Short answer. For a short time, yes. A cortisone injection can ease a flare of knee pain for a few weeks. The effect fades, and repeated injections on a fixed schedule may not be good for the joint.

Evidence grade. Probably helps a little, for a short time.

What it is

Cortisone is a medicine that calms inflammation. The type used in joints is a corticosteroid. It is not the same as the steroids taken by bodybuilders. A doctor injects it into the knee, often with local anaesthetic, sometimes with an ultrasound scan to guide the needle.

What the research shows

A Cochrane review pooled 27 trials with 1,767 adults with knee arthritis. Pain relief was small to moderate at one to two weeks and again at four to six weeks. There was no sign of a benefit at six months. The reviewers rated the quality of the evidence as low, because most trials were small and had weaknesses.¹

One well run trial tested a different use. It gave 140 adults a cortisone injection or a salt water injection every 12 weeks for two years. Pain was no better in the cortisone group. Knee cartilage thinned about twice as much on MRI in the cortisone group.² It is not known whether this extra loss matters in daily life, but it is a reason to avoid injections on a fixed schedule.

Risks and effort

A sore knee for a day or two after the injection is common. Infection is rare. In people with diabetes, blood sugar can run higher for a few days, so check it more often. Tell your surgeon about any recent injection if you are planning a knee replacement, because some surgeons prefer a gap between the two.

What usually works instead

Exercise and strength work for the leg muscles, weight loss where that applies, and simple pain relief have the best long term evidence. Cortisone works best as a way to settle a bad flare so that you can get on with the exercise. See Osteoarthritis of the Knee and Does exercise work for knee arthritis?.

Questions people ask

How many cortisone injections can I have?

There is no agreed safe number. Most doctors keep injections for flares and avoid giving them regularly. If you need them often, that is a sign the knee needs a different plan.

How long will it last?

For most people the benefit lasts from a few weeks to a couple of months. In the trials, the effect had gone by six months.

Will it damage my knee?

One or two injections for a flare have not been shown to cause harm. The cartilage loss seen in the trial came from injections every 12 weeks for two years.

Is cortisone the same as the steroids athletes misuse?

No. Cortisone type medicines are a different group from anabolic steroids, and they do not build muscle.

References

Jüni P, Hari R, Rutjes AWS, Fischer R, Silletta MG, Reichenbach S, da Costa BR. Intra-articular corticosteroid for knee osteoarthritis. Cochrane Database Syst Rev. 2015;(10):CD005328. https://doi.org/10.1002/14651858.CD005328.pub3
McAlindon TE, LaValley MP, Harvey WF, Price LL, Driban JB, Zhang M, Ward RJ. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: a randomized clinical trial. JAMA. 2017;317(19):1967-1975. https://doi.org/10.1001/jama.2017.5283

Last reviewed 22 October 2026. Next review due October 2028.