By Mr Ahmed-Ramadan Sadek, Neurosurgeon · Last reviewed October 2026 · 6 min read

What are facet joints?

Your lower back (lumbar spine) is built from five vertebrae stacked on top of each other, with a cushioning disc between each pair. At the back of every level sits a pair of small interlocking joints called facet joints, one on each side. They glide against each other as you bend forwards, lean back and twist.

Like the knee or hip, each facet joint is lined with smooth cartilage and wrapped in a thin capsule containing lubricating fluid. That capsule is well supplied with nerve endings, which is why an irritated facet joint can be so painful.

What is facet joint pain?

As we age, the discs gradually dry out and lose height (see degenerative disc disease). This shifts more of the body’s weight onto the facet joints. Weak core muscles and carrying extra weight add to that load. Over time the cartilage wears, arthritis develops and the joints can become inflamed. Doctors sometimes call the resulting pattern of pain and muscle spasm facet syndrome.

Typical features

• aching low in the back, which may spread over the hips into the groin or upper thighs, roughly where your hands rest when you slip them into your front trouser pockets;
• stiffness that is worst first thing in the morning or after sitting or standing still for a while, easing once you get moving;
• pain on twisting or leaning backwards;
• sudden spasms when moving too quickly, the sort of episode people describe as their back “going”;
• symptoms that come and go over weeks or months.

Because the pain can reach the groin and thigh, it is sometimes mistaken for a hip problem. Unlike sciatica, facet pain does not usually travel below the knee.

Who might benefit from an injection?

Most episodes of back pain settle with time, activity, pain relief and physiotherapy (see acute back pain). An injection may be considered when symptoms have dragged on and are interfering with daily life despite these measures.

A facet injection has two possible purposes:

• Treatment: a steroid (anti-inflammatory) is placed directly into the irritated joint to settle the inflammation.
• Diagnosis: if your pain improves after the injection, even briefly, this strongly suggests the facet joints are the source, which helps guide further treatment.

Before the procedure

• Tell your team if you take blood-thinning medicines such as warfarin, rivaroxaban or clopidogrel. You may need to pause them. If your appointment comes at short notice, check promptly which medicines need stopping.
• Let them know if you have diabetes, an allergy, or a skin condition such as eczema or psoriasis on your back.
• If you are having sedation, arrange for an adult to collect you and stay with you overnight.

On the day

1. You will have either a local anaesthetic to numb the skin or sedation through a vein so that you are drowsy or asleep.
2. You lie on your front, head turned to one side on a pillow, and the skin is cleaned with antiseptic.
3. Using live X-ray to steer the needle, the doctor guides it into the capsule of each joint being treated.
4. A small dose of steroid and/or local anaesthetic is injected. Each joint takes only a few minutes.

Afterwards a nurse monitors your blood pressure and pulse briefly. It is a day-case procedure and most people head home within a couple of hours.

After the injection

• The area may feel numb for a few hours. When this wears off, pain often comes back for a while, occasionally worse than before, until the steroid starts working, which can take several days to a few weeks.
• Keep taking your usual painkillers until you notice improvement. Do not stop morphine-type drugs or nerve-pain medicines (gabapentin, pregabalin, amitriptyline) suddenly; your GP can help you taper them.
• The British Association of Spine Surgeons (BASS) advises no driving for 48 hours after sedation.
• You may need the next day off work, or longer if the pain persists.

How well does it work?

The BASS facet joint injection booklet states that 80% of patients experience significant benefit. How long it lasts varies widely, from a few weeks to several years. For many people the relief makes it possible to exercise, stay active and lose weight if needed, which all protect the back.

Facet pain can return. If the first injection helped, it can generally be repeated, but BASS notes that most specialists wait at least six months. If you have not improved by around six weeks, or relief was short-lived, you may be referred to a pain clinic to discuss other options.

Risks and complications

BASS describes facet joint injections as carrying very few risks and does not give numerical rates for them. The uncommon complications it lists are:

Risk	What it means
Bleeding	Very uncommon; more likely if you take blood thinners.
Infection	Rare; more likely if the skin on your back is broken or inflamed.
Steroid side effects	Temporary flushing of the face; in women, changes to periods or post-menopausal bleeding.
Raised blood sugar	For a few days in people with diabetes.
Dural puncture	Rarely the needle nicks the membrane around the nerves, causing a leak of spinal fluid and a headache on standing for a few days; lying flat helps.
Reduced effect	Bony overgrowth can make it hard to place the needle accurately, so relief may be less.

When to get help after your injection

Contact your hospital team or GP promptly if you develop increasing redness, heat or discharge at the injection site, a high temperature, or a severe headache that does not ease when lying down.

• BASS patient booklet: Lumbar Facet Joint Injection
• Spinemathema: Nerve root injections
• Spinemathema: Sacroiliac joint pain

This guide is general information and is not a substitute for advice about your own situation. Please speak to your GP or specialist.