Abstract and Introduction
The sacroiliac joint (SIJ) is a diarthrodial joint that has been implicated as a pain generator in approximately 10% to 25% of patients with mechanical low back or leg symptoms. Unique anatomic and physiologic characteristics of SIJ make it susceptible to mechanical stress and also create challenges in the diagnosis of SIJ pain. A variety of inciting causes for SIJ pain may exist, ranging from repetitive low-impact activities such as jogging to increased stress after multilevel spine fusion surgery to high-energy trauma such as in motor vehicle accidents. Similarly, wide variability exists in the clinical presentation of SIJ pain from localized pain or tenderness around the SIJ to radiating pain into the groin or even the entire lower extremity. No pathognomonic clinical history, physical examination finding, or imaging study exists that aids clinicians in making a reliable diagnosis. However, imaging combined with clinical provocative tests might help to identify patients for further investigation. Although provocative physical examination tests have not received reliable consensus, if three or more provocative tests are positive, pursuing a diagnostic SIJ injection is considered reasonable. Notable pain relief with intra-articular anesthetic injection under radiographic guidance has been shown to provide reliable evidence in the diagnosis of SIJ pain.
The etiology of low back pain is often difficult to determine, given overlapping clinical signs and symptoms originating from an enormous number of pathophysiologic and psychosocial causes. Investigators have shown that diagnostic studies, history, and physical examination can be combined to identify some cases and ascertain that approximately 10% to 25% of time, low back pain or leg pain originates from the sacroiliac joint (SIJ). However, in the absence of trauma, tumor, or metabolic diseases directly affecting the SIJ, its role in generating low back pain is difficult to diagnose. Understanding the anatomy, function, and biomechanics of this particular joint is important to understand the pathophysiology of SIJ dysfunction.
J Am Acad Orthop Surg. 2019;27(3):85-93. © 2019 American Academy of Orthopaedic Surgeons