Sacroiliac Joint Pain

What it is

The sacroiliac joint connects the sacrum to the pelvis on each side. It moves only a few millimeters, but when it's inflamed or moving poorly it produces stubborn pain low in the back — usually one-sided, often pointed to with one finger right over the joint.

Symptoms

• Pain below the beltline, on one side, sometimes into the buttock, groin, or upper thigh
• Worse with standing from a chair, climbing stairs, rolling in bed, or standing on one leg
• A feeling of the pelvis "catching" or being unstable
• Usually no numbness or tingling — that suggests a nerve instead

How we evaluate it

A cluster of physical exam maneuvers that stress the joint raises suspicion, but the confirmatory test is an image-guided SI joint injection with local anesthetic: if numbing the joint removes the pain, the joint is the answer. Imaging helps mainly to exclude other causes — SI joints often look normal on MRI even when they hurt.

Conservative care first

Pelvic girdle strengthening, manual therapy, a sacroiliac belt for some patients, and correcting contributing mechanics — a leg-length difference, a hip problem next door — resolve most cases without procedures.

Procedures that may be considered

The same image-guided injection used to diagnose the joint can treat it, pairing anesthetic with anti-inflammatory medication. For pain that keeps returning despite confirmed diagnosis and good rehab, lateral-branch radiofrequency ablation may be considered.

When surgery makes sense

Minimally invasive SI fusion exists and helps a carefully selected few — typically after clearly positive diagnostic blocks, failed comprehensive rehab, and a long, honest conversation. We refer to surgeons who do this work regularly when those boxes are truly checked.

Sources and further reading

Authoritative references on this topic, for patients who want to read further. These are educational resources, not medical advice.

• SI Joint Pain — North American Spine Society (KnowYourBack). Patient information.
• SI Joint Pain — AAPM&R (PM&R KnowledgeNow). Clinical reference.
• Sacroiliac Joint Dysfunction: Diagnosis and Treatment — American Family Physician, 2022. Clinical review.
• Sacroiliac Joint Pain — StatPearls (NCBI Bookshelf), 2023. Clinical reference.

Educational information only. This page describes sacroiliac joint pain in general terms. Your situation depends on your history, examination, and imaging — the specifics are worked out at a consultation, not from a web page.