Sacroiliitis, or inflammation of the sacroiliac (SI) joint where your spine meets your pelvis, is treated with a combination of anti-inflammatory medication, targeted exercise, and in stubborn cases, procedures like joint injections or radiofrequency ablation. Most people improve with conservative measures over several weeks, but the right approach depends on whether your pain is from an injury, mechanical stress, or an underlying inflammatory condition like ankylosing spondylitis.
What Causes SI Joint Pain
Your two sacroiliac joints sit at the base of your spine and absorb shock between your upper body and legs. They can become inflamed from pregnancy, repetitive stress, trauma, arthritis, or infection. But one of the most important distinctions is whether the inflammation is mechanical (caused by abnormal movement or injury) or part of a systemic inflammatory disease.
Sacroiliitis is a hallmark feature of axial spondyloarthritis, a family of conditions that includes ankylosing spondylitis. In these diseases, the immune system drives chronic inflammation in the spine and SI joints, and the condition can also cause eye inflammation, inflammatory bowel disease, and psoriasis. If your SI joint pain started gradually before age 45, improves with movement but worsens with rest, and comes with prolonged morning stiffness, your doctor will likely investigate an inflammatory cause. This matters because mechanical and inflammatory sacroiliitis are managed differently, especially when it comes to advanced medications.
First-Line Treatment: NSAIDs
Nonsteroidal anti-inflammatory drugs are the starting point for nearly all sacroiliitis treatment. Over-the-counter options like ibuprofen and naproxen reduce both pain and inflammation. For inflammatory sacroiliitis linked to spondyloarthritis, NSAIDs are particularly effective and sometimes require higher doses to maintain symptom control. If one NSAID doesn’t work well, switching to a different one is standard practice since people respond differently to each drug.
When NSAIDs alone aren’t enough or cause side effects like stomach irritation, doctors may add other medications. For sacroiliitis driven by an autoimmune condition, current guidelines recommend trying at least two different NSAIDs before moving to stronger options. That progression typically leads to biologic medications, which target specific parts of the immune system responsible for inflammation.
Biologic and Advanced Medications
For people with inflammatory sacroiliitis who don’t respond adequately to NSAIDs, biologic drugs that block tumor necrosis factor (TNF) or interleukin-17 are the next step. These are injectable or infusion-based medications that suppress the specific immune pathways driving joint inflammation. A newer class of oral medications called JAK inhibitors works through a different mechanism but targets similar inflammatory signals.
Eligibility for these treatments typically requires an elevated inflammatory marker on blood work, signs of inflammation visible on MRI of the SI joints, or evidence of structural damage on X-ray. Patients with elevated inflammatory markers tend to have the strongest response to biologics. Older disease-modifying drugs like methotrexate, commonly used for rheumatoid arthritis, play a limited role in SI joint inflammation specifically, though they may be prescribed in smaller doses when peripheral joints are also involved.
Exercises That Stabilize the SI Joint
Physical therapy focused on core stabilization and hip flexibility is one of the most effective long-term strategies for sacroiliitis. The goal is to strengthen the muscles that support your pelvis so the SI joint bears less stress. Several specific exercises form the foundation of most PT programs:
- Bridges: Lying on your back with knees bent at about 90 degrees, tighten your abdominal muscles, then squeeze your glutes and lift your hips until your shoulders, hips, and knees form a straight line. Hold for about 6 seconds and lower slowly.
- Single knee-to-chest stretch: Lying on your back, clasp your hands under one knee and pull it toward your chest while keeping your other foot flat on the floor and your lower back pressed down. Hold 15 to 30 seconds, repeat 2 to 4 times per leg.
- Clamshells: Lying on your side with knees bent and feet together, raise your top knee without letting your hips roll backward. Hold for 6 seconds, repeat 8 to 12 times per side.
- Core arm raises: On hands and knees, tighten your core and raise one arm straight out in front of you without letting your shoulder drop. Hold for 6 seconds, working up to 10 to 30 seconds over time. Repeat 8 to 12 times per arm.
- Bird-dog leg raises: From the same hands-and-knees position, extend one leg straight behind you while keeping your hips level. As this gets easier, raise the opposite arm at the same time.
Consistency matters more than intensity. These exercises should not increase your pain. If they do, back off and work with a physical therapist to modify them. Most people begin noticing improvement within a few weeks of regular exercise, though building lasting stability takes longer.
Ice, Heat, and Early Pain Management
In the first 48 to 72 hours after a flare-up, ice is your best option. Apply it for 10 to 15 minutes at a time with a towel between the ice and your skin, then let the area return to normal temperature before reapplying. Repeat throughout the day as needed. After those first few days, switching to heat or alternating between heat and ice often provides more relief. Heat sessions should also last 10 to 15 minutes with a protective barrier, and you should avoid falling asleep with a heating pad on.
Doctors generally recommend returning to your usual activities within 24 to 48 hours when possible, since prolonged rest tends to increase stiffness and delay recovery. If there’s a muscle spasm component to your pain, a short course of muscle relaxants during those first few days can help.
Joint Injections
When oral medications and physical therapy aren’t providing enough relief, corticosteroid injections directly into the SI joint can reduce inflammation for weeks to months. These are performed under imaging guidance (usually fluoroscopy or ultrasound) to ensure accurate placement. The injection combines a corticosteroid with a local anesthetic, so you may feel some immediate relief from the numbing agent, followed by longer-term improvement as the steroid takes effect over several days.
SI joint injections also serve a diagnostic purpose. If an injection into the joint significantly reduces your pain, it confirms the SI joint as the source, which is useful because SI joint pain can mimic other conditions like herniated discs or hip problems. Diagnosing SI joint pain in the first place often requires at least three positive results on a set of physical provocation tests that stress the joint in different directions.
Radiofrequency Ablation for Chronic Pain
For people with confirmed SI joint pain that keeps returning despite injections and therapy, radiofrequency ablation offers longer-lasting relief. This procedure uses heat generated by radio waves to interrupt the nerve signals carrying pain from the SI joint to the brain. A newer version called cooled radiofrequency ablation has shown particularly strong results.
In a multicenter study comparing cooled radiofrequency ablation to standard medical management (which included steroid injections, nerve blocks, physical therapy, and acupuncture), patients who received the ablation had significantly better outcomes at three months. Over half of the ablation group experienced at least 30% pain relief, compared to just 4% in the standard management group. About 42% achieved a 50% or greater reduction in pain scores. The pain relief from ablation typically lasts 6 to 12 months or longer before the nerves regenerate, at which point the procedure can be repeated.
SI Joint Fusion Surgery
Surgery is reserved for people who have exhausted all nonsurgical options and still have pain that limits daily life. SI joint fusion uses small implants to stabilize the joint and eliminate the painful motion. Before recommending it, your surgeon will review everything you’ve already tried, including medications, physical therapy, injections, and possibly ablation, and how well each worked.
Modern SI joint fusion is a minimally invasive procedure, usually performed through a small incision. Recovery involves several weeks of limited weight-bearing and gradual return to activity. It’s not appropriate for everyone, and outcomes are best when the SI joint has been clearly confirmed as the primary pain source through diagnostic injections and imaging.
Treating the Underlying Condition
If your sacroiliitis is part of a broader inflammatory condition like ankylosing spondylitis, treating the SI joint alone won’t be enough. Long-term management focuses on controlling systemic inflammation to prevent joint damage throughout the spine. This means ongoing use of NSAIDs or biologic medications, regular exercise (swimming and walking are especially well-suited), and monitoring for complications in other parts of the body like the eyes and gut.
People with inflammatory sacroiliitis benefit from staying physically active even when symptoms are mild. Unlike mechanical injuries where rest plays a bigger role, inflammatory SI joint disease tends to worsen with inactivity. A combination of cardiovascular exercise, stretching, and the core stabilization exercises described above forms the long-term management strategy that keeps most people functioning well.