What is a facet joint?

Behind each disc sit two small joints, one on each side. They are built just like the joints in your fingers: cartilage on both surfaces, a capsule around the outside, and a synovial lining that makes fluid. They guide the spine’s motion and stop it from sliding. They carry more load when you arch or twist. They carry more still as the disc in front of them dries out and loses height. What is true of a knee is true here. The cartilage wears, the lining inflames, and the capsule stretches and fills with nerve endings. And the joint hurts at rest as well as under load.

Why does a facet joint flare up?

Wear alone does not flare. Wear plus synovitis does. The first driver is mechanical. Bits of worn cartilage irritate the lining, which swells and pours out inflammatory fluid. A joint that was quietly arthritic for a decade suddenly cannot be arched or turned. The second driver is body-wide, and most spine clinics skip it. Osteoarthritis is more and more understood as a metabolic disease. An insulin-resistant, inflamed body runs higher levels of the same cytokines (inflammation signals) the joint lining makes. Fat tissue sends out signals that sensitize cartilage and nerve. So the joint’s inflammation starts from a higher floor. In a large CT series, body mass index tracked with facet joint osteoarthritis. The third driver is the load a person actually puts through the joint: overhead line work, drywall, the steel and refinery trades, an Alton farmer stepping off a tractor two hundred times a day, and the sleep debt of a rotating shift. The injection reaches the first. The plan has to reach all three.

When steroid in the joint is the right call

Are facet joint injections worth it?

The trials on steroid inside the facet joint are older and thinner than the trials on blocking or ablating its nerves. We say so before you agree to it. The 1991 New England Journal trial randomized patients with a positive facet block to steroid or saline in the joint. It found no meaningful difference at one month, and only a modest, partly explained difference at six. A 2013 Spine trial compared steroid in the joint with steroid given as an intramuscular injection (a shot into muscle). Both groups improved. The joint group came out ahead on several measures of function and medication use. That supports aiming the drug at the joint, not the muscle beside it. The 2020 multispecialty consensus guidelines rate the evidence for intra-articular (inside the joint) steroid as low. They save it for patients with an inflammatory picture. The ASIPP guidelines of the same year reach a similar place.

Read the populations. Those trials enrolled long-standing chronic back pain, not acute flares. None sorted patients by whether the joint showed synovitis on imaging, which is exactly the patient this injection is for. So the practice position is narrow on purpose: a flare or a cyst, an imaged joint, one injection judged on its own result, and the block-and-ablation pathway for anything that keeps coming back. Steroid is a whole-body drug given in one spot. It raises blood glucose for days in a diabetic patient. How many you get is a clinical decision made each time against what the last one did. It is never a course booked in advance.

How is a facet injection different from a nerve block or radiofrequency ablation?

Three procedures touch this joint, and patients are routinely told they are interchangeable. A medial branch block numbs the two nerves outside the joint for a few hours. It tests whether the joint is the pain source. Radiofrequency ablation heats those nerves for months once two blocks agree. The injection on this page treats the inside of the joint and replaces neither. As a test, steroid in the joint can leak onto the nerves and give a false positive. And it cannot give the durable answer the ablation gives. Ask which of the three is proposed and why. If the answer is “we always start with the injection,” that is a schedule, not a diagnosis.

For the patient driving in from Illinois

One visit for the injection, no sedation, and you drive yourself home over the bridge; normal activity, including work, returns within two to four hours. The result is judged at about two weeks, and that check is usually a phone call rather than a second crossing. With clear roads and no traffic figured in, Wood River is about 30 minutes from the office, Godfrey about 40, Columbia about 45. Bring your imaging. If the report says facet arthropathy but the pictures show no inflamed joint, we will say so and talk about the block instead.

What happens during a facet joint injection?

Frequently asked questions

Is a facet injection the same as an epidural?

An epidural steroid injection puts medication in the space around a nerve root, for pain that travels down a limb, while a facet injection goes inside a joint for pain that stays in the back or neck. They treat different structures. One does not stand in for the other.

How is it different from a medial branch block?

The block is a timed test on the nerves outside the joint and carries no steroid, while this injection is a treatment inside the joint. The difference, and why it matters, is the subject of our medial branch block page.

How many facet injections can I have?

Each one is decided against what the last one did and against your total steroid exposure. A joint that keeps needing steroid should be blocked and ablated instead. That is the argument on when injections stop working.

My MRI says facet arthropathy. Does that mean I need this?

Arthropathy (joint change) on a scan shows up in nearly everyone past sixty. By itself it does not mean the joint hurts. What does is the pattern described on our facet joint pain page, confirmed by exam and, usually, by a block.

I have diabetes. Is the steroid a problem?

Your glucose will likely run high for several days. An insulin-resistant body also inflames the joint more easily. So that talk is part of the visit, not a footnote. The reasoning is on metabolic health and pain.

How painful is a facet joint injection?

Expect pressure more than pain. The skin is numbed first, then a fine needle is guided into the joint under live X-ray. When the medication goes in you may feel pressure and, now and then, a brief return of your usual ache. There is no sedation, so you are awake the whole time and drive yourself home afterward.

Is a facet joint injection the same as a cortisone shot?

It is a steroid shot, but aimed. A small dose of steroid and numbing medicine is placed inside the joint. First, a drop of contrast dye proves the needle tip is in the joint and not in the muscle beside it. A 2013 trial found that steroid in the joint beat the same steroid given into muscle on several measures of function and medication use.

What is the next step if a facet joint injection does not work?

The block-and-ablation pathway. A medial branch block numbs the two small nerves outside the joint for a few hours. It tests whether the joint is really the source. When two blocks agree, radiofrequency ablation heats those nerves and gives relief measured in months. A joint that keeps needing steroid should be blocked and ablated instead.

What should I expect after a facet joint injection?

You drive yourself home, and normal activity, including work, returns within two to four hours. The steroid builds over several days. We check the result at about two weeks, usually by phone. If you have diabetes, expect your blood sugar to run high for several days and check it more often.

Related reading

• Facet joint pain
• Medial branch block
• Radiofrequency ablation
• Image-guided joint injections
• Knee pain