Sacroiliitis is inflammation of one or both sacroiliac joints (SI joints) where the lower spine and pelvis connect. Sacroiliitis can cause pain in the lower back, buttocks, pelvis or hips and can extend down one or both legs. Pain can be worse with prolonged standing, sitting, or climbing stairs.
Sacroiliitis can be caused by trauma (like a car accident or a fall) or physical stress (like pregnancy). Nearly a third of patients who have had a surgical fusion of their lower back will develop SI joint pain due to increased stress on the joints. Treatments for sacroiliitis may include physical therapy, bracing, injections, medications, or surgery.