Sacroiliac joint pain is an under-recognised cause of buttock or groin pain. Generally, treatment consists of exercise therapy and activity modification. However, not all cases settle with simple treatments so injections are needed. When and how for SI joint injections?

What is the sacroiliac joint? 

sacroiliac joint pain

The sacroiliac joints are located between the sacrum (below the lumbar spine) and the pelvic bones. Essentially, they provide shock absorption and transfer load from the lower body to the upper body.

Causes of sacroiliac joint pain

Usually, repetitive trauma or force on the sacroiliac joint can come from activities such as running. However, other triggering factors include a direct fall onto the sacroiliac joint, an autoimmune disorder that attacks the sacroiliac joint (sacroiliitis), or pregnancy.

Diagnosis of sacroiliac joint pain

In general, the diagnosis of sacroiliac joint pain is tricky. Firstly, symptoms overlap other causes such as a herniated disc in the spine or hip arthritis. Moreover, special tests used for sacroiliac joint pain are not a slam-dunk for this condition. Finally, imaging is often normal despite true SI joint pain being present.

MRI is helpful to exclude a condition known as sacroiliitis, which is an immune system problem causing inflammation of the sacroiliac joint. Sometimes, an MRI can rule out pain from the lumbar spine (Sciatica) or pelvis (hamstring origin tendinopathy).

Somewhat controversially, a few experts think that an image-guided injection of the sacroiliac joint is the best test for SI joint pain. If a person experiences 75% decrease in pain after injection, then we can be more sure that the pain is from the joint.

Treatment including SI joint injection

glute bridges

Generally, we recommend simple treatments first. Physiotherapy consisting of strengthening, mobility exercises, and soft tissue therapy helps. Moreover, a brace to support the joint can be helpful particularly during pregnancy. Anti-inflammatory tablets such as ibuprofen can settle pain as well.

If sacroiliac joint pain persists, we consider a SI joint injection.

Rarely, do we ever consider surgery if at all.

More about SI joint injection

In general, we consider cortisone injections into the sacroiliac joint to treat inflammation and pain. The sacroiliac joint is deep and narrow meaning that we need imaging to get the cortisone into the right spot.

More recently, we have started to use platelet-rich plasma for select cases of sacroiliac joint pain. For example, people with hypermobility or a history of trauma can suffer from sacroiliac joint dysfunction and may benefit from 1-2 PRP injections to aid in the healing of ligaments and the joint.

Traditionally, we use expensive X-rays with a dye for a SI joint injection.  However, more recently, many doctors are using ultrasound. There are many advantages to using ultrasound including a lack of radiation and less cost. Moreover, recent studies suggest that the accuracy is similar whether you use an X-ray or ultrasound.

Sometimes, a SI joint injection is combined with a piriformis injection especially when signs are mixed.

Final word from Sportdoctorlondon

Sacroiliac joint pain is a common and under-reported cause of buttock pain. In general, you should see a doctor who can diagnose and manage SI joint pain. Ultrasound-guided SI joint injections are just as good as traditional X-ray-guided injections (but at least half the price). Sometimes, SI joint injections are combined with piriformis injection to get better results.

Related conditions:

Dr. Masci is a specialist sport doctor in London. 

He specialises in muscle, tendon and joint injuries.

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