Published Date: Dec 2023


What is Sacroiliac Joint Fusion?

The sacroiliac joint, commonly referred to as the SI joint, connects the sacrum to the ilium of the pelvis on both sides of the body. This joint helps transfer weight from the torso down through the legs. Sacroiliac joint fusion (SIJF) is a surgical procedure that joins or fuses the sacrum and ilium together to eliminate motion and relieve pain caused by injury or deterioration of the sacroiliac joint.

Causes of Sacroiliac Joint Pain

There are several factors that can cause sacroiliac joint pain:

Injury or Trauma

Direct injury or trauma to the pelvis area from a car accident, fall, or sports injury can damage the sacroiliac joint. Over time, this damage can lead to instability, arthritis, and pain.

Degenerative Changes

The natural process of aging and wear-and-tear can cause the cartilage within the joint to deteriorate. As the cartilage breaks down, it leads to inflammation, stiffness, and pain in and around the SI joint.

Inflammatory Arthritis

Conditions like ankylosing spondylitis or reactive arthritis that cause inflammation in the joints can also affect the sacroiliac joints. Over time, this chronic inflammation can degrade the joints.


Anatomical issues like leg length discrepancy or changes in gait from previous injury can put abnormal stress on the SI joint over the years and lead to injury or strain.

Sacroiliac Joint Fusion Surgery

When more conservative treatment options like pain medication, injections, or physical therapy fail to provide relief, sacroiliac joint fusion may be recommended. The goal of SIJF surgery is to eliminate motion at the joint that is causing pain.

 There are a few common techniques used for sacroiliac joint fusion:

- Minimally Invasive Surgery: This approach uses small incisions and specialized implants inserted through the skin to fuse the joints. Recovery is often quicker with less post-operative pain.

- Open Surgery: The traditional open approach requires a larger incision to access the joint. Bone grafts are placed between the sacrum and ilium which are then held together with plates, screws or other fixation devices.

- Lateral Transfixation: This technique places screws through the ilium above and below the joint to effectively lock it in place without disrupting the joint space.

- Hip Pinning/Iliosacral Screws: Long screws are inserted from the back of the ilium bone to the sacrum on each side through small incisions.

The specifics depend on each individual case but the goal is to eliminate all joint motion and promote bone fusion.

Rehabilitation after Surgery

Post-operative recovery usually takes 4-6 months. Patients begin light physical therapy soon after surgery to increase range of motion and strength without aggravating the healing fusion site. Weight-bearing activities are limited at first and progressed slowly. Most people can resume daily activities within 6-8 weeks but further recovery may continue for up to a year as the bone fuses completely.

Results and Risks of Sacroiliac Joint Fusion

- Studies report success rates of 75-90% pain relief after SIJF surgery for properly selected candidates. However, it may take up to a year to fully gauge results.

- Potential risks include infection, nerve injury, blood clots, implant failure or non-union of the bone. Re-operation may occasionally be needed.

- As with any spine surgery, risks increase with factors like age, obesity, smoking, and certain pre-existing conditions.

- Fusion eliminates motion at the SI joint but adjacent levels may experience more stress over time which could lead to new problems.

- Not all patients respond equally. Some gain complete relief while others have residual or intermittent pain that requires management.

- For optimal outcomes, close compliance with post-op precautions and physical therapy is strongly advised.


In summary, sacroiliac joint fusion is a treatment option for persistent and debilitating pain caused by injury or degeneration at the sacroiliac joint when conservative options fail to provide sufficient relief. By fusing the joint with bone grafts and fixation devices, it aims to eliminate abnormal and painful motion through the joint. With proper patient selection and post-operative care, SIJF can significantly improve quality of life for many sufferers of sacroiliac joint dysfunction and pain.