The sacroiliac joint: an underappreciated pain generator.

The sacroiliac joint itself and the specific diagnosis of sacroiliac dysfunction are both underappreciated causes of pain in the low back, the pelvis, and the proximal lower extremities. An anatomically atypical synovial joint, its extensive innervation accounts for multiple modes of pain presentation. The joint and its associated ligament complex are subjected to rather constant and significant stresses. These combined factors contribute to the body of patients who present with low-back, buttock, proximal-thigh, and groin pain. Physical examination usually is an attempt to assess for presumed abnormal motion of the sacroiliac or to provoke discomfort by stressing that joint. Nonoperative treatment is usually physical therapy, and both diagnostic and therapeutic injection of the sacroiliac joint may be employed. Surgery is a treatment of last resort. There is a lack of long-term studies that address the natural history of this problem and its treatment.