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People may experience sacroiliac (SI) joint pain, also known as sacroiliitis, as a sharp or shooting pain in the lower back and buttocks. SI joint pain may or may not radiate down the legs.
In this article, we discuss the symptoms, risk factors, treatment, and complications of SI joint pain. We also cover types of exercises for SI joint pain and include tips for reducing this type of pain during pregnancy.
The symptoms of SI joint pain may vary from person to person, but they typically include:
- pain in the lower back, hips, or buttocks
- pain that radiates from the pelvis to the thighs, knees, or feet
- pain that worsens when standing up or sitting down
- numbness or tingling in the legs
- weakness in the legs
The SI joints are located in the space between the sacrum and the ilium. The sacrum is the large triangle shaped vertebrae at the base of the spine. The ilium is a pair of bones that sit one on each side of the sacrum, making up the outer part of the pelvis.
Muscle and ligaments in the hips hold the sacrum and ilium together, forming the SI joint. Hip exercises may help strengthen and stabilize the muscles that hold the SI joint together. Meanwhile, hip stretches can help relieve tension and pressure in this area.
People with SI joint pain may wish to consider incorporating the below exercises and stretches into their current treatment plan. However, as with any new form of treatment, it is best to consult a healthcare professional first.
The hip adductor muscles in the inner thighs help the body stay balanced and aligned. A person can strengthen these muscles by performing the following series of moves:
Step 1: Lie on the back and either rise onto the elbows or stay flat.
Step 2: Bend the knees and keep the feet flat on the floor.
Step 3: Place a pillow between the knees.
Step 4: Push the knees together to squeeze the pillow.
Step 5: Hold the position for 5–10 seconds and then relax.
People use the hip abductor muscles in the outer thighs to move the leg away from the body or rotate it from the hip joint. These muscles also help provide stability when a person stands on one leg or walks.
Step 1: Lie down on the back with both knees bent and a resistance band around the thighs just above the knees.
Step 2: Move the knees away from each other.
Step 3: Hold this position for 5–10 seconds.
Step 4: Release and return the knees to the starting position.
Hip flexor exercises can help keep the hips strong. A person can try the following exercise:
Step 1: Lie on the back and place several pillows under the lower legs. Rest the head on a pillow.
Step 2: Cross one leg over the other. Squeeze, hold for 5–10 seconds, and then relax.
Hip abductor stretch
The following stretch can help relieve tight hips:
Step 1: Lie on one side.
Step 2: Bend the top leg and rest it in front of the lower leg.
Step 3: Turn the upper body up to face the ceiling.
Step 4: Press the top leg into the floor.
This exercise stretches the lower back, hips, and buttocks:
Step 1: Lie down on the back with one leg straight and the other leg bent.
Step 2: Interlace the fingers of both hands just below the outside of the bent knee or behind the thigh.
Step 3: Gently pull the bent leg toward the chest.
Step 4: Hold for 5–10 seconds, then release the bent leg and repeat this stretch on the other leg.
The piriformis muscle sits deep in the buttocks. A person can stretch it by following the steps below.
Step 1: Lie down on the back with both knees bent and the feet on the floor, hip-width apart.
Step 2: Keeping the foot flexed, cross one leg over the other so that the ankle rests on the opposite knee.
Step 3: Grasp the back of the thigh of the supporting leg.
Step 4: Gently lift the supporting leg off the floor, keeping both knees bent and both feet flexed.
Step 5: Hold for 5–10 seconds, then release the stretch and repeat on the other leg.
A doctor can help a person narrow down which of the numerous available treatment options are best for addressing their specific symptoms.
Treatments for SI joint pain include self-care, medication, and surgery.
Low impact exercises and stretches, including those that feature in this article, can help strengthen the SI joint and relieve pressure in this area.
People who have SI joint pain may also benefit from physical therapy.
People can address SI joint pain at home by avoiding movements that exacerbate painful symptoms. Alternating between cold and hot compresses on the affected joint may help relieve pain.
People may also wish to consider wearing an elastic SI belt, which compresses the SI joint for additional lower back support.
SI joint pain that persists despite the use of exercises and other self-care remedies may require medication.
Drugs that may ease SI joint pain include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs, including ibuprofen and aspirin, can often help relieve mild-to-moderate pain.
- Muscle relaxants: Problems affecting the SI joint may cause painful muscle spasms. Muscle relaxants or prescription pain relievers can help alleviate severe SI joint pain.
- Joint injections: Doctors can inject corticosteroids in combination with local anesthetics directly into the SI joint, which may reduce inflammation and pain.
- Tumor necrosis factor (TNF) inhibitors: TNF inhibitors can help reduce inflammation due to axial spondyloarthritis, a progressive condition that can cause SI joint pain. According to a 2019 review of 19 research articles, TNF inhibitors effectively reduce inflammatory lesions in the SI joint for up to 4 years in people with early axial spondyloarthritis.
Surgery and other procedures
People who have SI joint pain that is severe or does not respond to medication may require medical intervention or surgery.
A doctor may recommend one of the following procedures, depending on the cause and severity of a person’s symptoms:
- Radiofrequency ablation: During this procedure, a doctor uses an electric current to heat a section of nerve tissue. This treatment interferes with the nerve’s ability to send pain signals to the brain.
- Peripheral nerve stimulation: This treatment involves the implantation of a small device into the sacrum. The device sends electrical impulses to the nerves passing through the sacrum to reduce SI joint pain.
- SI joint fusion: Doctors can treat severe cases of SI joint pain by surgically fusing the sacrum and ilium with metal plates or screws.
Experts consider SI joint pain to be one of the most common causes of lower back pain during pregnancy.
Changes in hormone levels may increase the risk of SI joint pain in some pregnant women. Relaxin, a hormone that the placenta and ovaries release, relaxes the ligaments surrounding the pelvis, making the SI joints less stable.
However, the exact role that relaxin plays in lower back pain during pregnancy remains up for debate. The authors of a 2012 review article concluded that there was a minimal association between relaxin levels and pregnancy-related pelvic pain.
Women who do experience lower back pain during pregnancy may benefit from the following treatments:
- exercises and stretches that strengthen the lower back and SI joints
- low dosages of aspirin or acetaminophen
- joint injections
- a pelvic girdle support belt or SI belt
However, anyone who is pregnant should talk to a doctor before trying any stretches or taking any medication.
There are many possible causes of SI joint pain, including injuries, inflammatory conditions, poor posture, and, in rare cases, infections.
Certain factors may increase a person’s likelihood of developing SI joint pain, such as:
Without treatment, SI joint pain may worsen over time. People may have reduced mobility and experience chronic lower back pain.
Chronic pain can affect aspects of a person’s daily life, including their mood, quality of sleep, and ability to perform physical tasks.
Other possible complications of untreated SI joint pain include reduced overall quality of life and symptoms of depression.
It may not always be possible to prevent SI joint pain, but people can reduce the risk by exercising and stretching regularly.
People can also avoid putting unnecessary pressure on their SI joints by maintaining a moderate body weight and adopting proper posture.
Immunomodulation may help prevent SI joint pain in people with autoimmune disease.
A doctor can diagnosis SI joint pain. Generally, they will begin by reviewing a person’s medical history and performing a physical exam.
If a doctor suspects that a problem with the SI joint is responsible for a person’s lower back pain, they will confirm their diagnosis with an SI joint block. An SI joint block is a minimally invasive procedure in which a doctor injects a local anesthetic into the SI joint.
If a person experiences pain relief shortly after their doctor administers the SI block, their SI joint is likely the source of their back pain.
In some cases, the doctor may also order blood tests to check for signs of infection or inflammation.
People with sacroiliac (SI) joint pain tend to experience a sharp or shooting pain in the lower back and buttocks.
It is often possible to ease SI joint pain at home with over-the-counter pain relievers, stretches, and exercises.
Doctors can treat moderate-to-severe SI joint pain with muscle relaxants and joint injections.
Surgery is a last resort treatment option for severe SI joint pain that does not respond to physical therapy or medication.