What Is PRP (platlet rich plasma) and Can It Help Your Knees?

Can PRP Help Your Knees?

Platelet rich plasma (PRP) is prepared from the patient’s own blood, which is spun in a centrifuge to obtain a highly concentrated sample of platelets. The platelet solution is used to create a platelet gel, rich in growth factors and bioactive molecules.  These molecules are thought to act to reduce pain and inflammation, and improve function. PRP is a relatively new generation of bioactive treatments and is not yet widely used (and not yet proven).

My Story and Why I Tried PRP

Me, waiting for the centrifuge to do its thing

Two days ago I had PRP (platelet rich plasma) injections in both my knees.  I have bone on bone severe arthritis in my left knee (we'll call that my "bad knee") and arthritic changes involving increased level of pain and discomfort in my right knee (my "good knee").  I've had 8 knee surgeries, (but still have my own knees), and am active and healthy because I ride a bike to stay fit - even with these arthritic knees.  But that doesn't mean I'm pain free.  I've actually qualified for a knee replacement but I'm stubborn and don't want to give up my own bones.

Does the achy grinding pain of arthritis gets the best of you sometimes?  Do you get to a point where you need more relief than ibuprofen has to offer?  Me too.  Cortisone doesn't seem to help me any more,  I had a good experience with viscosupplementation (hyaluronic acid) but my insurance doesn't cover that any more, and so last year I turned to PRP.  In June 2015 I had one shot in each knee and now here it is October 2016, and I've had another injection in each knee.  Oh, by the way, my insurance doesn't cover PRP either and the price tag is pretty steep.  For arthritic knees, my doctor recommended only ONE injection in each knee, not a series as is sometimes done for tendons. In general, injections can cost anywhere from $400 to $1500 or more - but not all injections are the same!  KNOW what concentration your doctor is recommending and why.  Read more about that below.

What is it Like? ...and 2 Days Later

Let's start with the injections themselves and how that works (oh- and remember to bring a cute pair of shorts or you'll end up with the paper ones like I had on).  First, your blood is drawn to create the PRP solution.  Then, about 20 minutes later of processing your blood with a big spin in a centrifuge, the PRP solution is ready.  First the doctor sprayed the injection site with a cold numbing agent to "distract" the nerves.  Then you'll receive a shot of anesthetic which I did not find particularly painful - even though my doctor had to "search" for a path into my bad knee because the arthritic bone spurs blocked the normal route.  Then about 3cc's of PRP is injected into each knee.  After that I rested for 10 minutes with ice on my knees.

[caption id="attachment_314" align="alignright" width="237"] Post injections, ice on knees![/caption]

Immediately, my knees felt "full" and a stiff - but not in the same way as the arthritis-stiff.  The next day I pretty much felt the same with a bit of a slow start when going to walking after sitting for some time.  Today, 2 days later, my knees feel more functionally normal and even pain-free..I'm already happy with the results.  I'm going to get on a bike and take an easy ride into work and see how it feels.  My results may not be typical - it can be weeks before you feel a positive difference and the effect may last up to 6 months or longer.  I actually went 16 months between injections.

By the way, if you are in the Seattle area, I highly recommend Dr. Harmon of UW Sports Medicine Clinic.  She is a family practitioner who works with athletes and has special interest in areas that directly affect her athletes including regenerative medicine (such as PRP), concussions, and sudden cardiac arrest.

Not All PRP is Equal

Dr. Harmon told me that she has options for FIVE different solutions of injectible PRP.  The solution is selected based on the application and requires its own "kit" to create it.  She mentioned that many doctors only order the least expensive kit and offer just one type of PRP solution - which may not be the best application for you.  Be sure to ask your doctor about this!

Want More Science of PRP?  PRP Explained.

This is fascinating stuff!  PRP classifications* have been created based on two key parameters:  presence of white blood cells (leukocytes) and fibrin (a protein responsible for blood clotting by creating a "mesh").  With these parameters, four main families of PRP were distinguished.  Liquids can be injected, gels cannot:  the more fibrin included in the solution, the thicker, or more viscous, it gets.

1. Pure Platelet-Rich Plasma (P-PRP) has a low to no white blood cell count and low levels of fibrin. (Liquid or Gel).
2. Leukocyte and Platelet Rich Plasma (L-PRP) includes white blood cells and low levels of fibrin. (Liquid or Gel).
3. Pure Platlet-Rich Fibrin (P-PRF) has no white blood cells and a high level of fibrin.  (Gel form only).
4. Leukocyte and Platelet Rich Fibrin (L-PRF) with white blood cells and high level of fibrin. (Gel form only)

Within this classification there are many different options to create the ratio of platlets, white blood cells, and fibrin.  Ask your doctor what they use and why!

*Source:  Ehrenfest, D., Andia, I., Zumstein, M., Zhang, C., Pinto, N., & Bielecki, T., (2014, May 8) Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine:  current consensus, clinical implications and perspectives. Muscle, Ligaments and Tendons Journal 4(1): 3-9 retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049647/