Sacroiliac Joint Pain

The sacro-iliac joints sit in the pelvis. There is one either side and sits in the buttock area. The ligaments around the sacro-iliac joint are extremely strong and cover the joint in the front and back. Load is transferred from the leg through the sacro-iliac joint to the spine each time we step during our walking pattern.
Pain originating in the sacro-iliac joint is commonly felt in the back, buttock as well as into the thigh. Pain can arise from either injury to the ligaments around the joint, which can lead to excessive movement. The joint can also undergo degenerative change and cause pain. The joint can also be painful in pregnancy as well as in some inflammatory conditions including ankylosing spondylitis.
The pain tends to be one sided and can give symptoms very similar to sciatica but more frequently, pain only refers into the buttock and thigh.
Common causes of sacro-iliac joint symptoms are from a traumatic event, prior lumbar fusion with regards to increasing biomechanical stresses, during pregnancy and childbirth, inflammatory conditions as well as degenerative changes.
After taking a history and examination, specific tests can be done to localise the pain to the sacro-iliac joint. To assist in diagnosis, x-rays, CT or MRI scan can be done to clarify whether it is the sacro-iliac joint or an adjacent lumbar disc that may be causing the symptoms.
An injection into the joint can be used as a diagnostic and therapeutic test and if this does alleviate the pain, then this has clarified the origin.
The injections are done using x-ray guidance and the response can last for hours, days or weeks and should be associated with physical therapy that if long lasting pain relief is not achieved with injections then an SI joint fusion may be suggested as a minimally invasive treatment.