FAQs on SI Joint Pain

Understanding sacroiliac (SI) joint pain means understanding the low back anatomy. There are two SI joints in the body. These are tiny triangle-shaped bones at the lower portion of the spine, where the spine affixes to the pelvis. SI joint pain occurs from loss of cartilage, which is a linking and shock absorber of the body.

What do the SI joints do?

Sacroiliac joints cushion the spine and offer body stability when you walk, run, or jump. The SI joints only move a few millimeters, but they allow for spinal movement. Each SI joint contains several nerve endings that cause significant pain when the joint is damaged, loses cartilage, or cannot move properly.

What causes SI joint pain?

Everyday wear-and-tear and age creates arthritis of the sacroiliac joints. In addition, an injury may damage one or both joints, altering normal movement and creating a chronic pain state. Chronic SI joint pain originates from a problem with one or both SI joints, and this lasts for three months or longer. A connection between the lower back and the symptoms can create sacroiliac joint dysfunction.

How common is SI joint pain?

The cause of chronic low back pain involves the sacroiliac joints around 20% of the time. This number increases to 30% when patients have had a previous back surgery, such as a lumbar fusion.

What are the symptoms associated with SI joint pain?

The most common symptoms associated with the SI joint include:

  • Low back pain – Typically described as a dull ache on one side of the lower back. This pain often radiates to the thigh.
  • Buttock pain – The pain may be felt in the buttock region, and the pain is often associated with a sharp, stabbing sensation that shoots down one or both legs.
  • Pain with climbing stairs – This activity requires the pelvis to twist.
  • Trouble sitting or lying on one side – The pain is often experienced as an ache on one side, and this causes the patient to shift weight to relieve discomfort.

How is SI joint pain diagnosed?

The first steps of diagnosing SI joint pain include a thorough history, medical examination, and diagnostic imaging tests, such as x-rays and magnetic resonance imaging scans. The doctor may require blood tests and a urinalysis to rule out certain conditions.

How is sacroiliac joint pain treated?

Treatment of SI joint pain involves:

  • SI joint belts – Also called a sacral belt, this device stabilizes the SI joint. These belts are 6-8 inches wide, support around the lower pelvis, and are lightweight.
  • Medications – To reduce inflammation and pain, first-line treatment involves nonsteroidal anti-inflammatory drugs (NSAIDs), such as naproxen and ibuprofen. Narcotic analgesics, such as hydrocodone and tramadol, are used short-term for severe low back discomfort.
  • Physical therapy – The therapist uses many modalities for pain relief, such as heat packs, ultrasound, and electrical stimulation. The therapist will instruct the patient on strengthening and flexibility activities also, to prevent further SI joint damage and alleviate pain.
  • SI joint injections – The doctor can inject one or both SI joints with a corticosteroid and/or a long-acting anesthetic agent. These medicines help to alleviate pain and inflammation. Ultrasound or x-ray guidance is used to verify correct needle placement. A recent clinical study found SI injections to have an 89% success rate.
  • Radiofrequency ablation – Using x-ray guidance, the doctor inserts a special needle into the SI joint and positions it near the affected nerve. Heat is emitted from the tip to temporarily destroy the nerve. This blocks pain signals to the brain from the SI joint. In a clinical study involving 50 people, most patients reported at least 50% pain relief or better following a radiofrequency ablation for lumbosacral radicular pain. The researchers reported that this procedure was both effective and safe for long-term palliative management of low back pain with radiculopathy.


Nagda JV, Davis CW, Bajwa ZH, & Simopoulos TT (2011). Retrospective review of the efficacy and safety of repeated pulsed and continuous radiofrequency lesioning of the dorsal root ganglion/segmental nerve for lumbar radicular pain. Pain Physician, 14(4), 371-376.

Sahin O, Harman A, Akgun, RC, & Tuncay IC (2014). An Intraarticular Sacroiliac Steroid Injection Under the Guidance of Computed Tomography for Relieving Sacroiliac Joint Pain: A Clinical Outcome Study with Two Years of Follow-Up. Archives of Rheumatology, 27(3). DOI: 10.5606/tjr.2012.028