New JAMA article on Achilles Tendon injury promotes dialogue on PRP
In a recent article in the Journal of American Medicine (JAMA), a group from the Netherlands studies PRP VS saline injections under ultrasound guidance. The patients were studied for 6 months as a preliminary report. The study showed that both groups equally improved beyond baseline. The researchers concluded that the injection was no more than a placebo effect and that the eccentric exercises that both groups performed may have caused the benefits.
It’s great that more & more evidence is emerging on PRP therapy. This study was a single center randomized blinded trial however it did have some limitations.
Here are my thoughts.
My published review article is referenced in the JAMA article. While the authors of this study should be commended by adding to a topic in need of controlled trials; there are some limitations to be mindful of before drawing indefinite conclusions.
First, there was no gel matrix added which may have limited the duration of time the PRP was in the tendon. The injection graft was activated by direct contact with the tendon upon injection without an agonist. I currently use a PRP that utilizes a gel matrix by utilizing autologous thrombin combined with calcium chloride.
Secondly there were no laboratory platelet counts performed to determine what PRP levels were achieved. There are numerous platelet separation devices available with varying concentrations of platelets & leukocytes & having definitive counts would have been insightful.
The authors unfortunately did not have a third control group to isolate the effects of an eccentric exercise program. It is unreasonable to assume that the eccentric exercises alone accounted for the substantial clinical improvement of VISA-A & satisfaction surveys in both groups. Moreover there is no discussion on the theory that the ultrasound guided needle procedure in both groups may have created microtrauma that could initiate healing.
Also there is no long term f/u beyond 6 months. Follow up in 12 months may indicate a difference between the two control groups. Also there is no follow up imaging to determine if there is structural healing occurring.
The article provides good follow up data on a single injection, however for chronic Achilles tendinosis, a series of injections may be required.
It’s terrific that more & more studies are emerging to better define how PRP is best indicated. In my experience chronic Achilles tendinosis is a very challenging condition with limited treatment options. This study suggests that needling of the injured tendon under ultrasound guidance combined with an eccentric exercise program was effective initially for 6 months. However long term follow up data & imaging is necessary to clarify interpretations. As with any treatment there will be pro & con articles. In the end we’ll continue better understand this treatment which is in no way a panacea.
Dr Steven Sampson
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