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by Danielle Fox, DPT

In the last few years, PRP injections have been in the headlines as a new injection used by professional athletes and weekend warriors alike to improve healing after injury. What are these injections and do they really work?

PRP injections have been around since the mid 1990’s when surgeons began to use this injection for bone healing following spine surgery and tissue healing following plastic surgery. Now many athletes and orthopedic patients are inquiring about these injections to assist in healing following surgery to many joints such as the ankle and knee as well as conditions such as Achilles tendonitis and patellar tendonitis. Tiger Woods and Hines Ward have made headlines for utilizing such injections before winning important matches and games.

PRP stands for platelet rich plasma. It is obtained from the patient by drawing about 30 milliliters of blood and putting it through a centrifuge to separate out the different components of blood. The plasma is then injected back into the patient directly to the area of injury.

How does this help heal the injury? Many types of conditions where a PRP injection would be used are a chronic overuse injury such as Achilles tendonitis or patellar tendonitis. With these types of injuries there are often microscopic tears in the tendon, but these tissues don’t have a great blood supply making it difficult for oxygen and nutrients to reach the tendon. The PRP injection will stimulate growth and healing to the tendon/tissue injured. The platelet rich plasma naturally contains the body’s own growth factors and nutrients to give a “healing boost” to the area.

What is the dose and how often are the injections given? Right now there is no rubric for how much PRP to inject or how often. Some patients are injected once while others are given two to three injections over the span of several weeks. This can depend on area of injury as well as nature of injury. The 30 milliliters of blood drawn gives the centrifuge enough to work with to separate out the plasma, only the plasma is injected back into the body.

Do studies prove this works? I feel this question is the trickiest question in terms of “evidence based practice”. It is very difficult to perform random, blind, placebo effect compared trials. In trials performed so far the model has been to take a sample of people with a certain injury such as Achilles tendonitis and provide them with PRP injection to assess for progress. These studies have shown good evidence to support the injections. Personally, I believe healing in the human body is never due to just one factor. If something like PRP can be added to other treatments in assisting a patient to heal, and the patient does heal more efficiently and effectively then it is a valid treatment option.

One downside to these injections is that almost no insurance company is going to pay for these injections. This is due in part to the lack of “random clinical trials with placebo comparison”.

To sum it all up, these injections are safe when administered appropriately with very few side effects. If the injection doesn’t help, it won’t hurt either. It may be a good topic for discussion with your doctor to see if these injections would be a viable treatment option for you.

Dr. Fox is a Physical Therapist at Boston Sports Medicine