Sacroiliac Joint Pain

Overview

The sacroiliac joints connect the base of the spine (the sacrum) to the pelvis on each side. They move only a few millimetres, but they transfer all the load between your upper body and your legs. When one of these joints becomes irritated, or the ligaments and muscles around it are not controlling it well, you feel a deep ache or sharp pain just below the belt line, often to one side, sometimes spreading into the buttock, groin or upper thigh.

SI joint pain is thought to account for a meaningful share of what people call "lower back pain". It is especially common during pregnancy and in the months after childbirth, when hormones increase ligament laxity and the pelvis is under new loads. It also affects runners, people who have had a fall onto the buttocks, those with one leg slightly longer than the other, and anyone whose spine or hip stiffness forces the SI joint to work harder.

Most SI joint pain responds well to a combination of hands-on treatment and targeted strengthening of the muscles that stabilise the pelvis.

Causes and risk factors

• Pregnancy and the postnatal period
• A fall onto the buttocks or a heavy landing on one leg
• Repetitive one-legged loading such as running, football or kicking sports
• Leg-length difference or asymmetrical standing habits
• Stiffness in the lumbar spine or hips shifting load onto the SI joint
• Previous lumbar fusion surgery
• Inflammatory conditions affecting the spine (a GP may need to investigate these)

How we may be able to help

Diagnosis relies on a careful examination, because the SI joint does not show up well on standard imaging. We use a cluster of specific provocation tests, assess your pelvic alignment and movement, check your lumbar spine and hips to rule out other sources, and look at how you stand, walk and climb stairs.

Our physiotherapists use manual therapy to ease the irritated joint and surrounding muscles, then prescribe exercises that build control through the deep abdominal, gluteal and pelvic floor muscles. Where the joint is stiff or the pelvis is sitting asymmetrically, our chiropractor can use mobilisation or a controlled manipulation of the SI joint, which many people find gives a noticeable release.

Dry needling is useful for the tight gluteal and piriformis muscles that often guard an irritated SI joint. Interferential therapy may help settle pain in the early stage. A 3D posture scan can measure pelvic tilt and rotation to show asymmetry and track change over your course of care.

What you can do at home

• Avoid standing on one leg to dress — sit down to put on trousers, socks and shoes
• When turning in bed, keep your knees together and move as one unit
• Sit with your weight evenly on both sitting bones rather than crossing your legs
• Use ice for 10–15 minutes over the painful area after activities that flare it
• Practise gentle gluteal bridges and clam exercises as shown by your therapist
• If pregnant, a pelvic support belt may help during longer walks — ask us about fitting