If you have a painful knee, shoulder or elbow, your doctor may suggest an injection. The two most common choices are cortisone (a steroid) and PRP (platelet-rich plasma). They're used for many of the same problems, but they work in very different ways.
How cortisone works
Cortisone is a powerful anti-inflammatory. It quiets inflammation in a joint, bursa or tendon sheath, which can bring relief within days. It doesn't repair tissue, and repeated injections into the same area are usually limited because of possible effects on cartilage and tendons.
How PRP works
PRP is made from your own blood. Platelets are concentrated in a centrifuge and injected into the injured area, with the goal of supporting the body's healing response. Improvement is gradual, usually over 4 to 12 weeks.
Side-by-side comparison
- Speed of relief: Cortisone is faster, often within days. PRP builds over weeks.
- How long relief lasts: Cortisone often wears off in weeks to a few months. In several studies of tennis elbow and knee arthritis, PRP showed longer-lasting benefit.
- Repeat injections: Cortisone is usually limited to a few per year in one area. PRP can be repeated.
- Cost: Cortisone is usually covered by insurance. PRP usually is not and is paid out of pocket.
- Side effects: Cortisone can temporarily raise blood sugar and may weaken tissue with repeated use. PRP commonly causes a few days of soreness.
Which conditions is each best for?
Cortisone is often a good choice for acute flares, bursitis, frozen shoulder and short-term relief. PRP is most studied for chronic tendon problems such as tennis elbow, and for mild to moderate knee arthritis. Many specialists use both at different stages of care.
The bottom line
If you need fast relief from a flare, cortisone may make sense. If you have a long-standing tendon or arthritis problem and want to avoid repeated steroid shots or surgery, PRP is worth discussing. Read our PRP therapy guide for questions to ask a provider.
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This article is for general information only and is not medical advice. Talk with a qualified physician about your diagnosis and treatment options.
