Home Services & Fees First Visit Our Team Our Philosophy Blog Book Now

Conditions we treat

Sacroiliac Joint
Dysfunction

The SI joint is one of the most commonly missed drivers of lower back and sciatic-type pain. It sits at the junction between your spine and pelvis, and when it is not working properly, the effects travel far beyond it.

Book an Assessment

13-30%

of chronic low back pain originates from the SI joint

more risk of pelvic girdle pain with asymmetric SIJ laxity

91%

sensitivity using a 3-test provocation cluster

GOsC

Registered and fully insured practitioners

Understanding the condition

What is sacroiliac joint dysfunction?

Your sacroiliac joint sits where your sacrum, the triangular bone at the base of your spine, meets your pelvis on each side. You have one on the left and one on the right. Its job is not to move a great deal. It is to transfer load efficiently between your spine and your lower limbs every time you stand, walk, or move.

SIJ dysfunction means the joint is not doing that job properly. It might be moving too little. It might be moving asymmetrically. Or the muscles and ligaments around it may not be working together to keep it stable. Any of these states loads the joint abnormally, and the tissues around it, which are rich in nerve endings, respond with pain.

The important distinction is that SIJ dysfunction does not mean structural damage or inflammatory joint disease. It refers to suboptimal micro-movement within the joint's normal functional range. That is treatable. Thoroughly.

"Research using high-precision MRI in living patients confirms the SIJ does move. The question is never whether it moves. The question is whether it is moving well."

Common symptoms

Deep ache or sharp pain on one side of the lower back or buttock

Pain worse in the morning that eases with movement

Difficulty rolling over in bed or getting in and out of a car

Pain travelling into the back of the thigh or hip

Sciatic-type leg pain without disc or nerve root compression

Tenderness over the dimples in your lower back

A feeling of instability or giving way in the hip or lower back

Pain that worsens with prolonged sitting or standing on one leg

The sciatic connection

Why SI joint dysfunction causes leg pain

This is what most people find surprising. How can a joint in your pelvis cause pain down your leg? Three distinct mechanisms operate, and in many patients more than one is working at the same time.

Somatic referred pain via the sciatic nerve roots

The SIJ capsule and posterior ligaments are supplied by the same nerve roots, L4 to S3, that form the sciatic nerve. When the joint is irritated, pain travels along that same pathway into the buttock, back of the thigh, and sometimes as far as the calf. This is not radiculopathy. There is no nerve compression and no disc problem. The pain pattern mimics sciatica but arises from the joint. Getting the diagnosis right matters because the treatment is completely different.

Glute med inhibition and altered force closure

When the SIJ is not transferring load well, gluteus medius, the primary stabiliser of the pelvis during single leg stance, is frequently inhibited on the same or opposite side. This disrupts force closure of the joint and alters the mechanics of every step. The consequence is increased shear through the SIJ with every loading cycle, sustained nociceptive output from the posterior ligaments, and progressive compensatory tension through the hip and lumbar spine. Left unaddressed, the entire kinetic chain adapts around the dysfunction.

Piriformis as the bridge structure

Piriformis originates on the anterior sacrum and inserts on the greater trochanter, passing directly over the sciatic nerve. Altered sacral mechanics in SIJ dysfunction modifies piriformis resting length and tone. The sciatic nerve runs beneath piriformis in approximately 85% of people and through it in around 15%. A hypertonic piriformis in the context of SIJ dysfunction becomes a direct compressive or irritative structure on the nerve trunk, producing genuine neurogenic symptoms without any disc or foraminal pathology. This is why patients can have completely normal MRI findings and still have significant sciatic-type pain.

How we treat it

A whole-person approach to SI joint dysfunction

Treating the SIJ in isolation tends to produce short-lived results. The thoracolumbar junction, hip, and contralateral lower limb are almost always co-contributors and need to be addressed as part of the same clinical picture.

Our approach is staged by irritability. High-irritability presentations are treated gently first, working on surrounding soft tissue, breathing mechanics, and pelvic floor tone before progressing to direct joint work. As the joint settles, treatment builds to restore full load transfer and function.

High Irritability

Reduce afferent load first

Muscle energy technique, ligamentous tension balancing, diaphragm and pelvic floor normalisation. No provocation. Neural work deferred.

Moderate Irritability

Restore form and force closure

MET plus soft tissue to piriformis and gluteus medius. Assess contralateral hip. Begin ASLR-based activation. Neural mobilisation where indicated.

Low Irritability

Restore full function

HVLA where hypomobility confirmed. Progressive load transfer rehabilitation. Address L3/4 mobility and hip extension deficit. Neural work integrated throughout.

Whole kinetic chain

The hip, lumbar spine, and thoracolumbar junction are assessed in every SIJ presentation. Treating the joint without addressing these regions produces short-lived results.

Neural involvement screened

Every assessment includes a neural screen. If slump or SLR reproduces sciatic symptoms, management is adjusted even if the SIJ remains the primary driver.

No treatment blocks

We will give you an honest expectation after your first assessment. You will never be asked to commit to a package in advance.

No referral needed

You can book directly. Same-week appointments are usually available.

Common questions

Questions about SI joint dysfunction

My MRI came back normal. Could this still be SI joint dysfunction?

Yes, and this is extremely common. Standard MRI does not reliably detect SIJ dysfunction. The micro-movement changes and ligamentous irritation that drive the pain are below the threshold of most imaging. Normal MRI findings with ongoing sciatic-type pain are one of the clearest indicators that the SIJ should be assessed clinically.

How do you know it is the SI joint and not a disc?

Through clinical examination using a validated provocation cluster. Three or more positive tests from a validated set yields 91% sensitivity and 78% specificity against an injection-confirmed reference standard. This is clinically actionable diagnostic accuracy and does not require imaging.

Is this different to sciatica?

It can produce identical symptoms to sciatica but through a completely different mechanism. True sciatica involves compression of the sciatic nerve root, usually from a disc. SIJ-driven sciatic-type pain involves referred pain from the joint and piriformis irritation of the nerve trunk. The pain pattern can be indistinguishable, which is exactly why a thorough clinical assessment matters more than symptom location alone.

Can pregnancy cause SI joint problems?

Yes. During pregnancy, relaxin softens the pelvic ligaments in preparation for birth. Asymmetric SIJ laxity is associated with a threefold increase in pelvic girdle pain risk. Post-natal SIJ dysfunction is also extremely common and frequently goes undiagnosed.

How many sessions will I need?

This depends on how long the problem has been present and how the surrounding structures have adapted. Many patients notice significant improvement within two to four sessions. We will give you an honest assessment after your first appointment with no obligation to commit in advance.

Do I need a GP referral?

No. You can book directly. If we think your presentation warrants further medical investigation we will tell you clearly and can provide written clinical findings to support any onward referral.

David Feherty

Registered Osteopath & Principal

David has been in clinical practice since 1999 and sees a high volume of SIJ and sciatic-type presentations. He treats the full kinetic chain as a matter of course, the joint, the hip, the lumbar spine, and the neural system together.

BOst (Hons) GOsC Registered TPI Certified
Book with David →

Not sure if this is what you have?

That is exactly what the assessment is for. Book in and we will find out.

07946 356 373 · david@osteopathblackpool.co.uk

Book an Appointment What to Expect

As GOsC-registered osteopaths we are primary contact practitioners you do not need a GP referral and you can come directly to us. Where we identify symptoms that require medical investigation, we will tell you clearly and can provide written clinical findings to support any onward referral. If you are currently experiencing progressive neurological symptoms, bowel or bladder changes, or unexplained weight loss alongside back pain, please seek medical advice promptly alongside your osteopathic assessment. David Feherty is registered with the General Osteopathic Council (GOsC registration no. 1169).

Sacroiliac JointDysfunction