Here's my experience - after being diagnosed with the need for a hip replacement.

Mine was a cortisone injection, guided by a fluoroscope to the correct location. Mine was done in a hospital as an outpatient. I had to stop all blood-thinning meds (prescription and OTC like NSAIDs) 3-4 days before the procedure to minimize bleeding.

They prep you by getting you in a gown, positioning you and using an antiseptic scrub multiple times.

They follow this with injections of lidocaine to numb the area - this can be painful (actually the most painful for me), but is necessary to enable the large needle to inject the cortisone.

The actual injection is a bit painful - they slowly work the needle in the proper position to do the injection. When I had the hip done, I could feel the stuff getting pushed in. Not that you can do it, but it does help to relax and definitely don't move!

The lidocaine works about 3-6 hours and wears off, and the cortisone generally takes 3-5 days minimum to start to kick in. So, you may experience more pain for a few days. You will have a bandage which you can remove once the bleeding stops. They recommended taking showers and avoiding soaking in a bathtub/hot tub for a week.

For mine, the pain relief lasted about 90 days. Thus, someday I will be getting a replacement after 2 more injections.

BTW - I just had a similar injection done on the L4 part of the spine where I have a misaligned disk pressing on a nerve. They used an xray rather than a fluoroscope for location. The needle was 3.5 inches long.

I have a followup to the back injection in 6 weeks where we will be discussing doing another injection for the hip. There is a protocol which I believe (based on spousal experience) is three injections before they will consider doing a replacement.

In my opinion it's is better to have it done than to have your physical activities restricted by the pain.

Hopefully this isn't too much information and hope it helps.