The point at which the iliac and the sacrum meet is known as the sacroiliac (SI) joint. The SI joint is located in the lower back, just below the level of the hip bones on either side of the spine. The main role of the SI joint is to support the weight of the upper body and to help manage forces produced by both the upper and lower body. It is also surrounded by numerous ligaments to help hold it in place along with an even larger number of muscles which run to or from the SI joint spanning the back, buttocks and back of the leg (Cohen, 2018).

Differentiating SI joint pain from lower back pain

SI joint pain is often difficult to distinguish from lower back pain (Cohen, 2018; Laslet, 2008). In fact, SI joint pain can often lead to lower back pain. However, there are some unique characteristics to SI joint pain. If there is an area of maximal tenderness located around the upper back part of the hip bone, this may serve as a strong indicator for SI joint pain. Also, SI joint pain is usually unilateral (Cohen, 2018). There may be pain that occurs as a result of the SI joint but is located in a different area known as referred pain (Laslet, 2008). This referred pain may be felt in the buttocks, lower back, leg, or groin. Often times the pain can increase as you try to rise from a sitting position (Cohen, 2018; Hamidi-Ravari et al., 2014).

Causes of SI joint pain

SI joint pain occurs due to injury or pathology involving the structures composing the joint. Some of the common causes are cumulative strain such as jogging, uneven leg length, pregnancy, and injury to the ligaments of the SI joint (Al-Subahi et al., 2017; Cohen, 2018). Other causes are different types of arthritis. Osteoarthritis causes degeneration of the SI joint and consequently SI joint inflammation. Ankylosing spondylitis causes inflammation that affects the joints of the spine as well as the SI joint (Robinson et al., 2004).

Risk factors for SI joint pain

Risk factors for developing SI joint pain are: abnormal gait pattern, leg length discrepancy, obesity, heavy physical exertion, persistent strain/low-grade trauma (e.g. jogging), scoliosis, pregnancy, and sacral fusion surgery (Al-Subahi et al., 2017; Cohen, 2018). Muscle imbalances and a pelvic upslip, when one hip bone sits higher than the other, also increase the chance of developing SI joint pain.

Diagnosis of SIJ pain

As previously mentioned, the SI joint is surrounded by a number of structures any of which may be the source of your pain. As such, in order to confirm the presence of SI joint pain, a thorough assessment by a physiotherapist is required. This assessment will include a detailed history including past injuries along with a series of special tests. In the presence of SI joint pain, these special tests, otherwise known as provocative tests, will reproduce the pain that you feel (Robinson et al., 2004). Laslett (2008) has shown that if three or more of these tests in Figure 2 are positive by reproducing pain, then the chances of having true SI joint pain is 91%. These tests are necessary as they will be able to pinpoint the origin of the pain and rule out the other numerous structures surrounding the joint (Robinson et al., 2004). Once the SI joint has been identified as the source of the pain, your physiotherapist will be able to take the next steps towards alleviating the pain through stretches, exercises and postural changes.

Self-Management of SI Joint pain

During the acute phase of SI joint pain (1-3 days of first experiencing pain), it is recommended to avoid aggravating factors of the pain. The aggravating factors are specific to each individual, however common ones are running, skating, and any twisting movements. Your physiotherapist will assess whether an SI belt can help you. When appropriate and applied properly, these supports can reduce your pain and improve your function.  During the recovery phase (3 days – 8 weeks), it is recommended to seek physiotherapy and follow with prescribed home exercises (Hamidi-Ravari et al., 2014).

Benefits of Physiotherapy for SI Joint Pain

Physiotherapy intervention is effective for treating the sources of SI joint pain. The goals of physiotherapy for SI joint pain is to improve pelvic stability and symmetry and hence reducing the SI joint pain. Effective physiotherapy interventions are  manual manipulations to the SI joints and lumbar vertebrae, exercises for treating muscle strength imbalances, and postural education (Al-Subahi et al., 2017).

References

1. 1. Al-subahi, M., Alayat, M., Alshehri, A. M., Helal. O., Alhasan. H., Alalawi. A., Takrouni. A., Alfaqeh, A. (2017). The effectiveness of physiotherapy interventions for sacroiliac joint dysfunction: a systematic review. Journal of Physical Therapy Science. 29(9): 1689-1694.
   2. Cohen, S. P. (2018). Sacroiliac Joint Pain. Essentials of Pain Medicine, 601-612.e2. doi:10.1016/b978-0-323-40196-8.00066-8
   3. Hamidi-Ravari, B., Tafazoli, S., Chen, H., Perret, D. (2014). Diagnosis and current treatments for sacroiliac dysfunction: a review. Current Physical Medicine and Rehabilitation Reports. 2(1): 48-54. doi: 10.1589/jpts.29.1689
   4. Laslet, M. (2008). Evidence-based diagnosis and treatment of the painful sacroiliac joint. Journal of Manual and Manipulative Therapy. 16(3): 142–152, DOI: 10.1179/jmt.2008.16.3.142
   5. Overview – Sacroiliac Joint Clinic in Minnesota. (n.d.). Retrieved from https://www.mayoclinic.org/departments-centers/orthopedic-surgery/sacroiliac-joint-clinic/overview
   6. Review of the aetiology, diagnosis and management of sacroiliac joint disorders. (2016, March 31). Retrieved from https://www.spinalsurgerynews.com/2016/05/review-of-the-aetiology-diagnosis-and-management-of-sacroiliac-joint-disorders/13889
   7. Robinson, H. S., Brox, J. I., Robinson, R., Bjelland, E., Solem, S., & Telje, T. (2007). The reliability of selected motion- and pain provocation tests for the sacroiliac joint. Manual Therapy, 12(1), 72-79. doi:10.1016/j.math.2005.09.004