain is not controlled with conservative treatments, an injection of cortisone using x-ray or ultrasound guidance can be extremely beneficial in alleviating pain, inflammation, and improving mobility. Additionally, after injection, additional treatments such as physical therapy or manipulation are much better tolerated and more impactful.
