Newtown G.P's talk: Assessing the Sacroiliac Joint

  This is an In-service training lecture presented to the lovely G.P's of Church Street Medical Practice in Newtown Sydney.


Prevalence and Predisposing Factors

It is generally accepted that 10% to 25% of patients with persistent mechanical low back pain below L5 have pain secondary to sacroiliac joint pathology (Simopoulous et al 2012). Predisposing factors for SIJ pain include true and apparent leg length discrepancy, older age, inflammatory arthritis, previous spine surgery, pregnancy and trauma. Compared with facet-mediated and discogenic low back pain, individuals with SIJ pain are more likely to report a specific inciting event, and experience unilateral pain below L5.


Pain Location





Owing in part to its size and heterogeneity, the pain referral patterns of the SIJ are extremely variable.

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Differential diagnosis

Discogenic LBP and Radiculopathy

Piriformis syndrome

Hip Labral tear

Gluteal Trigger points


Facet joint sprain/arthritis

Spondyloarthropathies (AS, etc)


Anatomy and osteokinematics

The SIJ is classified as a

- diarthroidal synovial joint

- has 6 degrees of freedom


- Interosseous lig. and posterior SI lig.

- Long dorsal lig.

- Sacrotuberous lig.


posterior ligaments


35 muscles attach to the pelvis. Stabilisation of the lumbo-pelvic region is complex, however certain patterns of muscle activation have been shown to consistently occur.

Clinically the gluteus medius and maximus have been shown to be delayed in SIJ dysfunction (Hungerford, 2004). The change in muscle action is related to altered intra-pelvic, with an increased tendency to anteriorly rotate the innonimate during weight bearing.


Assessing the SIJ

One of the simplest methods of assessing the SI joint is palpation.  However, the reliability and validity of palpating the SI joint has come into question in recent years.  Several studies have been published showing poor inter-tester reliability for SI joint palpation, including a study from Holgren and Waling.

McGrath has published an article, entitled “Palpation of the sacroiliac joint: an anatomical and sensory challenge” in which the concept of SI joint palpation is scrutinized.

Freburger and Riddle performed a literature review looking at our ability to perform SI joint motion testing.  They found poor inter-tester reliability, low sensitivity, and low specificity in several commonly performed tests. Another study from Robinson et al had similar conclusions, stating that SI joint motion palpation tests have poor inter-tester reliability. Riddle and Freburgers study noted that the ability to detect positional faults of the SI joint also has poor reliability.

Thus it appears that the reliability and validity of assessing SI joint symmetry and motion may be too poor to be used clinically.


Two of the best recent studies by Laslett et al and Van der Wurff et al have demonstrated that there probably isn’t one perfect SI joint provocative test that we can perform to definitively diagnose SI joint pain or dysfunction. However, by performing several tests in the same assessemnt, you can increase your sensitivity and specificity of detecting SI joint dysfunction.

Both Studies describe 5 key provocative tests to perform when attempting to diagnose SI joint pain:

  1. Gaenslen
  2. FABER / Patrick’s test
  3. Thigh thrust / femoral shear test
  4. ASIS distraction (supine)
  5. Sacral compression (sidelying)

Laslett et al report that the accuracy of detecting SI joint dysfunction is increased with at least 3 of the 5 tests are positive.  Furthermore, if all 5 tests are negative, you can likely look at structures other that the SI joint.  Van der Wurff et al report that if at least 3/5 of these tests were positive, there was 85% sensitivity and 79% specificity for detecting the SI joint as the source of pain.  Interestingly, another study by Kokmeyer et al agreed with the previous findings, but also noted that the thigh trust test alone was almost as good at detecting SI joint dysfunction as the entire serious performed together.

Harrison Vaughn’s You Tube videos are a great resource for learning the above clinical test (see below)

Gaenslen Test



FABER / Patrick Test



Thigh Thrust / Femoral Shear Test



ASIS Distraction



Sacral Compression




Physiotherapy - why has this happened? Is it trauma? Pregnancy? Is it biomechanics. A later blog will delve into treatment options.

Moderate to severe pain - Evidence supports both intra- and extra-articular causes for SIJ pain, with clinical studies demonstrating intermediate-term benefit for both intra- and extra-articular steroid injections (Cohen et al, 2013).


Go Go Physio is available for treatment of clients in Newtown and other surrounding suburbs.