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Sacroiliac (SI) Joint Pain Causes, Diagnosis, and Treatment Options

Sacroiliac (SI) joint pain can hurt in the hips, pelvis, and lower back, and cause numbness in your thighs.

A common cause of SI joint pain is pregnancy, which is also linked to pelvic pain. Both men and women can have SI joint pain, though it's sometimes attributed to something else.

The physiatrists at the Department of Physical Medicine and Rehabilitation (PM&R) are experts at diagnosing SI joint pain. We use physical therapy and other treatments to help people manage their pain and regain strength and mobility.

What Is Sacroiliac (SI) Joint Pain?

SI joint pain usually hurts in the lower back and butt. It can also hurt in the hip, groin, and thigh — often on just one side (though it can be both). Sometimes, SI joint pain can cause your leg to feel weak.

The sacroiliac (SI) joint lies next to the bottom of the spine and absorbs shock. It connects your spine to your hips. You can find your SI joint by feeling for the small dimple just below your waist and above your butt.

Your SI joint can hurt for many reasons. Some of those reasons may relate to the structure of your pelvis.

For example, if your pubic symphysis joint separates after you give birth to a child, it can affect your SI joint. (The pubic symphysis joint connects the two sides of your pelvis.)

SI joint pain is more common than most people know and causes between 15 to 30% of low back pain.

What causes SI joint pain?

There are many causes of SI joint flare ups. Some common causes include:

  • A change in your gait or joint motion. For example, knee pain or other types of pain can cause you to walk in a different way.
  • Trauma or injury to your lower back. This trauma can be major, such as a car crash, or minor, like improper lifting.
  • Pregnancy and childbirth (pregnancy causes the SI joint to loosen).
  • Cartilage wears down the joint (degenerative arthritis).

Contact the Department of Physical Medicine and Rehabilitation

Appointments and Referrals

Call 1-412-692-4400 or 1-800-533-8762 to make an appointment with, or refer people to, a doctor from the Department of Physical Medicine and Rehabilitation (PM&R).

What Are the Risk Factors and Complications of SI joint pain?

People of all ages, races, and genders can have SI joint pain.

For younger people, the most common cause is a sports injury or accident. For older people, decline with age causes SI joint pain.

For people designated female at birth, SI joint pain is more common during and after pregnancy.

Other risk factors include:

  • Having legs that are different lengths.
  • Being older.
  • Having inflammatory arthritis.
  • Having had spine surgery.

SI joint pain may go away on its own with rest. But it can also get worse and cause more pain. It can make it hard to do daily activities and exercises you love.

This is why it's good to see a doctor to learn the cause of your pain and how to treat it.

How Do I Prevent SI Joint Pain?

SI joint pain can be hard to prevent. It's often not a type of pain people think about until they have it.

Focusing on your posture while sitting may be one way to help prevent SI joint flare ups. Work to keep your weight even among both hips when you sit. Keeping your hips level, versus sitting with one higher than the other, can also help.

Regular exercise can also help prevent SI joint pain. If your joints are strong, you're less likely to injure them.

What Are the Symptoms of Sacroiliac Joint Pain?

Common symptoms of SI joint pain include:

  • A sharp pain in your lower back, just above your butt.
  • Dull pain when you stand up or move in a way that affects the area.
  • Pain that spreads to your butt, thighs, or groin.

SI joint pain can be hard to diagnose because it often mimics other health problems, including underlying causes of pelvic pain. But it's important to diagnose and treat SI joint pain. If not:

  • You could get the wrong diagnosis and have surgery you don't need.
  • Your symptoms could get worse and limit your range of motion and ability to sit or stand without pain.
  • You could end up with chronic pain.

How Do You Diagnose Sacroiliac Joint Pain?

To diagnose SI joint pain, your doctor will take a medical history and do a physical exam.

They'll likely move your leg, knee, and hip around while you lie on your back or your side on an exam table. Where you feel pain can help them diagnose or rule out the SI joint.

Your physiatrist may also order imaging studies, including:

  • X-rays of the low back, hips, or pelvis (to rule out a fracture).
  • CT scans, to get a more detailed look at the parts of your spine.
  • MRI, to see soft tissue and ligament or disc damage

They may also do tests to rule out gynecological issues, especially if your SI joint pain presents with pelvic pain. These tests include:

  • Pelvic ultrasound.
  • MRI of the pelvic area or low back.
  • Abdominal X-ray.

Treating Sacroiliac Joint Pain

Our physiatrists will work with you to manage your pain and rehab the SI joint.

Treatments may include:

  • Medicine: Drugs can treat both pain and inflammation. Some are over-the-counter medicines. Others may be prescription, such as muscle relaxers or drugs that help relieve nerve pain.
  • Physical therapy: Doing physical therapy can help you strengthen the muscles around the SI joint and make them more stable.
  • Wearing a brace: Depending on the cause of your SI joint pain, wearing a removable brace or belt can help.
  • Joint injections: Cortisone shots can reduce inflammation and relieve pain.
  • Pelvic floor therapy: Because SI joint pain and pelvic pain can exist together, pelvic floor therapy can help some people. It treats the pain through techniques such as deep tissue massage, and exercises to tighten and relax certain muscles.

SI joint pain is often related to pregnancy, which means you might need certain treatments. For more information about conditions related to pregnancy and postpartum care, visit UPMC Magee-Women's Hospital.

Make an Appointment

Call 1-800-533-8762 to make an appointment with a doctor from the Department of Physical Medicine and Rehabilitation.