A bursa injection delivers a combination of a steroid and a numbing agent directly into an inflamed bursa, one of the small fluid-filled sacs that cushion your joints. The goal is to reduce swelling and pain when other treatments like rest, ice, or physical therapy haven’t provided enough relief. It’s one of the most common procedures for bursitis in the hip, shoulder, and knee, and it typically takes just a few minutes in a clinic or office setting.
How a Bursa Injection Works
Bursae act as cushions between bones, tendons, and muscles around your joints. When a bursa becomes irritated or inflamed, the resulting pain and stiffness can make everyday movements difficult. A bursa injection targets that inflammation at its source.
The steroid component works by narrowing blood vessels in the area, which limits swelling. It also blocks the buildup of immune cells that flood the injury site and slows the release of chemicals called prostaglandins that drive the inflammatory cycle. The numbing agent mixed in provides immediate but short-lived pain relief, usually lasting about two hours, while the steroid takes a few days to kick in.
Where Bursa Injections Are Most Common
The three most frequent sites are the hip (specifically the greater trochanteric bursa on the outer hip), the shoulder (the subacromial bursa beneath the top of the shoulder blade), and the knee. Hip bursitis is particularly common in women and people in their mid-50s and older. Shoulder bursitis often develops alongside rotator cuff problems. The same injection approach applies regardless of location, though the positioning and needle depth will differ.
What the Procedure Feels Like
You’ll be positioned so the provider can easily access the affected joint. For a hip injection, that means lying on your back; for a shoulder injection, you may be seated. The provider locates the bursa either by feeling for anatomical landmarks or by using ultrasound imaging to visualize the exact spot.
First, a small amount of numbing medication is injected into the skin to reduce discomfort from the main needle. Then a longer needle is guided to the bursa, and the steroid-anesthetic mixture is injected. You may feel pressure or a brief sting, but the procedure itself is over in minutes. A bandage goes on, and you can go home the same day. Most providers recommend taking it easy for 24 to 48 hours afterward and avoiding strenuous use of the joint.
Ultrasound Guidance Improves Accuracy
Some providers perform bursa injections using only physical landmarks to guide needle placement, while others use ultrasound imaging in real time. Ultrasound-guided injections have been shown to be more accurate, and that accuracy can make a meaningful difference in outcomes. One study of hip bursitis injections found that when the needle landed precisely in the trochanteric bursa under ultrasound guidance, patients experienced a statistically significant decrease in pain. When the injection ended up in a nearby but different bursa, there was no measurable improvement. If you’re scheduling a bursa injection, it’s worth asking whether ultrasound guidance is available.
How Quickly You’ll Feel Relief
The numbing agent provides comfort for the first couple of hours, but once it wears off, your pain may return or even temporarily worsen. The steroid needs time to suppress inflammation. About half of patients notice meaningful improvement within three days of the injection, and over 90% experience relief within a week. If you happen to get a post-injection pain flare (more on that below), relief tends to take a bit longer, averaging around four and a half days compared to three days without a flare.
In terms of how long the benefits last, most studies show pain reduction holding for three to six months. Long-term pain relief beyond that is limited for many patients, which is why bursa injections are often used alongside physical therapy and activity modifications rather than as a standalone fix.
Success Rates
The effectiveness of bursa injections varies, but the overall picture is positive. For trochanteric (hip) bursitis, studies report symptom resolution and return to normal activity in 49% to 100% of patients. That wide range reflects differences in how severe the bursitis was, whether patients also did physical therapy, and how “success” was defined. In several case series, two-thirds or more of patients saw significant improvement, and some smaller studies reported complete pain resolution. Patients who don’t respond to one or two injections may need to explore other options.
Post-Injection Flare
One of the most common side effects is a “cortisone flare,” a temporary spike in pain at the injection site. About one in three patients experiences this after shoulder injections, and rates are similar at other sites. More than half of flares begin within 30 minutes of the injection rather than hours later, which can be alarming if you’re not expecting it. The likely cause is the steroid crystals themselves irritating the tissue before the anti-inflammatory effect takes hold.
The good news is that flares are self-limiting. About half of people who get a flare feel better by the end of the same day. For the rest, symptoms last an average of just under four days, with a maximum of about a week. Ice and over-the-counter pain relievers can help you ride it out.
Risks and Side Effects
Compared to steroid medications taken by mouth, localized bursa injections carry a very low complication rate, estimated at less than 1% for serious problems. The potential side effects include:
- Skin lightening at the injection site, reported in roughly 1% to 4% of patients. It typically appears one to four months after the injection and resolves on its own within six to 30 months.
- Fat thinning under the skin near the injection site, which can create a small visible dent. This is usually reversible within a year.
- Infection is rare but possible any time a needle breaks the skin.
- Temporary facial flushing, which some patients notice for a day or two.
- Tendon weakening is a concern if repeated injections are given near tendons, which is one reason providers limit how often you can get them.
How Often You Can Get Them
Current guidelines recommend spacing steroid injections at the same site no closer than every three months. Most providers will limit you to three or four injections per site per year. Repeated steroid exposure can weaken surrounding soft tissue over time, so these injections work best as part of a broader treatment plan rather than something you rely on indefinitely. If you find yourself needing injections frequently to manage pain, that’s typically a signal to reassess with your provider whether a different approach might be more effective.