Platelet-rich plasma (PRP) injection is a biologic therapy that can stimulate healing and enhance repair in certain injuries. PRP often is referred to as an orthobiologic, since it is obtained from a patient’s own blood and centrifuged to increase the concentration of platelets to treat orthopaedic injuries and conditions. PRP injection may be a good alternative treatment in the management of tendon, ligament, muscle, and/or cartilage injury.

A PRP treatment is a relatively simple process: The doctor will draw blood then use a centrifuge to produce PRP. PRP contains a mixture of concentrated platelets, including cytokines and growth factors, and has anti-inflammatory properties. The PRP is injected into an injury site to stimulate the healing process. It can also be injected during a surgical process to augment healing and speed recovery.

PRP has been used for years to treat professional athletes and is now increasingly used to help active adolescents and adults with sports and other orthopaedic injuries.

Blood is made up of four primary components: Plasma, red blood cells, white blood cells, and platelets. Plasma is the liquid component of blood—about 90% of it is water. Red blood cells transport oxygen, and white blood cells help the body respond to infections and injuries. Platelets are tiny cell fragments that circulate in the blood and play a central role in blood clotting. They can also be thought of as one of the first responders to an injury. When they arrive at the site of an injury, the platelets become activated and release growth factors and proteins called cytokines that promote the healing of injured tissues.

PRP is a therapy produced from the patient’s own blood that is made up of plasma and a high concentration of platelets. It is injected into the injured area, thereby introducing a high concentration of platelets (as well as growth factors and cytokines) to the injury site, helping it heal.

To make PRP, the doctor will first draw your blood, then put it in a centrifuge, a device that spins at high speeds. The centrifuge separates red blood cells from the plasma and platelets.

After discarding the red blood cells, what remains is a mixture of plasma and a concentration platelets. PRP typically contains three to five times the number of platelets found in the blood that is circulating in your body. PRP also contains white blood cells (also known as leukocytes). When PRP is prepared so that it has a higher-than-normal level of leukocytes, it is called leukocyte-rich PRP. When it is prepared so that it has a lower-than-normal level of leukocytes, it is called leukocyte-poor PRP.

Platelet-rich plasma injections can be used to treat such degenerative conditions as osteoarthritis, as well as tendon, ligament, and muscle injuries. At Yale Medicine, orthopaedic surgeons, sports medicine specialists, and physiatrists use PRP injections to treat people of all ages.

Some of the specific conditions that doctors use PRP injections to treat—or use as a supplement to another treatment, such as physical therapy—include the following:

• Neck and back pain
• Chronic ligament or tendon injuries
• Golfer’s elbow and tennis elbow
• Osteoarthritis of the hip, knee, or shoulder joints
• Rotator cuff injuries
• Injuries of the cartilage, ligaments and tendons

PRP can also be used in conjunction with surgery to enhance healing and recovery.

PRP can be administered in the doctor’s office. The doctor will draw your blood, spin it in the centrifuge to prepare the PRP, then inject the PRP directly into the site of your injury. The injection may be done with ultrasound guidance. The entire process should take less than an hour. You may need to rest following the procedure.

It’s important to follow the doctor’s instructions on how quickly to return to sports or other activities to ensure optimal recovery. Because nonsteroidal anti-inflammatory medications (NSAIDs), such as ibuprofen, naproxen, and aspirin, can impair platelet function, you may be advised to stop taking them for two weeks in advance of a PRP treatment.

You may need to come back for additional PRP treatments, or your doctor may provide PRP in conjunction with other treatments, such as physical therapy or other medications.

Every patient is different, but doctors believe PRP may promote a longer-lasting recovery from an injury than some other treatments. Some patients report that their pain improved in four to six weeks—sometimes sooner—and that their condition continued to show improvement for up to a year.

It’s worth noting that particular PRP treatments will have varying levels of success with different patients, and doctors are still researching why this may occur.

Platelet-rich plasma injections are minimally invasive and rarely causes side effects. Because it comes entirely from a patient’s own body, there is no concern about rejection or disease transmission. The most common side effects from PRP injection are discomfort, pain, and/or stiffness at the injection site.

You may not be a candidate for PRP injections if you have certain conditions, including:

• Blood dyscrasia (a disease or disorder of the blood)
• Thrombocytopenia
• Sepsis
• Anemia
• Cancer

This article was medically reviewed by Yale Medicine orthopaedic surgeon Arianna Gianakos, DO.