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Injecting platelet-rich plasma into a joint or tendon leads to the release of growth factors improving the local environment.

Platelet-rich plasma injections for joints and tendons are becoming more popular. They form part of the new field of regenerative medicine for use in joints and tendons to reduce pain and encourage healing. But is there evidence that a platelet-rich plasma injection works for conditions such as arthritis and tendonitis?

What is platelet-rich plasma?

Platelet-rich plasma or PRP comes from whole blood. We obtain blood from a vein in the patient’s arm. The spinning of the blood forms different layers: red cells, white cells, and plasma.

The plasma component, which contains high levels of platelets. is separated and injected into joints or tendons. Red and white cells are removed. Generally, injections are performed with ultrasound to ensure accurate targeting of the desired joint or tendon.

How do platelet-rich plasma injections reduce pain?

We don’t know the answer yet. However, there are many studies analyzing the effects of PRP on cells and tissue in a lab. Platelets are important cells that control clotting. They contain a high concentration of growth factors.

These growth factors control inflammation and healing. Injecting platelet-rich plasma into a joint or tendon leads to the release of growth factors improving the local environment. Ultimately, this leads to a lower level of pain and tissue healing.

Researches prove that PRP reduces pain and potentially delays the need for a knee replacement.

Do platelet-rich plasma injections regenerate cartilage or tendon tissue?

We don’t think so. There is no evidence that any injection is able to regenerate tissue. However, there are ongoing studies looking at this question. Ultimately, the pain-killing effects of PRP are due to a better environment of the joint or tendon rather than tissue regeneration.

Is there evidence for platelet-rich plasma injections?

Yes, but strong evidence exists for only a few common arthritis and tendonitis problems:

  1. There are now 21 randomized controlled trials that show PRP is better than other injections (such as cortisone or hyaluronic acid) for improving pain in knee osteoarthritis. PRP has shown better results than hyaluronic acid for knee osteoarthritis.
  2. PRP is better than cortisone for tennis elbow in some studies.
  3. In plantar fasciitis, PRP is better than cortisone in 9 studies. In patients with severe plantar fasciitis, PRP is better than cortisone and safer than surgery.
  4. One study shows that PRP is better than cortisone for hip tendonitis.

However, platelet-rich plasma has not shown effectiveness for other joints and tendons such as the hip joint, ankle joint, Achilles tendon, or shoulder tendon.

You can read about the other effective treatments for arthritis, and other injections for arthritis.

How many platelet-rich plasma injections do you need?

We think that 2-3 injections every 2 weeks are required for knee osteoarthritis. For tendons, we recommend one to two injections two weeks apart.

Will platelet-rich plasma injections hurt?

Generally no. Sometimes, the doctor will inject a local anesthetic into the skin to stop the PRP injection from hurting. Also, PRP injection should be done with ultrasound meaning the injections hurt less. Usually, a few people require pain killers after a PRP injection. Overall, we recommend you take paracetamol after injection if needed.

What are the potential side effects of PRP injections?

Generally, PRP injections are safe. However, patients can be sore in the joint or tendon for up to a week. Also, the positive effects do not start for at least 2-3 weeks after injection. Overall, the risk of infection is lower than other injections.

How long should you rest after PRP injections?

Normally, it depends on whether a joint or tendon is injected. For arthritis, we suggest resting from running or sport for a few days. For tendons, we recommend a slightly longer period of time of up to a week.

What about combined injections: PRP and hyaluronic acid?

Hyaluronic acid is a natural substance found in cartilage, joints, and bone. Hyaluronic acid injections are used for knee arthritis and have shown promise like PRP. However, recent studies using PRP and hyaluronic acid combined have shown even greater promise.

Be sure to get in touch with a team of our qualified experts if you need a free consultation.