Sacroiliac Joint Pain (SIJ Pain): Symptoms, Treatment and Exercises

15–30%Estimated share of low back pain cases in which the sacroiliac joint is the source

3 × 10 cmThe area where the pain usually sits: just below the bony bump at the upper back of the pelvis

The very bottom of the backPain from this joint usually does not go higher than the level of the last lumbar vertebra

Several testsThe diagnosis is made by looking at several examination tests together, not a single test

Symptoms

Pain at the very bottom of the back, usually on one side, at the upper back of the hip.
Pain that can spread to the buttock, groin, back of the thigh or even the leg; it can resemble sciatica.
Pain that gets worse when getting up from a chair or after sitting for a long time.
Sometimes a feeling that the leg might give way, or tingling.

What causes it?

A hard fall onto the buttocks, or repeated strain.
Pregnancy, as the joint ligaments loosen. You can look at the back and pelvic pain in pregnancy guide.
Leg length difference, walking problems, scoliosis and long-term intense sport.
Having had a fusion operation on the lower back.
Rheumatic conditions that inflame the joint, such as ankylosing spondylitis.

What can I do at home?

Try to stay active and carry on with your daily activities as far as you can.
You can avoid sitting for long periods, get up often and take short walks.
Ice or painkillers may bring relief; you can ask your doctor or pharmacist before taking medicines.
You can strengthen the muscles that stabilise the pelvis with the exercises below.

Treatment options

Exercise and physiotherapy: Pelvic stabilisation exercises are the first step.
Belt: It gives support for some people; results vary.
Injections: Injections into or around the joint can help with both diagnosis and treatment.
Radiofrequency and surgery: Considered for selected people whose pain has not responded to other treatments for a long time.

Exercises at home

Six exercises to stabilise the pelvis

Do the movements slowly and with control, within a pain-free range. If a movement clearly increases the pain around the joint, you can skip it for a while and carry on with the others.

Pelvic tilt

Lie on your back with your knees bent and your feet flat on the floor. Gently tighten your stomach and press the hollow of your lower back down towards the floor; hold for 5 seconds, then relax. Do not hold your breath.

10 reps, twice a day

Bridge

Lie on your back with your knees bent and feet flat on the floor. Squeeze your buttocks and lift your back off the floor so that your shoulders, hips and knees form a straight line. Hold for 3–5 seconds, then lower slowly.

10–15 reps, 1–2 times a day

Bird dog

Get on your hands and knees with your back flat. Reach your right arm forwards and your left leg back, without letting your lower back arch or your hips rotate. Hold for 5 seconds, then repeat with your left arm and right leg.

8–10 reps on each side

Side-lying leg raise

Lie on your side with the lower knee slightly bent. Lift the top leg with the knee straight and the toes pointing forward; do not let your hip roll backwards. The muscles at the side of the hip help keep the pelvis steady.

10–15 reps on each side

Knee to chest

Knee-to-chest stretch

Lie on your back. Hold one knee with both hands and slowly pull it towards your chest until you feel a gentle stretch in your lower back. If you like, gently lift your head towards your knee as you pull, keeping your shoulders on the floor (as in the Williams exercises); if you have neck pain, keep your head on the floor. Then repeat with the other leg.

Hold for 20–30 seconds, 3 times on each leg

Brisk walking

Walking

Wear comfortable shoes and walk at a pace and for a length of time the pain allows. If sitting for long periods makes the pain worse, spread short walks through the day.

Start with 5–10 minutes and add a few minutes each week

Frequently asked questions

Where is the sacroiliac joint?

It lies between the triangular bone at the bottom of the spine (the sacrum) and the pelvis, on both sides of the lower back, just below the two small dimples at the upper back of the hips. It transfers the weight of the body to the legs and moves very little.

How can you tell the pain is coming from this joint?

It is not easy. The pain is very similar to pain from the lower back, the hip or the sciatic nerve. No single examination test or scan gives a definite answer; doctors look at several pain provocation tests together. The most reliable method is usually to inject a local anaesthetic into the joint and see whether the pain goes away.

Does a belt help?

Sacroiliac belts are among the options used alongside exercise, physiotherapy and injections, but results vary from person to person. You can assess whether a belt works for you together with a physiotherapist.

Will I need surgery?

For very few people. A fusion operation is considered for pain that has not settled despite at least 6 months of non-surgical treatment and has been shown by tests and a diagnostic injection to come from the joint. For some people, radiofrequency treatment, which uses heat to switch off the nerve endings, can bring relief lasting 6–12 months.

For similar pain, you can look at the low back pain and piriformis syndrome guides.

When should you see a doctor?

If the pain does not ease within a few weeks or keeps getting worse
If you have back and buttock pain that started at a young age, comes with long-lasting morning stiffness and eases with movement (it could be a rheumatic condition)
If it started after a fall or a blow
If it comes with fever, unexplained weight loss or a history of cancer
Urgent: if you have weakness or numbness in both legs, numbness around the groin and buttocks, or problems controlling your bladder or bowels

Sources

Barros G, McGrath L, Gelfenbeyn M. Sacroiliac joint dysfunction in patients with low back pain. Federal Practitioner. 2019;36(8):370–375.
HCA Healthcare UK. Sacroiliac (SI) joint pain.
National Institute for Health and Care Excellence. Low back pain and sciatica in over 16s: assessment and management (NG59). London: NICE; 2016, updated 2020.