Sacroiliac (SI) joint pain: low back and buttock pain from the pelvis

What is SI joint pain?

The SI joints are strong, stable joints that move only a little. They transfer weight between your upper body and legs. Pain can come from the joint itself or the strong ligaments around it. You may see it called SI joint dysfunction, or sacroiliitis when the joint is inflamed.

Possible causes include:

• falls or other injuries
• changes during pregnancy and after childbirth
• wear in the joint with age
• differences in how you walk or load your legs
• inflammatory conditions such as ankylosing spondylitis

Symptoms

• pain low in the back on one side, near the dimple above the buttock
• pain in the buttock, sometimes spreading into the back of the thigh
• pain that's worse when standing on one leg, climbing stairs, getting out of a car, or turning in bed
• stiffness after sitting

Because these symptoms overlap with disc, facet and hip problems, careful assessment is important.

When back pain is an emergency

See a doctor if you have long-lasting back and buttock pain with morning stiffness that improves with activity, especially if it started before age 45. This can be a sign of an inflammatory condition.

How it's diagnosed

Diagnosing SI joint pain is tricky. A 2021 review found that groups of physical tests for the SI joint are much better at ruling it out as the source of pain than at confirming it, and the certainty of that evidence was very low. Scans don't reliably show SI joint pain either.

So your physiotherapist combines your symptoms, a set of SI joint tests, and checks of your lower back and hips to work out what's most likely driving your pain. Any MRI, X-ray or lab reports you bring are reviewed.

You'll get a physiotherapy diagnosis and a personalised plan. You don't need a scan to book; if one would help, your physiotherapist will recommend an MRI or X-ray.

→ What happens at your spine assessment

What the research says

Diagnosis. As above, physical tests are better at ruling out the SI joint than confirming it, with very low certainty of evidence.

Treatment. A 2022 review in American Family Physician describes SI joint dysfunction as a common cause of lower back pain and recommends starting with a multi-part conservative programme that includes physical therapy exercise. Injections or other procedures by a doctor are options if this doesn't help.

Exercise. For long-lasting low back pain in general, a 2021 Cochrane review found moderate-certainty evidence that exercise probably reduces pain by an amount that makes a real difference to patients.

Practical tips

• Keep active, within comfort.
• Avoid standing on one leg for long, and step up stairs one at a time if they're painful.
• Sleep with a pillow between your knees if lying on your side is uncomfortable.
• Build strength gradually with your home programme.

These are general tips, not a substitute for an assessment.

When to book a spine assessment

Book an assessment if pain low in your back or buttock has lasted more than a few weeks, keeps coming back, or limits your daily life. Spine assessments are available at all five Maana Spine clinics in Kochi, Kozhikode, Thiruvananthapuram, Aluva and Perinthalmanna. The consultation fee is ₹250, and no doctor's referral is needed.

Book a Spine Assessment · or call or WhatsApp +91 99950 09403