SI Joint Pain: Symptoms, Causes, and When to See a Pain Specialist

If you've been dealing with stubborn low back pain that doesn't seem to respond to the usual treatments, there's a good chance your sacroiliac joint — or SI joint — could be the culprit. In my practice, SI joint dysfunction is one of the most commonly overlooked causes of lower back and buttock pain. Many patients come to me after months (sometimes years) of being told their MRI looks fine, yet they're still hurting.

Let's talk about what the SI joint actually is, how to recognize the symptoms, and what you can do about it.

What Is the SI Joint?

The sacroiliac joint connects your sacrum (the triangular bone at the base of your spine) to your ilium (the large pelvic bone on each side). You have two SI joints — one on each side. These joints don't move much, but they play a critical role in transferring the weight of your upper body to your legs when you stand, walk, or climb stairs.

Think of the SI joints as the hinges between your spine and your pelvis. When they're working properly, you never think about them. When they're irritated or inflamed, they can make everyday activities miserable.

Common SI Joint Pain Symptoms

SI joint pain can mimic other conditions, which is why it's so frequently misdiagnosed. Here's what to watch for:

• Low back pain on one side — This is the hallmark symptom. The pain is usually felt below the belt line, off to one side rather than in the center of the spine.
• Buttock pain — Many patients describe a deep ache in one buttock that can feel like a constant bruise.
• Hip pain — SI joint pain often radiates into the hip, making it easy to confuse with hip arthritis or bursitis.
• Groin pain — Less common, but some patients feel discomfort in the groin area.
• Pain that worsens with sitting or standing for long periods — If you notice the pain gets worse when you sit for a long car ride or stand in one position too long, that's a red flag for the SI joint.
• Pain when climbing stairs or getting out of a car — These movements put direct stress on the SI joint.
• Stiffness in the lower back and hips, especially in the morning.

The pain can occasionally radiate down the back of the thigh, which is why SI joint dysfunction is sometimes confused with sciatica. However, true SI joint pain rarely travels below the knee.

What Causes SI Joint Pain?

Arthritis

Osteoarthritis can wear down the cartilage in the SI joint over time, just like it does in the knee or hip. This is one of the most common causes I see in patients over 50.

Injury or Trauma

A fall, car accident, or any impact to the pelvis can damage or inflame the SI joint. Even a single awkward step off a curb can trigger it.

Pregnancy

During pregnancy, the body releases hormones that loosen ligaments to prepare for childbirth. This can make the SI joints hypermobile and painful. Many women develop SI joint pain during or after pregnancy that persists for months.

Hypermobility

Some people naturally have more flexible joints. While this might seem like an advantage, excessive movement in the SI joint can lead to instability and chronic pain.

Uneven Stress on the Pelvis

Leg length discrepancy, scoliosis, or even habitually carrying a heavy bag on one side can place unequal stress on the SI joints over time.

Prior Spinal Surgery

Patients who've had lumbar fusion surgery sometimes develop SI joint problems afterward. When the spine is fused, the SI joint has to absorb more force than it was designed to handle.

How Is SI Joint Pain Diagnosed?

Physical Examination

A pain specialist will perform specific provocation tests — maneuvers designed to stress the SI joint and reproduce your pain. These include tests like the FABER test, compression test, and thigh thrust. When three or more of these tests are positive, there's a strong likelihood that the SI joint is the source of your pain.

Imaging

X-rays and MRI scans can sometimes show signs of arthritis or inflammation in the SI joint, but here's the thing — imaging alone isn't enough to diagnose SI joint dysfunction. Many people have normal-looking imaging but still have significant SI joint pain.

Diagnostic Injection

The gold standard for confirming SI joint pain is a diagnostic injection. Under fluoroscopic (X-ray) guidance, a small amount of local anesthetic is injected directly into the joint. If your pain improves significantly afterward, that confirms the SI joint as the pain source. In my practice, I consider this step essential before recommending any advanced treatment.

Treatment Options for SI Joint Pain

The good news is that SI joint pain responds well to treatment, especially when caught early.

Conservative Treatments

• Physical therapy — Targeted exercises to strengthen the muscles around the pelvis and improve stability. This is almost always my first recommendation.
• Anti-inflammatory medications — NSAIDs like ibuprofen can help manage flare-ups.
• SI joint belts — A supportive belt worn around the pelvis can provide stability and reduce pain.
• Activity modification — Avoiding prolonged sitting, using proper body mechanics, and adjusting your workstation.

Interventional Treatments

• SI joint injections — A corticosteroid injection into the joint can reduce inflammation and provide weeks to months of relief.
• Radiofrequency ablation (RFA) — For patients who respond to injections but need longer-lasting relief, RFA uses heat to disrupt the nerves that carry pain signals. Results can last 6 to 18 months.
• SI joint fusion — In cases where conservative and interventional treatments haven't provided adequate relief, a minimally invasive fusion procedure can stabilize the joint permanently.

When Should You See a Pain Specialist?

I recommend seeing a pain specialist if:

• Your low back or buttock pain has lasted more than 4 to 6 weeks despite rest and over-the-counter medications
• The pain is affecting your ability to work, sleep, or enjoy daily activities
• You've been told your spine MRI is “normal” but you're still in pain
• You've tried physical therapy without meaningful improvement
• Your pain worsens with sitting, standing, or transitional movements like getting out of bed

SI joint dysfunction is treatable — but it starts with an accurate diagnosis. Too many patients suffer unnecessarily because the SI joint simply wasn't considered. If any of this sounds familiar, it might be time to have a conversation with a pain specialist who can evaluate your SI joints directly.

Written by Dr. Varun Patibanda, M.D., D.A.B.P.M.