The use of PRP for “regenerative” purposes has been well documented elsewhere for as diverse purposes as cosmesis, hair growth, tendinopathy, heart disease and many other health problems. Scientific evidence in well controlled studies for improved outcomes has yet to be produced for most of these issues. One area in which we will soon seen some early outcome studies is the use of PRP for osteoarthritis, an indication that I have been exploring for about two years.
When investigating a disease as manifold as osteoarthritis (OA), it is important to set the ground rules appropriately. First, the patients need to have IMO mild or moderate disease, not the end stage bone-on bone disease with associated abnormalities- like crookedness and looseness- that cannot reasonably be expected to be helped by injections. If you include these severe cases in a sample, it is a guarantee the results will not be comforting. The film on the right is still acceptable for PRP treatment.
Second, one has to spend time on investigating the precise PRP that is being used- how concentrated is the product- and this varies widely depending upon the manufacturer. To some extent, it may also vary according to the patient’s native platelet count- more on this later. Once we know the dose per injection, then we have to determine the right dosing schedule- how many injections? In other words, if PRP is to be accepted in the long term, we need to establish a dose-response relationship, as with pharmaceuticals.
Finally, it would helpful to compare PRP with other available injectables. Even though commonly used, I will rule out cortisone as a comparator because of the obvious side effect upon cartilage. Patient’s experience excellent short term results with cortisone injection, but I have seen some of the worst cartilage damage in those joints subject to repeat injections. I seldom recommend cortisone for that reason.
A reasonable comparator would be hyaluronic acid (HA), now available under many brand names for injection (and also used for cosmetic injections, and for eye surgery). I have about 10 years experience with HA, and it is effective in pain relief for OA in about 2/3 of patients who try it. The effect can be months or even longer. HA is composed of large, viscous molecules and does not contain growth factors.
A study comparing HA to PRP for OA of the knee is being performed at Rush Medical at the present time, and we eagerly await the results. Early indications appear favorable for PRP, but this study has not yet been published in a reviewed journal. A similar study performed in Italy has shown excellent medium term results with PRP.
In my opinion, high concentrates (12-14x) of PRP are effective for pain relief due to OA if given to appropriately selected patients. The regimen requires (2) injections over a 2-3 week period. The response rate is approximately 85%, a definite improvement over HA. The duration of symptom relief is variable, but appears to be in the 6-12 month range.
I look forward to learning more about PRP in 2012 as new studies become available and better analytics allow us to better quantify precisely the dose we are administering.