Osteoarthritis Clinic · Injection guide

Corticosteroid injection (Depo-Medrol)

A steroid injection can calm an inflamed, painful joint and ease pain for a while. Here is what it is, what it can and cannot do, the risks with numbers, and how to care for the joint afterward.

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What it is

Depo-Medrol (methylprednisolone acetate) is a long-acting corticosteroid injected directly into the joint. It calms the immune response that drives swelling and pain in osteoarthritis. It treats symptoms. It does not repair cartilage or cure the arthritis. It is used for short-term relief, usually when exercise, weight management, and simple pain relief have not been enough. For a large joint like the knee, the usual dose is 20 to 80 mg, and injections are generally spaced 4 to 6 months apart.

What the evidence shows

For many people, a steroid injection eases pain and helps the joint move better, often within 24 to 48 hours, especially during a flare. The relief is usually short-term, commonly fading over a few weeks to a couple of months. Guideline groups including the American College of Rheumatology and OARSI list it as a reasonable option for short-term relief, not as an ongoing treatment. By easing pain, it can also help you take part more fully in physiotherapy.

The risks, in numbers

Serious problems are uncommon, and local reactions are the usual ones. Based on the published literature:

RiskHow often, and what it means
Post-injection flareThe most common effect. A day or two of increased pain or swelling as it settles, sometimes called a steroid flare. Local reactions like this are reported in roughly 2 to 10 in 100 injections.
Raised blood sugarCommon and short-lived. If you have diabetes, check your levels more often for a few days.
Infection (septic arthritis)Rare. Large studies put it at around or under 1 in 1,000 injections, with older estimates from about 1 in 3,000 to 1 in 50,000. It can appear days to a few weeks later, which is why the fever and hot-joint warnings below matter.
Skin or fat changesUncommon. Thinning, a small dimple, or lightening of the skin near the injection site.
Cartilage, with frequent useHaving more than three or four injections a year in the same joint may affect cartilage over time, so we space them out.

After your injection

  • Rest the joint and avoid hard or prolonged use for 24 to 48 hours.
  • Use an ice pack for 10 to 15 minutes every 2 to 3 hours if the joint is sore or swollen, with a thin cloth against the skin.
  • Keep the injection site clean and dry.
  • Acetaminophen (Tylenol) is usually fine for soreness. Avoid anti-inflammatory tablets (NSAIDs) for the first 24 hours unless your provider has told you otherwise.
  • If you have diabetes, monitor your blood sugar more closely for 3 to 5 days.
  • Ease back into light activity as comfort allows. The injection works best paired with exercise and weight management.

The injection aftercare guide has the full version of this advice. For gentle exercises to do at home as the joint settles, see the knee home exercise programme.

!When to seek urgent care. Call the clinic or seek care if the joint becomes hot, very swollen, or increasingly painful more than 48 hours after the injection, if redness spreads, or if you develop a fever above 38°C (100.4°F). These can be signs of infection, which is rare but needs prompt attention.
This is general information, not medical advice. Whether a steroid injection is right for you depends on your joint, your health, and your goals. Your clinician will talk this through with you.