Platelet-rich plasma (PRP) for knee pain has moved from the sidelines of sports medicine into mainstream orthopedic and pain practice. If you have knee osteoarthritis or a chronic knee injury and want to avoid — or delay — surgery, you have probably come across PRP as an option. But does it actually work, and is it right for you? Below, Dr. Rainier Guiang, MD, a board-certified pain specialist at University Pain Consultants in Riverside and Menifee, California, explains what the evidence shows.
What is PRP, and how does it treat knee pain?
PRP is a biologic injection made from your own blood. A small sample (typically 30–60 mL) is drawn and spun in a centrifuge to concentrate the platelets — the cells that carry growth factors such as PDGF, TGF-beta, VEGF, and IGF-1. When injected into an arthritic or injured knee under ultrasound or fluoroscopic guidance, this concentrated dose of growth factors is thought to reduce inflammation, slow cartilage breakdown, and stimulate the joint’s own repair processes.
Because PRP is autologous — derived entirely from your own blood — there is no risk of allergic reaction, rejection, or disease transmission.
Does PRP work for knee osteoarthritis? What the research shows
The strongest evidence for PRP anywhere in the body is for knee osteoarthritis. A 2024 meta-analysis by Di Matteo and colleagues in the American Journal of Sports Medicine pooled multiple randomized controlled trials and found that PRP produced clinically meaningful improvements in pain and function at 1, 3, 6, and 12 months — exceeding the threshold for a clinically important difference, while placebo injections did not.
Head-to-head studies are also encouraging. Multiple randomized trials and meta-analyses have found PRP outperforms corticosteroid (cortisone) and hyaluronic acid injections for knee osteoarthritis at 6- and 12-month follow-up, with relief that tends to last considerably longer.
PRP vs. cortisone for the knee
Cortisone injections can relieve knee pain quickly, but the relief is usually short-lived (often 4–8 weeks), and there is growing concern that repeated cortisone injections may accelerate cartilage loss over time. PRP works differently: instead of simply suppressing inflammation, it aims to support the joint’s repair biology. Relief typically develops more gradually — over weeks — but tends to last longer, frequently beyond 12 months in people who respond.
What to expect during PRP treatment
The procedure is done in-office and usually takes 45–90 minutes:
- A small amount of blood is drawn from your arm.
- The blood is spun in a centrifuge to concentrate the platelets.
- The PRP is injected into the knee under ultrasound or fluoroscopic guidance for accuracy.
Most people return to light activity the same day. A temporary flare of soreness for 2–5 days is common and expected as the healing response begins.
Who is a good candidate for PRP knee injections?
PRP tends to work best for mild-to-moderate knee osteoarthritis and chronic tendon or ligament injuries around the knee, such as patellar tendinopathy (“jumper’s knee”). It is less likely to help end-stage, bone-on-bone arthritis, where joint replacement may be more appropriate. A physician evaluation is the best way to determine whether you are a candidate.
How long until I see results, and how long do they last?
Most people notice gradual improvement over 4–8 weeks as tissue repair progresses, with benefits often peaking at 3–6 months. In responders, relief commonly lasts beyond 12 months, and treatment can be repeated safely. About 20–30% of patients do not respond, and results are never guaranteed.
Frequently asked questions about PRP for knee pain
Is PRP for knee pain covered by insurance?
In most cases, no. PRP is generally considered elective and is paid out of pocket. We review pricing transparently at your consultation.
Is PRP safe?
PRP has an excellent safety profile because it uses your own blood. The most common side effect is temporary soreness at the injection site. Serious complications such as infection are rare (under 0.1%) with sterile, image-guided technique.
How many treatments will I need?
Some people do well with a single injection; others benefit from a short series. Your physician will recommend a protocol based on your diagnosis and response.
Considering PRP for your knee?
Dr. Rainier Guiang, MD is a board-certified anesthesiologist and pain specialist who performs all PRP injections personally, under image guidance, at University Pain Consultants in Riverside and Menifee, CA. Learn more on our PRP & PRF therapy for pain page, or book a $95 telemedicine consultation to find out whether PRP is right for your knee. The consultation fee is credited toward any treatment you choose.
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. PRP results vary between individuals and are not guaranteed. Treatment decisions are made on an individual basis after a comprehensive medical evaluation.
