Achilles tendon tears are devastating injuries that lead to significant pain and disability. Previously, most people ended up with surgery but over the last few years, many studies have come out suggesting that a lot of people can actually do very well with non operative management. And if these people can be treated nonsurgically, can we then use platelet rich plasma to improve the healing process and augment healing? That’s what this randomized controlled trial tried to answer. The authors recently published their 2 year follow up results.
Achilles tendon ruptures lead to significant limitations to work and sporting activities. And because of this, we are always looking for new treatments that can help facilitate healing and improve recovery times. One of these potential options is platelet rich plasma.
PRP has been shown to be beneficial in overuse and repetitive stress injuries such as tennis elbow, golfer’s elbow, gluteal tendinopathy, and plantar fasciitis. But less is known about using PRP in acute injuries such as achilles tendon ruptures. Can we use PRP to increase the speed of healing in achilles tendon tears? That’s what this study tried to answer. This was a randomized controlled trial comparing PRP injection to placebo injection for acute achilles tendon ruptures. They wanted to know if adding PRP to nonsurgical treatment would improve patient reported function and quality of life. The study had a total of 230 participants, 114 in the PRP group and 116 in the placebo group.
The study used Magellan PRP kits which involved a 50 cc blood draw to produce a final volume of 8 cc’s of PRP. The authors then decided to take 4 cc of their PRP for lab analysis and to inject the other 4 cc’s into the tendon rupture. The authors report that their PRP had a 4.1 fold greater platelet concentration than baseline. This would have resulted in a total of around 4-5 billion platelets. No activating agents were used.
Now how did they deliver their PRP injections? This is something that is not talked about enough. The authors report that ultrasound guided injections were NOT done and that the treating healthcare provider palpated for the defect in the tendon and injected the PRP without imaging guidance. Physicians in training delivered the injections in 25% of subjects. All participants then underwent standard non surgical management for achilles tendon ruptures under the supervision of a physical therapist.
So what did the authors find? At two years of follow up, the authors write that “there was no evidence of a difference in the achilles tendon rupture score or other secondary outcomes, and there were no re-ruptures between 24 weeks and two years.” The authors go on to conclude that PRP injection did not improve patient reported function or quality of life two years after acute achilles tendon rupture compared with placebo.
Ok so does this study mean we should not be using PRP injections to treat problems involving the achilles tendon? Well it really does seem like the medical literature is moving that way. This study adds to the growing body of evidence that PRP injections may not be useful in the treatment of acute achilles tendon ruptures as well as chronic achilles tendonitis and achilles tendinopathy.
But for fun, let’s take the counterargument side. What are some critiques of this study? The first is platelet counts. There are some studies that argue platelet counts are critically important to the success of platelet rich plasma injections. They argue that when you conduct a PRP study and conclude there was no benefit, is it because there truly is no benefit or is it because you just didn’t administer enough platelets? Said in another way, did you just underdose your treatment?
So this study started off with a PRP kit that would have isolated between 8 to 10 billion platelets. That actually seems to be the goal range for PRP injections. But the authors decided to take HALF of those platelets for laboratory analysis and inject the other HALF as treatment. So critics of this paper would then argue, well you got rid of half of your platelets, of course you didn’t get a result showing benefits to outcomes. You underdosed your treatment. We know insufficient platelet count was a big problem with the RESTORE trial for knee osteoarthritis.
So I actually brought this up with one of the authors on Twitter. And this was his response, “absolute [platelet] number is never critical. The concentration may be, but there was no link with this either.” I respectfully disagree here. Lots of newer studies like this one suggest platelet number is critical. But this is newer information that was not available when the authors first designed the study.
Another critique of the paper is the method of injection. Many providers doing orthobiologic and cellular therapy argue that all injections must be done with imaging guidance. Otherwise, you have no idea if you administered the PRP in the correct spot. And if you don’t get the PRP in the right spot, how can you expect benefits to outcomes? There are now numerous studies all concluding that ultrasound guided injections are superior to landmark and palpation based injections. Of course this makes intuitive sense, but we still need to see the data.
And that’s what this study did. The authors aggregated existing evidence on ultrasound guided injections using data from cohort studies as well as randomized controlled trials. I compiled the results into this chart and you can see there is a striking difference between injections done ultrasound guided when compared to landmark based injections.
Ultrasound guided injections are between 90 and 100% accurate for every body part. Landmark based accuracy ranges in the mid teens to the mid seventies for most indications. There’s no way to sugar coat this, that’s pretty bad. No other medical specialty would accept outcomes like these.
Ultrasounds are becoming much cheaper. There really is no excuse to do injections quote and quote blind, especially in clinical trials where the outcomes and conclusions really can shape how physicians practice. So when I see a study done without imaging guided injections, I really need to ask the question, are the results valid or is it that their injections missed? Without imaging guidance, I really don’t know.
Okay so with all that said, how does this study change my practice? Well, I think the medical literature is pretty clear that PRP does NOT help improve healing in achilles tendon injuries. That includes acute tears as well as chronic achilles tendinopathy.
This study is a systematic review and meta-analysis looking at the use of PRP for chronic midsubstance achilles tendinopathy. Their results showed that “there was no difference in clinical outcome between the PRP and placebo group at different points in time using the VISA-A score as outcome parameters at 3 months, 6 months, or 12 months.” The authors in that study went on to conclude that PRP has no clear additional value in the management of chronic midsubstance Achilles tendinopathy and therefore should not be used as a first-line treatment option.”
I’ve actually stopped recommending PRP injections for achilles tendon injuries unless someone really is adamant about trying everything possible before surgery. And even then, I’ll counsel these patients that PRP may not help.
I think the more important thing to take away from this study is the method by which studies are done and what to look for when reviewing clinical trials. What kind of PRP is the study using? How many platelets are being injected? How are the PRP injections delivered? Are they done landmark based or ultrasound guided? All of these will affect outcomes and are things that you should be asking your healthcare provider about if you are interested in getting a PRP injection.