The sacroiliac joint is prone to wear and inflammation causing pain. SIJ pain is a common cause of low back pain and/or buttock pain on one side or both with 15-25% of patients with low back pain being affected.he sacroiliac joint (SIJ) is located at the lower end of the spine (sacrum) and joins the spine to the pelvis (the iliac bones) on either side. There are differences between SIJ in men and women, specifically during their 20s-30s.