Sacroiliac (SI) joint fixation is a minimally invasive procedure to stabilise the sacroiliac joint using screws placed under X-ray guidance. It is performed for traumatic SI joint disruption or sacral fractures as part of pelvic ring injuries.
Under X-ray or CT guidance, one or two large screws are inserted percutaneously (through small skin incisions) across the sacroiliac joint into the sacrum. This stabilises the posterior pelvic ring. The procedure takes approximately one hour.
SI joint fixation is part of the treatment for unstable pelvic ring injuries where the posterior ring is disrupted. The posterior pelvic ring carries 60% of the body's weight through the pelvis, so stabilisation is essential for weight-bearing.
Stable SI joint injuries may be managed with restricted weight-bearing. Unstable injuries require fixation.
CT scan for screw trajectory planning. May be performed urgently.
Stabilisation of the posterior pelvic ring allowing progressive weight-bearing and rehabilitation.
The screw heads may be palpable in the buttock.
Discomfort around the screw site.
L5 and S1 nerve roots are at risk during screw placement. Injury can cause leg weakness or numbness. Risk approximately 2-5%.
The screw may be placed outside the ideal corridor, requiring repositioning.
Failure of the SI joint to stabilise.
Pin-site or deep infection.
General anaesthesia. Positioned prone or supine.
Weight-bearing restrictions for six to twelve weeks depending on the pelvic ring injury pattern. Crutches or frame for mobilisation. Physiotherapy for hip and core strengthening.
X-rays at six weeks and three months.
No, SI joint fixation is minimally invasive — performed through small incisions under X-ray guidance. However, the underlying pelvic injury is significant.