Your sacroiliac (SI) joint is the lowest part of your back and is often the cause of lower back pain. Treating SI joint pain often involves a combination of therapies such as physical therapy and medications.

Your sacroiliac (SI) joint is located in your lower back where your spine meets your pelvis. It’s the cause of up to 25% of cases of lower back pain.

Pain in your SI joint can be sharp or dull depending on the underlying cause. Some common causes of SI joint pain include:

  • sudden injury
  • pregnancy
  • arthritis

SI joint pain often resolves with conservative treatment like physical therapy, rest, or medications. Your doctor may recommend injections, radiofrequency ablation, or surgery if other options don’t give you relief.

Read on to learn more about the treatment options for SI joint pain.

Doctors generally recommend conservative treatment options for SI joint pain before opting for more invasive treatments. A combination of treatments may help you manage your symptoms and promote healing.

Treatment options include:

Resting during the acute phase of your injury (about 1 to 3 days) may help promote healing in the joint. Extended periods of inactivity, however, aren’t recommended, as resting for too long can contribute to increased stiffness.

Activities that may aggravate your SI joint include running and any activity where you have to twist your body.

If possible, try to do gentle exercises, like walking and SI joint stretches. These activities can help keep blood flowing to the muscles in your lower back, which may help promote healing and prevent stiffness.

Medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) may help you manage pain and inflammation in the 2 weeks following an SI joint injury. Medications can be combined with other treatments like rest and ice to help reduce inflammation.

Muscle relaxants may also help reduce pain in the initial stages of a SI injury by relaxing the muscles around your joint.

A type of drug called anti-tumor necrosis factor may be recommended for treating inflammation in your SI joint if the pain is caused by an autoimmune disease called ankylosing spondylitis.

Applying ice to your lower back can help reduce inflammation in the early stages after injury. Ice can be combined with rest and medications.

Heat may help reduce stiffness in the later stages of your injury. But it’s generally recommended that you avoid applying heat to your lower back during the acute phase of your injury, which lasts up to about 3 days.

Learn more about treating injuries with heat and cold.

Physical therapy can be started as early as 1 to 3 days after your injury. A physical therapist can help treat underlying problems that led to your injury and restore motion through your joint. They can also give you a custom home exercise and stretching program to prevent injury reoccurrence.

Your physical therapy plan will likely focus on strengthening weak muscles that put extra stress on your SI joint. Muscles that are often weak in people with SI joint injuries include:

Your physical therapist may also perform certain manipulations to help relieve tight muscles around your lower back. Generally, at least five sessions are needed to decrease pain and improve function.

If conservative options aren’t effective, your doctor may recommend SI joint injections. These injections contain a mixture of corticosteroids to reduce inflammation and anesthesia to block pain.

Success rates as high as 90% have been reported. However, pain relief is temporary, and injections need to be repeated three to four times per year for continuous relief.

Doctors also sometimes perform injections as part of the diagnostic process to confirm that your pain is coming from your SI joint. If you have at least 75% pain relief from an SI injection, it could be an indication that your SI joint is the source of your pain.

Read more about the success rates of SI joint injections.

Radiofrequency ablation uses radio waves to destroy nerves that carry pain signals from your SI joint to your brain. Your doctor may recommend radiofrequency ablation if injections and more conservative options aren’t effective.

In a 2022 review, researchers found evidence that radiofrequency ablation can have benefits for chronic SI joint pain for up to 12 months, but there’s still a lack of research looking at its effectiveness for more than 12 months.

A type of surgery called spinal fusion is the last resort for SI joint pain that doesn’t respond to more conservative treatments. This procedure involves permanently fusing together your spine and pelvis. It may reduce your pain, but it also limits motion through the joint, which may cause other back problems in the future.

In a small study from 2018, researchers found an average of 73% reduction in lower back pain in 19 participants 1 year after undergoing SI joint fusion.

SI joint pain often goes away without complications when it’s caused by minor injuries or pregnancy. Pregnancy-related SI pain usually goes away within 12 months of giving birth.

Some types of arthritis that can affect the SI joint such as ankylosing spondylitis can cause long-term pain. Taking medications such as anti-tumor necrosis factor as prescribed may help minimize pain and inflammation.

SI joint pain is very common. Most people can successfully manage their pain with conservative options like physical therapy, medications, and rest.

If these treatments aren’t effective, your doctor may recommend injections or a technique called radiofrequency ablation. The last resort is a type of surgery called spinal fusion. Spinal fusion involves permanently joining together your pelvis and spine.