Hip Air Arthrogram and Steroid Injection

I perform steroid injections for my patients to treat hip pain. When the pain is coming from inside the hip joint,such as in cases of osteoarthritis, avascular necrosis, hip impingement, or labral tear, an intra-articular injection is indicated. These injections are performed with fluoroscopic guidance (using a real-time x-ray machine). Usually intra-articular contrast is used to verify position of the needle.
I prefer to inject air rather than commercial contrast material since I believe that air is safer. Other doctors ask me how I can be sure that the injection is going in the right place with just using air, they ask how can you see the air. Here is an example of a recent patient with an air arthrogram of the hip:

Right Hip Air Arthrogram

As can be seen in the above images, the right side shows air injected into the inferior region of the femoral neck. The air then naturally travels to the inferior region of the hip joint and encircles the hip joint in the area just outside the labrum This is seen as a lighter density coming from the inferior hip and heading in a direction up and lateral, approximately perpendicular to the femoral neck.
In this case the patient was highly satisfied with the steroid injection and had relief of hip pain.