Palpate the dorsalis pedis artery and mark its course -- avoid injection in this area.
We prefer the anterolateral approach. Avoid tendons, which are usually palpable.
Localize the lateral gutter of the tibiotalar joint and mark the planned injection site.
After antiseptic preparation of the skin, drape the area with sterile towels.
Prepare the local anesthetic solution.
Prepare the MR arthrography contrast solution.
Anesthetize the planned needle tract.
Advance the needle toward the lateral gutter of the tibiotalar joint with the patient in AP (mortise) positioning.
If there is any doubt about intra-articular position of the needle, you can assist the patient in turning the ankle 90 degrees, and check the needle tip position fluoroscopically. Then reposition the ankle in the AP position.
Attach the contrast-filled tubing and syringe to the needle, taking care to eliminate any visible gas in the needle hub.
Slowly inject contrast -- it should flow freely away from the needle tip, outlining the tibiotalar joint.
Document the intra-articular position of your needle and injection with fluoroscopic spot views.