Platelet-Rich Plasma (PRP) Injections for Knee Arthritis

If knee pain is limiting your daily life, you’re not alone. Millions of people experience stiffness, swelling, and discomfort from knee osteoarthritis — the gradual “wear and tear” of the joint over time.

One exciting treatment that’s gained attention in orthopedic medicine is platelet-rich plasma (PRP) therapy. Unlike cortisone shots or surgery, PRP uses your own blood’s healing potential to reduce pain and promote tissue repair naturally.

And now, a new 2025 study published in The American Journal of Sports Medicine (PubMed ID: 39751394) provides strong evidence that PRP truly helps patients with knee arthritis.

PRP stands for platelet-rich plasma — a solution made by drawing a small amount of your blood, spinning it in a centrifuge, and separating the layer rich in platelets.

Platelets are known for helping your body heal injuries. They release growth factors that stimulate repair, reduce inflammation, and support tissue health inside the joint.

Once prepared, this concentrated plasma is injected directly into the knee — where it can help relieve pain and improve joint function.

This new meta-analysis (a study combining the results of multiple clinical trials) reviewed data from 18 randomized controlled trials involving nearly 2,000 patients with knee osteoarthritis.

Here’s what the researchers discovered:

• PRP works better than placebo (saline) for both pain relief and joint function.
• Patients reported meaningful improvement in their ability to walk, climb stairs, and do daily activities.
• The best results appeared between 3 and 6 months after treatment — and many patients maintained benefits for up to a year.
• Higher platelet concentrations (around 1 million platelets per microliter) produced stronger and longer-lasting effects compared to lower doses.

In simple terms: the better the platelet quality, the better the results.

Many people turn to PRP because it offers several advantages:

• It’s minimally invasive — no surgery required.
• It uses your own blood, so allergic reactions are extremely rare.
• It can be repeated safely if symptoms return.
• It may delay the need for joint replacement in early to moderate arthritis.

While PRP isn’t a cure, most patients experience noticeable pain reduction and improved mobility, helping them stay active longer.

A PRP injection is a quick outpatient procedure:

1. A small blood sample is drawn from your arm.
2. The sample is processed in a centrifuge to isolate platelets.
3. The concentrated PRP is injected into your knee under sterile conditions.

The entire process usually takes less than an hour. Most patients return to normal activities the same day, though you may be advised to avoid intense exercise for a few days.

You may be a good candidate for PRP if you have:

• Mild to moderate knee arthritis (before bone-on-bone changes)
• Pain that hasn’t improved with physical therapy, bracing, or medications
• A desire to avoid or postpone surgery

Dr. Kohn can help determine whether PRP is appropriate based on your X-rays, medical history, and activity goals.