Sacroiliitis is the inflammation of one or both of the sacroiliac joints. These joints are in the lower back, where the spine meets the pelvis. It can lead to pain and stiffness in the lower back, legs, and hips.

Sacroiliitis is associated with many conditions that cause inflammation in the spine. It often occurs secondary to forms of arthritis.

This article looks at the causes and symptoms of and treatments for sacroiliitis.

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Sacroiliitis refers to inflammation in the sacroiliac joints, which link the ilium (the bone located on the top of each half of the pelvis) to the sacrum (the triangular bone situated between the two hipbones).

This inflammation may cause pain in the buttocks, lower back, and down a person’s legs.

Due to its often subtle symptoms, a healthcare professional may overlook sacroiliitis when diagnosing patients with lower back pain.

The main symptoms of sacroiliitis include:

  • pain in the buttocks and lower back
  • pain in the back of one or both legs
  • stiffness in the hips and lower back

Sometimes sacroiliitis can cause pain in the hips and feet, too, although this is less common. Sacroiliitis may also cause pain intermittently. People may experience more pronounced symptoms at night or upon waking.

There are a variety of treatments available for sacroiliitis. These include medications, exercises, and surgical procedures.


The following medications can help to treat sacroiliitis:

  • Pain relievers: Over-the-counter (OTC) pain medications may provide some relief. A doctor may prescribe stronger medicines if OTC options are not helping.
  • Muscle relaxants: Sacroiliitis can cause muscle spasms that may be painful. Muscle relaxants can help relieve these.
  • TNF inhibitors: This type of medication can help ease sacroiliitis if it is associated with autoimmune diseases such as ankylosing spondylitis. A 2016 study showed that TNF inhibitors could significantly improve both activity and joint function.

Home remedies and exercise

As well as prescribed medications, the following home remedies and exercises may help relieve sacroiliitis:

  • Rest: Avoiding the movements that aggravate sacroiliitis can help to reduce inflammation.
  • Ice and heat: Alternating placing ice and heat packs on the affected area may help relieve sacroiliitis.
  • Hip flexion exercises: This exercise involves lying on the back with the legs supported by a box or pillows. A person will then cross one leg over the other, squeeze the legs together, and then release.
  • Core strengthening: Exercises like crunches or holding a plank position can help stabilize the spine.

Surgery and other procedures

In severe cases where medication and exercise do not relieve sacroiliitis, a doctor may recommend one of the following surgeries or procedures:

  • Electrical stimulation: A medical professional may implant an electrical stimulator into the sacrum, which may help to reduce the pain.
  • Joint injections: Injected corticosteroids into the sacroiliac joint can help to reduce inflammation and pain. However, having too many injections in too short a time frame may cause other problems. As a result, doctors will limit the amount a patient can receive.
  • Radiofrequency denervation: This type of treatment works on the nerve tissue that may be causing sacroiliac pain.
  • Joint fusion: In severe cases, fusing the two bones with screws, a metal plate, or other fusion devices may help relieve sacroiliitis.
  • Bone graft: Another option involves placing a bone graft into the sacroiliac joint.

There are several potential causes of inflammation in the sacroiliac joints. These include:

  • Ankylosing spondylitis and reactive arthritis: These are progressive types of inflammatory arthritis that affect the spine and hips. Sacroiliitis is often an early sign. Not all people who experience sacroiliitis have these conditions.
  • Trauma: A sudden traumatic injury may damage the sacroiliac joints and cause inflammation, leading to degenerative sacroilitis.
  • Pregnancy: During pregnancy, the sacroiliac joints stretch to make room for the growing baby. This may put stress on the joints and cause sacroiliitis.
  • Infection: If the sacroiliac joint becomes infected, it becomes inflamed and prone to damage.

Reviews have also associated sacroiliitis with autoimmune or inflammatory conditions such as:

Physical actions may aggravate existing sacroiliitis, including sitting or standing for long periods, running, or placing too much weight on one leg for too long.

Sacroiliitis may be hard to diagnose as it can be mistaken for lower back pain caused by different conditions. As a result, a doctor may diagnose sacroiliitis through the exclusion of other conditions.

The doctor will begin the diagnosis with a pelvic x-ray. Thet may also perform several physical tests to assess if sacroiliitis is causing a person’s pain.

These can include applying pressure to the sacroiliac joints and making the patient move their hip joint through various ranges of motion.

A doctor may conduct further screening if unsure of the diagnosis. A 2018 review highlighted the importance of MRI tests as a diagnostic tool for sacroiliitis. However, the authors commented that without significant expertise, the chance of a false-positive diagnosis from MRI imaging is relatively high.

Computed tomography may sometimes be useful in diagnosing sacroiliitis.

Does sacroiliitis ever go away?

In most cases, sacroiliitis goes away with treatment within 2-4 weeks. However, research shows it can recur in as many as 30% of cases.

How serious is sacroiliitis?

Sacroiliitis is not life-threatening, but it can be debilitating. Long-term improvement will depend on the cause of the condition. For example, joint damage and degenerative forms of arthritis will need ongoing treatment to manage symptoms.

Sacroiliitis is a condition that results in one, or both, of the sacroiliac joints becoming inflamed. These joints are between the sacrum, a bony structure at the base of the spine, and the two uppermost hip bones.

Inflammation of the sacroiliac joints can lead to pain in the lower back, buttocks, and legs. It often occurs secondary to autoimmune conditions such as ankylosing spondylitis. Pregnancy, trauma, and infection may also cause sacroiliitis.

The condition shares symptoms with many mechanical lower back issues. A doctor will use physical tests and often MRI imaging to diagnose sacroiliitis.

There is a range of treatments available for sacroiliitis that can relieve the pain associated with the condition. A person with sacroiliitis may undertake courses of medication, physical therapy, and if other treatments do not relieve pain, surgery to treat the condition.

A doctor can recommend the best way to manage sacroiliitis symptoms and relieve pain associated with the condition.