Sacroiliac joint pain usually comes from a combination of trauma, aging, and everyday wear and tear. The sacroiliac joint connects your lower spine to your pelvis, and when it moves too much or too little, pain follows. Research published in the International Journal of Spine Surgery identifies pregnancy, falls, repetitive strain, and arthritis as the most common triggers. For most people, the pain starts in the lower back and radiates into the buttock, hip, or groin. It is rarely one single cause — it is usually a mix of factors that build up over time.
What Is the Sacroiliac Joint and Why Does It Hurt?
The sacroiliac joint sits between your sacrum — the triangular bone at the base of your spine — and your ilium, which is part of your pelvis. You have two of them, one on each side. These joints are designed for stability, not a wide range of motion. Their job is to transfer weight from your upper body to your legs when you stand and walk.
Pain happens when the joint becomes irritated. This can happen because the joint moves too much, a condition called hypermobility. Or it can happen because the joint stiffens and locks up, called hypomobility. Both situations stress the surrounding ligaments, muscles, and nerves. The result is a dull ache or sharp pain that can be hard to pinpoint.
According to the American Academy of Orthopaedic Surgeons, sacroiliac joint dysfunction accounts for 15 to 30 percent of all chronic low back pain cases. Many people go months or years without a correct diagnosis because the symptoms mimic disc problems or sciatica.
How Trauma Triggers Sacroiliac Pain
Physical injury is one of the most direct causes of sacroiliac pain. A fall onto the buttocks, a car accident, or a sudden twisting motion can stretch or tear the ligaments that hold the joint in place. Once those ligaments are damaged, the joint becomes unstable.
Research from the Journal of Orthopaedic & Sports Physical Therapy found that people with a history of falls or motor vehicle accidents are significantly more likely to develop sacroiliac pain later. The injury does not have to be recent. Many patients report a fall that happened years earlier. The joint may have compensated for the damage for a long time before symptoms finally appeared.
Repetitive trauma also counts. Runners, weightlifters, and people who do heavy manual labor put repeated stress on the sacroiliac joint. Over time, that stress can lead to inflammation and pain. It is not about one bad day — it is about thousands of small impacts that add up.
Does Aging Cause Sacroiliac Joint Problems?
Yes, aging is a major factor. As you get older, the cartilage in your sacroiliac joints wears down. The ligaments that stabilize the joint lose some of their elasticity and strength. The joint itself can develop bone spurs or degenerative changes that limit normal movement.
Osteoarthritis is common in the sacroiliac joint after age 50. The Arthritis Foundation reports that sacroiliac joint arthritis is often underdiagnosed because it presents as general low back pain. Unlike hip arthritis, which typically causes groin pain, sacroiliac arthritis tends to cause pain directly over the joint, about an inch to the side of your spine.
Another aging-related condition is ankylosing spondylitis, a type of inflammatory arthritis that targets the sacroiliac joints first. This condition usually starts in younger adults, but its effects worsen with age. The Cleveland Clinic notes that sacroiliitis — inflammation of the sacroiliac joint — is one of the earliest signs of this disease.
What Causes Sacroiliac Pain: Trauma, Aging, and More — Pregnancy and Childbirth
Pregnancy is one of the most common causes of sacroiliac pain in women. During pregnancy, the body releases a hormone called relaxin. Relaxin loosens the ligaments throughout the pelvis to prepare for childbirth. The sacroiliac ligaments become more flexible, which can lead to instability and pain.
A study in the European Spine Journal found that up to 50 percent of pregnant women experience some form of pelvic girdle pain, with the sacroiliac joint being a primary source. The pain often starts in the second trimester and can persist for months after delivery. For some women, the ligaments never fully tighten back to their pre-pregnancy state, leaving them with chronic instability.
Childbirth itself can also cause trauma to the joint. A difficult delivery, especially one involving forceps or vacuum extraction, can stretch or tear the sacroiliac ligaments. This is not widely discussed, but it is well documented in obstetric physical therapy literature.
Other Common Causes: Arthritis, Infection, and Surgery
Arthritis is not limited to aging. Certain forms of arthritis, such as psoriatic arthritis and reactive arthritis, can inflame the sacroiliac joint at any age. Gout can also affect the joint, though this is rare. The common thread is inflammation within the joint space itself.
Infection of the sacroiliac joint, called septic arthritis, is uncommon but serious. It causes severe pain, fever, and difficulty bearing weight. According to the Journal of Bone and Joint Surgery, septic sacroiliitis requires immediate antibiotic treatment and sometimes surgical drainage. If you have sudden, severe sacroiliac pain with a fever, seek medical attention right away.
Spinal fusion surgery is another cause. When the lower spine is fused, the sacroiliac joint takes on more load than it was designed to handle. Research in Neurosurgery found that up to 40 percent of patients who have lumbar fusion develop sacroiliac pain within two years. The joint simply cannot handle the extra stress.
What Does the Research Say About Diagnosis and Treatment?
Diagnosing sacroiliac pain is not straightforward. There is no single test that confirms it with certainty. Doctors usually rely on a combination of physical exams, imaging, and diagnostic injections. The most reliable method is a fluoroscopically guided injection of numbing medication into the joint. If the pain goes away after the injection, the sacroiliac joint is likely the source.
X-rays and MRI scans can show arthritis, fractures, or infection, but they cannot diagnose ligament laxity or joint dysfunction. A 2020 review in Pain Medicine concluded that imaging alone is insufficient for diagnosis. The review emphasized that clinical history and physical exam findings are just as important as any scan.
Treatment usually starts with physical therapy. The goal is to strengthen the muscles around the joint to provide stability. This includes the glutes, core, and lower back muscles. Manual therapy, such as joint mobilization, can also help if the joint is too stiff or too loose.
| Treatment | What It Does | Evidence Level |
|---|---|---|
| Physical therapy | Strengthens stabilizing muscles | Strong — multiple studies support it |
| Chiropractic manipulation | Adjusts joint alignment | Moderate — helpful for some, not all |
| SI joint belt | Provides external compression | Weak — mostly patient-reported relief |
| Corticosteroid injection | Reduces inflammation | Strong for short-term relief |
| Radiofrequency ablation | Blocks pain signals from joint nerves | Moderate — works for some, not permanent |
| Surgery (fusion) | Fuses the joint to stop movement | Weak — reserved for severe, unresponsive cases |
What to Avoid If You Have Sacroiliac Pain
Avoid movements that put uneven stress on the joint. This includes twisting while lifting, standing on one leg for long periods, and running on hard surfaces. Sleeping on your stomach can also aggravate the joint because it forces the lower back into extension.
Some people report relief from chiropractic adjustments, but evidence is mixed. A 2019 study in Spine found that manipulation helped some patients but made others worse, especially those with hypermobility. If your joint is already too loose, forceful adjustments can cause more instability.
- Avoid high-impact activities like running and jumping until symptoms improve
- Avoid sitting on uneven surfaces or with your wallet in your back pocket
- Avoid sleeping on your stomach — try side sleeping with a pillow between your knees
- Avoid long periods of standing in one place without shifting weight
- Avoid heavy lifting without engaging your core and glutes
One non-obvious point: sitting on a soft couch or deep chair can make sacroiliac pain worse. The soft surface allows your pelvis to tilt unevenly, which stresses the joint. A firm chair with good lumbar support is usually better.
Common Misconceptions About Sacroiliac Pain
The biggest misconception is that sacroiliac pain is the same as sciatica. They can feel similar, but they are not the same. Sciatica comes from compression of the sciatic nerve in the lower spine. Sacroiliac pain comes from the joint itself. The pain can radiate down the leg, but it does not usually go below the knee. True sciatica often goes all the way to the foot.
Another myth is that you can “pop” the sacroiliac joint back into place like a chiropractor would. The joint does not actually dislocate. It becomes irritated or unstable. There is no bone out of place to fix. Treatment is about restoring normal movement and strength, not alignment.
Some people believe that rest is the best treatment. Complete rest usually makes sacroiliac pain worse. The muscles around the joint weaken, which leads to more instability. Gentle movement and targeted strengthening are more effective than bed rest.
Frequently Asked Questions
Can sacroiliac pain go away on its own?
Mild cases sometimes resolve with rest and activity modification. Chronic cases usually require physical therapy or other treatment to address the underlying cause.
What is the fastest way to relieve sacroiliac pain?
Ice or heat applied directly over the joint for 15 minutes can reduce acute pain. A sacroiliac belt may also provide immediate relief by stabilizing the joint.
Is walking good for sacroiliac joint pain?
Walking on flat, even ground is generally safe and can help maintain muscle strength. Avoid uneven terrain or long strides that stress the joint.
What kind of doctor treats sacroiliac pain?
A physiatrist, orthopedic surgeon, or physical therapist with experience in sacroiliac dysfunction is a good starting point. A pain management specialist can perform diagnostic injections.
