Steroid (Cortisone) Injections: The Workhorse of the Clinic

Steroid injections, often called cortisone shots, are one of the oldest and most common treatments in orthopedics. Here is what they do, what the research shows, and the side effects worth knowing about.

Steroid injections are the workhorse of my clinic. They are generally very safe, and for many patients they bring fast relief.

What a steroid injection is

A corticosteroid is a strong anti-inflammatory medicine. We usually mix it with a numbing medicine and inject it directly where the problem is: into an arthritic joint such as the knee, hip or shoulder, or into an inflamed bursa or tendon sheath. Because the medicine goes right to the source, a much smaller dose is needed than with steroid pills.

What the studies show

• Relief is real but short-term. A Cochrane review of 27 trials and 1,767 people with knee arthritis found that steroid injections reduced pain more than placebo, with the clearest benefit 1 to 6 weeks after the injection. By 3 to 6 months, the difference from placebo was no longer clear.

• About 1 in 8 patients improves because of the steroid itself. In that review, about 8 people needed to be treated for one extra person to get a meaningful benefit, beyond what a placebo injection would give.

• Guidelines support them for short-term relief. The American College of Rheumatology strongly recommends steroid injections for knee arthritis. The American Academy of Orthopaedic Surgeons gives them a moderate recommendation, noting the effect typically lasts up to about 3 months.

That makes steroid injections especially useful to calm a painful flare, get through an important event, or make it possible to start physical therapy and strengthening, which give the longest-lasting benefit.

Possible side effects

Most people have no problems, or only minor ones that pass in a few days. Still, it’s important to know what can happen.

In the joint or at the injection site:

• Post-injection flare. Some patients have a temporary increase in knee or joint pain, sometimes with swelling, usually lasting 2 to 3 days. Ice and rest help.

• Skin changes. The skin at the injection site can lighten, or the fat under it can thin, especially with injections close to the surface.

• Infection. Joint infection is rare, reported in about 1 in 14,000 to 1 in 77,000 injections. Call us right away if you develop fever, increasing redness or worsening pain days after an injection.

Effects elsewhere in the body (systemic effects):

• Higher blood sugar. In people with diabetes, a knee injection can raise blood sugar for 2 to 3 days, often above 300 mg/dL. If you have diabetes, check your sugar more often after an injection.

• Facial flushing. Up to about 15% of patients, more often women, notice warmth and redness in the face within hours, lasting up to 3 to 4 days. It is harmless.

• Other short-term effects can include trouble sleeping, increased appetite and mood changes for a few days.

With repeated injections over time:

• In a 2-year trial, a knee steroid injection every 3 months led to slightly more cartilage loss than saltwater injections, with no added pain relief.

• Rarely, steroid injections have been linked to faster joint damage, including rapidly progressive arthritis and small stress fractures beneath the cartilage. This concern is greatest in the hip (see below).

A side note about hip injections

The hip deserves special mention. It sits deep in the body, so hip injections are usually done with X-ray or ultrasound guidance. And over the past several years, studies have raised a specific concern: rapid collapse of the hip joint after a steroid injection.

• Rapidly destructive hip disease. The largest study, from Kaiser Permanente in Hawaii and published in 2021, looked at 688 hips that received a steroid injection. 37 of them (5.4%) developed rapidly destructive hip disease, on average about 5 months after the injection, and all of those patients went on to hip replacement. In the same study, hips that had been injected were about 8.5 times more likely to develop the condition.

• The dose and number of injections matter. In that study, the estimated risk was about 2% after a single low-dose injection, about 5% after several low-dose injections or one high-dose injection, and up to about 10% after several high-dose injections.

• Rapid osteonecrosis (AVN). A Massachusetts General Hospital study presented in 2017 found new osteonecrosis, or death of bone in the ball of the hip, in 22% to 24% of hips 3 to 9 months after a steroid injection, compared with 5% to 9% of hips that were not injected. Collapse of the ball of the hip was seen in 15% to 17% of injected hips, compared with 4% of controls.

• Not every study agrees. A 2021 study from the same hospital matched injected and non-injected hips by age, weight and severity of arthritis, and excluded hips that already had bone damage on MRI. With those factors accounted for, the rates were similar: arthritis progression in 3.2% of both groups, and new collapse in 3.2% versus 2.2%.

These studies show an association, not proof that the steroid causes the damage. People who need a hip injection often already have a hip that is worsening. Still, the findings are why we:

• Use a low steroid dose for hip injections

• Avoid repeated hip injections when possible

• Discuss this risk with you before a hip injection

• Take a new X-ray if hip pain gets much worse in the weeks or months after an injection

How we keep steroid injections safe

• Spacing them out. We generally give no more than one injection in the same joint every 3 months.

• Timing around surgery. A steroid injection within 3 months before a knee replacement is linked to a higher risk of infection after surgery, so we avoid injecting a joint in the 3 months before replacing it.

• Watching blood sugar. If you have diabetes, we’ll talk about monitoring your sugar for a few days afterward.

• Pairing them with strengthening. An injection works best as a window to get stronger, not as the whole plan.

Other options

For patients who need longer relief, want to avoid steroids, or can’t have them, other injections may fit better. You can read about them in PRP Injections for Arthritis and Tendon Pain and Hyaluronic Acid Injections for Knee Arthritis. And for the foundation of any plan, see Stronger Knees Are Functional Knees. If you’re wondering whether a steroid injection is right for you, book a visit and we’ll go over your options.

References

• Jüni P, et al. Intra-articular corticosteroid for knee osteoarthritis. Cochrane Database Syst Rev. 2015;(10):CD005328.

• da Costa BR, Hari R, Jüni P. Intra-articular corticosteroids for osteoarthritis of the knee. JAMA. 2016;316(24):2671-2672.

• Kolasinski SL, et al. 2019 ACR/Arthritis Foundation guideline for the management of osteoarthritis of the hand, hip, and knee. Arthritis Care Res. 2020;72(2):149-162.

• American Academy of Orthopaedic Surgeons. Management of Osteoarthritis of the Knee (Non-Arthroplasty) Clinical Practice Guideline, 3rd ed. 2021.

• Jones T, Kelsberg G. Intra-articular corticosteroid injections for osteoarthritis of the knee. Am Fam Physician. 2014;90(2):115-116.

• Habib G, Safia A. The effect of intra-articular injection of betamethasone on blood glucose levels in controlled diabetic patients with symptomatic osteoarthritis of the knee. Clin Rheumatol. 2009.

• McAlindon TE, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis. JAMA. 2017;317(19):1967-1975.

• Kompel AJ, et al. Intra-articular corticosteroid injections in the hip and knee: perhaps not as safe as we thought? Radiology. 2019;293(3):656-663.

• Okike K, et al. Rapidly destructive hip disease following intra-articular corticosteroid injection of the hip. J Bone Joint Surg Am. 2021;103(22):2070-2079.

• Chang CY, Simeone FJ, et al. Hip steroid injections associated with bone changes. RSNA Annual Meeting 2017 (press release).

• Abraham PF, et al. Safety of intra-articular hip corticosteroid injections: a matched-pair cohort study. Orthop J Sports Med. 2021;9(10):23259671211035099.

• Kim YM, Joo YB, Song JH. Preoperative intra-articular steroid injections within 3 months increase the risk of periprosthetic joint infection in total knee arthroplasty: a systematic review and meta-analysis. J Orthop Surg Res. 2023;18(1):148.