September 01, 2020

Is a platelet-rich plasma injection a safe and effective option for knee arthritis?

Q: I have had knee pain related to osteoarthritis in my knee for a long time, and all the treatments I've tried haven't helped enough. One of my friends recently had platelet-rich plasma injections for his osteoarthritis pain. Is this a reasonably safe and effective option?

A: It's true that platelet-rich plasma (PRP) injections are sometimes used to treat osteoarthritis, a frequently painful condition that develops when the protective cartilage that cushions the ends of your bones deteriorates over time. Additionally, PRP has been used to treat ongoing (chronic) soft tissue injuries such as plantar fasciitis and tennis elbow (lateral epicondylitis).

When you are injured, platelets travel to the damaged area where they form a clot to help prevent excess bleeding. Platelets also deliver many proteins and other molecules that attract other cells — such as stem cells — to the area. With some conditions, these cells and proteins may aid healing, while with others they may provide just pain relief.

The goal of PRP therapy is to harness the healing power of platelets. It's a type of regenerative medicine, which aims to use the body's ability to heal itself.

To prepare a PRP injection, your blood is drawn — Mayo Clinic experts draw about 6 ounces at most — and put into a centrifuge, which spins the blood to separate the platelets from other blood cells. The colorless, fluid part of the blood (plasma) that's rich in platelets is then injected into the injured area in need of healing.

Research on PRP treatments is ongoing and evidence varies depending on the condition treated. PRP has not been shown to regenerate or heal the damage in a joint with osteoarthritis. However, many PRP studies have demonstrated pain relief and better joint function with osteoarthritis, likely through reduced inflammation.

Studies of PRP in the...