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Am Fam Physician. 2022;105(3):239-245

Patient information: See related handout on sacroiliac joint dysfunction and back pain, written by the authors of this article.

This clinical content conforms to AAFP criteria for CME.

Author disclosure: No relevant financial relationships.

Sacroiliac (SI) joint dysfunction is a common cause of low back pain and accurate diagnosis can be challenging. A complete history and physical examination are critical in differentiating other diagnoses that may have similar signs and symptoms. Positive responses to at least three physical provocation tests suggest SI joint dysfunction, and local anesthetic SI joint blocks can also be useful for confirming the SI joint as the source of pain. Conservative treatment consists of a multimodal program combining patient education, pelvic girdle stabilization with focused stretching, and manipulative therapy. These programs can be performed by physical therapists or clinicians trained in manipulative therapy. Pelvic belts may be beneficial in affected postpartum patients. Patients with symptoms that do not improve with conservative management may benefit from interventional treatment options including intra-articular corticosteroid injections, cooled radiofrequency ablation, or SI joint fusion.

The prevalence of sacroiliac (SI) joint dysfunction is approximately 25% in adult patients with chronic low back pain.1 Pain can be unilateral or bilateral but usually not midline.2 Women are more likely to present with SI joint dysfunction than men.3 The SI joint in women is more mobile compared with the SI joint in men, resulting in larger stress, load, and pelvic ligament strain.4 SI joint dysfunction is common in pregnant and postpartum patients.5

Etiology and Differential Diagnosis

The SI joint serves as a shock absorber and transfers vertical loads from the lumbar spine to the lower extremities during bending movements. The etiology of SI joint dysfunction is not well understood. The SI joint may be the primary source of pain, or dysfunction at the joint or surrounding structures may affect the joint’s load transfer function and produce a painful stimulus.6

SI joint dysfunction can be associated with osteoarthritis or inflammatory conditions such as ankylosing spondylitis, posttraumatic arthritis, and other spondyloarthropathies.7 Similarly, mechanical faults at the pubic symphysis or SI joint can result in pelvic asymmetry or joint instability. Nonoptimal load transfer is seen in patients with SI joint stiffness (hypomobility) and patients with insufficient pelvic girdle stability (hypermobility).8 Table 1 presents the differential diagnoses of conditions with similar or overlapping signs and symptoms of SI joint dysfunction.911

Differential diagnosisClinical presentation
Femoral acetabular impingementPain with activity or prolonged sitting, joint locking or clicking
Fractures (secondary to trauma, osteoporosis)History and imaging
InfectionFever, malaise, intractable pain
Ischiofemoral impingementGluteal or hip pain, hip snapping, shortened stride
Lumbar disc herniationNumbness or tingling in the legs or feet, lower extremity weakness, radiating pain, bowel or bladder changes
Lumbar facet syndromeOlder age, paraspinal muscle tenderness, pain with backward bending
Piriformis syndromeSitting intolerance, radiating pain along the posterior of one or both legs
Pudendal nerve irritationPerineal or scrotal pain, sitting intolerance
SpondyloarthropathiesPositive findings on laboratory tests, diagnostic imaging
TumorFocal bone pain, pathologic fractures

History and Physical Examination

Differentiating SI joint dysfunction from other diagnoses presenting with low back pain requires a complete history and physical examination of the spine, pelvic girdle, and hips as well as a review of other systems to rule out red flags such as history of trauma, unexplained weight loss, fever, bowel and bladder changes, cancer, and night pain.6,12,13

Patients with SI joint dysfunction may present with pain that is localized to the area at or just inferomedial to the posterior superior iliac spine as demonstrated in a Fortin finger test (Figure 1) or along the gluteal area, lateral hip, lower extremities, and groin.2,12 Potential aggravating factors and activities that may exacerbate pain from SI joint dysfunction are described in Table 2.3,12

Ascending or descending stairs
Jogging uphill
Landing after jumping
Lying on the affected side
Prolonged sitting in a car
Prolonged standing
Shifting weight to the affected side
Turning in bed

SI joint dysfunction may be attributed to a variety of causes.12 Traumatic onset commonly occurs with heavy lifting, a fall onto the buttocks, and motor vehicle collisions. A more insidious onset can be caused by recreational activities with repeated weight bearing and shear or torsional forces experienced during sports such as football, gymnastics, and golfing.

A physical examination should include gait analysis (i.e., reporting of pain with walking, shortened stride length, antalgic gait), range of motion, provocation testing, strength, flexibility, and palpation assessments (Table 3).2,3,12,1416 Lower extremity neurologic screening (i.e., reflexes, sensation, strength, straight leg raise) is helpful when considering differential diagnoses.

ComponentFindings or physical examination response
ObservationAsymmetric iliac crest height
Asymmetric weight-bearing when standing
GaitPainful catching or increased pain ipsilaterally during stance phase
Decreased hip extension resulting in shortened contralateral stride length
Provocation testsThree of five positive tests suggest sacroiliac joint dysfunction (Figures 2 through 6)
Strength testingGluteus medius weakness
FlexibilityIliopsoas tightness
Piriformis tightness
Hamstring tightness with gluteal weakness
PalpationReported pain at or inferomedial to the posterior superior iliac spine

Motion and provocation tests can assess the SI joint for dysfunction and pain reproduction6,17 (Figure 2Figure 3Figure 4Figure 5, and Figure 6). A video demonstration is available at

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