Sacroiliac (SI) joint problems require appropriate interpretation of a patient’s history, clinical exam results, and imaging studies. Differential diagnostic approach, including the SI joint, the spine, and the hip, must be used to accurately assess and identify the actual pain generator(s).
During physical exam, patients with sacroiliac (SI) joint pain may exhibit any/all of the following symptoms:
- Low back pain
- Palpable tenderness of the posterior pelvic sacroiliac (SI) region
- Pain from provocative maneuvers to the hip (i.e. Faber test) and the absence of neurologic deficit
- Joint asymmetry as seen on CT and MRI.
When the SI joint is suspected as the source of the patient’s low back pain, confirmation is provided by CT or fluoroscopic guided injection. This injection is the diagnostic "litmus test." If lidocaine is injected into the joint and symptoms temporarily resolve, this is confirmation of the SI joint as the source, or a source, of the patient’s low back pain (as multiple pain generators may co-exist).
Evaluating the SI Joint
A comprehensive approach to SI joint evaluation might look like this:
- Recognize patient history of SI joint problems
- Perform physical examination:
- Provocative tests (minimum 3 out of 5 tests should be positive)
- Review or order imaging studies – for abnormalities / asymmetry
- Administer diagnostic injections
Basics of the SI Joint Exam
Provocative Tests for Sacroiliac (SI) Joint Disorders
After assessing the patient for existence of tenderness upon palpation, there are a series of provocation tests that will generate pain in patients with SI joint problems and should be included in the examination. The rule of thumb for a positive diagnosis of the SI joint as a pain generator is pain provoked in at least 3 out of 5 of the following tests:
Diagnosing SI Joint Disorders: Provocative Testing
Applies tensile forces on the anterior aspect of the SI joints
- The patient lies supine and is asked to place their forearm under their lower back to maintain lordosis and to support the lumbar spine.A pillow is placed under the patient’s knees. The examiner places their hands on the anterior and medial aspects of the patient’s left and right ASIS with arms crossed and elbows straight.
- A slow and steady posterior force is applied by leaning down toward the patient.
Applies anteroposterior shear stress on the SI joint
- The patient lies supine with affected side hip flexed to 90 degrees. The pelvis is stabilized at the opposite ASIS with the hand of the examiner.
- The examiner stands on the same side as the flexed leg. The examiner provides steady increasing pressure through the axis of the femur.
FABER - (Flexion, ABduction, External Rotation)
Applies tensile force on the anterior aspect of the SI joint on the side tested
- The patient lies supine as the examiner crosses the affected-side foot over the opposite-side thigh. The pelvis is stabilized at the opposite ASIS with the hand of the examiner.
- A gentle downward force is applied to the affected-side knee of the patient and is steadily increased, exaggerating the motion of hip flexion, abduction, and external rotation.
Applies compression force across the SI joints
- The patient is placed in a side-lying position, with the affected side up, facing away from the examiner, with a pillow between the knees.
- The examiner places a steady downward pressure through the anterior aspect of the lateral ilium, between the greater trochanter and iliac crest.
Applies torsional stress on the SI joints
- The patient lies supine with the affected side leg near the edge of the table. For safety, the patient’s shoulders are positioned towards the middle of the table.
- The patient then draws the non-affected side leg into full flexion and holds the flexed knee. The examiner stabilizes the leg with their hand placed over the patient’s hand. This action keeps the ilium on the non-tested side in a slightly posterior and stable position during the maneuver.
Diagnostic SIJ injection
If, following the injection, the patient's pain is decreased a significant amount, then it can be concluded that the SI joint is either the source, or a major contributor, to the low back pain.1
- Posterior & inferior approach
- 22 gauge 5" styletted needle
- 0.25ml contrast medium
- 1.25ml Lidocaine
1. Dreyfuss, Paul et al. "Sacroiliac Joint Pain." J Am Acad Orthop Surg 2004;12:255-265.
Sacroiliac (SI) Joint Injection Technique
The most common means for confirming sacroiliac joint disorders is an injection with CT or fluoroscopic guidance to confirm accurate placement of the needle into the SI joint. The pain response indicates the role of the SI joint in each case:
- If no pain improvement, then test was negative. SI joint is not a pain generator.
- If > 50% pain improvement, then test was positive. SI joint is considered a pain generator.
Diagnosing SI Joint Disorders: Diagnostic Injection Demonstration
Reference Tools--Print out the following resources to aid in your diagnosis of Sacroiliac (SI) Joint Disorders:
- Management Algorithm For SI Joint Complaints
- Recommended Sacroiliac Joint Injection Technique (two-page article)
If your patients have low back symptoms that are SI joint in origin, learn more about SI joint disorders and using a minimally invasive surgical (MIS) approach called the iFuse Implant System®.
The iFuse Implant System® is intended for sacroiliac joint fusion for conditions including sacroiliac joint dysfunction that is a direct result of sacroiliac joint disruptions and degenerative sacroiliitis. The iFuse Implant System® is intended for sacroiliac fusion for conditions including sacroiliac joint dysfunction that is a direct result of sacroiliac joint disruption and degenerative sacroiliitis. This includes conditions whose symptoms began during pregnancy or in the peripartum period and have persisted postpartum for more than 6 months. There are potential risks associated with the iFuse Implant System. It may not be appropriate for all patients and all patients may not benefit. For information about the risks, click here.