From the Guidelines
Sacroiliac (SI) joint pain is primarily caused by mechanical stress, inflammation, and structural lesions.
Causes of SI Joint Pain
- Mechanical stress, such as physically demanding activities (e.g., soccer, riding, long-distance running) or a history of childbirth, can lead to bone marrow oedema and specific structural lesions in the SI joints 1.
- Inflammatory conditions, such as axial spondyloarthritis (axSpA), can also cause SI joint pain, characterized by symptoms like morning stiffness, pain that improves with exercise but not rest, and alternating buttock pain 1.
- Structural lesions, including bone erosion, new bone formation, sclerosis, and fat infiltration, can also contribute to SI joint pain 1.
Diagnostic Considerations
- Imaging studies, such as conventional radiography and MRI, are essential for diagnosing sacroiliitis and axSpA, with MRI being more sensitive for detecting inflammatory lesions and structural changes 1.
- A combination of clinical findings, biologic data (e.g., HLA-B27, C-reactive protein), and imaging findings is often used to diagnose axSpA 1.
- In cases where radiographs and MRI of the SI joints are negative, further imaging of the spine may be helpful to support diagnosis and guide treatment 1.
From the Research
Causes of Sacroiliac (SI) Joint Pain
The Sacroiliac (SI) joint is a complex joint in the region of the posterior pelvis, formed by the sacrum and the ilium bones, and its dysfunction can cause low back pain, with or without pseudo-radicular pain in the legs 2, 3, 4, 5, 6. The causes of SI joint pain can be attributed to various factors, including:
- Trauma, pregnancy, or certain athletic activities, which can lead to SI joint dysfunction 3
- Anatomical variants of the SI joint, such as additional extra-articular secondary joints or ossification centers, which can be observed in CT scans 2
- Innervation of the SI joint, which can lead to pain generation, with dorsal innervation from lateral branches of the dorsal rami of the spinal nerves S I-S III 2
- Mechanical stress on the SI joint and its surrounding ligaments, which can cause pain and discomfort 4
- Individual factors, such as pelvic anatomy and functionality, which can contribute to SI joint pain 2, 5
Diagnosis and Treatment of SI Joint Pain
Diagnosing SI joint pain can be challenging, but a complete history and physical examination, including provocative maneuvers and diagnostic injections, can help confirm the diagnosis 5, 6. Treatment options for SI joint pain include:
- Conservative management, such as patient education, pelvic girdle stabilization, and manipulative therapy 5
- Interventional treatment options, including intra-articular corticosteroid injections, cooled radiofrequency ablation, or SI joint fusion 5, 6
- Diagnostic SI joint blocks, which can help confirm the diagnosis and guide treatment 6