Glossary
Platelet-rich plasma (PRP)
Quick answer
Platelet-rich plasma is a concentrate made from your own blood, spun to collect platelets and their growth factors, then injected into the knee to ease pain and inflammation. Evidence is most supportive in mild to moderate osteoarthritis, says Dr. Pablo Gelber, knee surgeon at Aman Hospital in Doha, Qatar.
What it is
A sample of blood is drawn from your arm and processed in a centrifuge, which separates the platelet-rich layer from red cells. That layer is then injected into the joint, or around a tendon, usually with ultrasound guidance when the target is outside the joint. Preparation methods vary, which partly explains differences between studies.
Some protocols use a single injection; others use a short series a few weeks apart.
Why it matters for patients
In knee osteoarthritis, several studies suggest PRP can reduce pain and improve function for some months, in some trials more than hyaluronic acid or steroid injections, especially in earlier disease. Results are less consistent for tendon problems such as jumper's knee.
PRP does not regrow worn cartilage or reverse arthritis, and it does not suit everyone. Because it comes from your own blood, serious reactions are rare, though the knee can be sore and swollen for a few days.
How it is decided
It is considered when pain persists despite exercise, weight management and simple medicines, and when X-rays show the stage of arthritis. Anti-inflammatory tablets are often paused around the injection. Insurance coverage varies, so check with your insurer and Aman Hospital.
Frequently asked questions
How soon does PRP start to work?
Any benefit usually builds over several weeks rather than days. A post-injection flare for 24 to 48 hours is common.
Can I exercise after a PRP injection?
Light activity and walking are usually fine after a day or two. Heavy or high-impact exercise is typically avoided for about a week, depending on what was injected.
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