Sacroiliac Joint Injection

Acute or chronic strain or capsulitis

Causes and findings:
• Acute sacroiliitis
• Ankylosing spondylitis
• Chronic ligamentous pain after successful manipulation
• Usually female - often pre- or post-partum or traumatic incident such as fall onto buttocks
• Pain over buttock, groin or occasionally down posterior thigh to calf
• Pain after rest, or long periods of sitting or standing
• Pain on stressing: posterior ligaments in hip flexion, oblique adduction and transversely anterior ligaments in Faber or 4 test (hip flexion, abduction and external rotation)

Equipment:
Syringe - 2 ml
Needle - 22G 3-3.5 inches (75-90mm) spinal
Kenalog 40 - 20 mg
Lidocaine - 1.5 ml 2%
Total volume - 2 ml

Anatomy:
The sacroiliac joint surfaces are angled obliquely posteroanteriorly, with the angle being more acute in the female. The dimples at the top of the buttocks indicate the position of the posterior superior iliac spines. The easiest entry point is usually found in a dip just below and slightly medial to the spines.

Technique
• Patient lies prone over small pillow
• Identify and mark posterior superior iliac spine on affected side
• Insert needle a thumb's width medial and just below this bony landmark at level of second sacral spinous process
• Angle needle obliquely antero-laterally at an angle of about 45 °
• Pass needle between sacrum and ilium until a ligamentous resistance is felt.
• Inject solution as a bolus within joint if possible, or pepper posterior capsule

Aftercare:
Movement within the pain-free range is encouraged - a lunging motion with the foot up on a chair can help relieve pain, as can moderate walking. The patient should avoid hip abduction positions and sit correctly. A temporary belt is worn if the joint is unstable, and sclerosing injections can be given to increase stability.

Comments:
This is not a very common injection; usually manipulation, mobilization and exercise techniques clear the majority of chronic sacroiliac joint symptoms. The needle often comes up against bone when attempting this injection and then has to be manoeuvred around to allow for the variations in bony shape before entering the joint space. It is unusual to have to repeat this injection and the joint can often be successfully manipulated if necessary a week later if necessary.