Maybe, but the evidence is MIXED. Some studies of PRP for knee arthritis look promising. The largest well-run trial against a fake (salt water) injection found no difference in pain or cartilage after a year.
US guideline groups don’t agree. Orthopedic surgeons say it may help, but rate the evidence as limited. Rheumatologists, in their latest guidance, strongly recommend against it. A rehab medicine group supports trying it for mild to moderate arthritis.
PRP is rarely covered by insurance, so you’ll usually pay yourself. It’s not a scam, and it’s not a proven fix. Go in with clear expectations.
What PRP is
- Your own blood: a small amount is drawn from your arm, just like a blood test
- Spun down: a machine (a centrifuge) spins the blood to concentrate the platelets, the cells involved in healing
- Injected into the knee: the platelet-rich part is injected into the joint, often as one shot or a course of a few, a week or so apart
- The idea: platelets release growth signals that may calm the joint and ease pain. Whether this changes the arthritis itself is unproven
- No standard recipe: clinics prepare PRP in different ways, with different platelet counts. That’s one reason study results vary
What the trials show
- The biggest placebo trial: 288 people aged 50 and over with knee arthritis had three weekly injections of either PRP or salt water. At one year, pain improved about the SAME in both groups, and cartilage on scans thinned about the same
- Comparisons with other injections: some studies suggest PRP does a little better than gel (hyaluronic acid) or steroid shots over several months. Many of these were smaller or less carefully blinded
- Milder arthritis: results tend to look better in people with early to moderate wear than in “bone on bone” knees
- Safety: because it’s your own blood, serious side effects are uncommon. A few days of soreness and swelling after the shot is typical
Many people do feel better after PRP. The hard part is that many people also feel better after a salt water injection. That’s why the placebo trials matter.
Feeling better after an injection isn’t the same as the injection making you better.
Cost and insurance
- Usually self-paid: few insurance plans pay even part of the cost, and many class it as experimental. The AAOS OrthoInfo page on PRP advises checking with your insurer first
- Prices vary widely between clinics, and a course of several shots multiplies the cost
- Get the total in writing before you start, including any follow-up shots
What has stronger evidence
- Strengthening exercise: recommended for everyone with knee arthritis, at every stage. Thigh and hip strength take load off the joint
- Weight loss, if needed: less weight means less load on the knee with every step
- A steroid shot for a flare: supported for short-term relief, though not as a regular schedule. See cortisone shot in the knee
If you haven’t had a proper go at a strengthening program yet, that’s the place to start. See knee arthritis.
Questions to ask before you pay
- How bad is my arthritis? Results look better in milder knees
- How do you prepare it? Ask about the type of PRP and how many platelets are in each shot
- How many shots, and what’s the total cost?
- What results do you expect, and by when? What happens if it doesn’t help?
- Is it guided by ultrasound? This helps make sure it goes into the joint
- Should I stop anti-inflammatories first? Many clinics ask you to pause them around the injection
- What should I do alongside it? Any good plan still includes exercise
Call your doctor today if
- The knee gets hotter, redder and more swollen after the first couple of days instead of settling
- You have a fever or chills, or feel unwell
- Your calf becomes swollen, warm or painful
Get it checked if
- Soreness after the shot lasts more than about a week
- You’ve had a full course and noticed no change after a few months
- You’re being offered repeat courses without a clear reason
- The knee locks, catches or gives way
PRP might help your knee, but strength and time are the treatments you can count on.