Good afternoon, I'd like to thank you all for the opportunity to speak with you today on behalf of my co-authors. It's a privilege to be here and we have no disclosures except that I am a general surgeon so take that for what it's worth. So just a little background on this. This observation goes back about a decade where in our clinical practice we started to observe what we thought to be an uptick in the amount of heterotopic ossification we saw in patients presenting with core muscle injuries in our practice. So this is a single institution observation where we have a unique practice where really all we treat are core muscle injuries and we define that as injuries in the skeletal muscles from the chest to mid-thigh and usually the surgical ones are those involving the rectus abdominis and adductors where they attach to the pubic bone, often referred to as a sports hernia. And so that's really the focus of our practice and so it gives us a unique opportunity to make observations about these injuries. And so in 2018 at the annual meeting I presented our initial observations just based on a relatively small group of athletes focusing primarily on NFL athletes because that's where we made this observation and also where we saw PRP being more widespread than the general population at least in the earlier part of 10 years ago. And so at that time we saw four out of five NFL athletes with prior PRP injections had HO at the time of surgical repair of their core muscle injuries. And then we looked at all of our patients during that same time period and found 15 other patients who had prior PRP injections and 13 of them had HO. And then when we looked at kind of all the other athletes and patients that we treated we saw a much smaller incidence of HO among that population. So our goal for this study was just to expand the scope and just look at a larger group of patients. So we basically started identifying people in 2014 via specific questionnaires had they had any prior PRP exposure. And then we, for the purposes of this study, defined HO as a pathologic definition. Certainly it can be seen on x-ray and ultrasound and also sometimes on exam, but we used pathologic definition. So that means if we didn't get a pathologic specimen we were not able to diagnose them as having HO. We also excluded intra-articular injections of PRP thinking that that would have less systemic effects. So for this study we were able to look at over 3,600 new patients with suspected core muscle injuries. And so of those 3,600, only 68 developed HO, which is less than 2%. But of those 68 athletes, 44 of them had prior PRP treatments. Similarly when we looked back at the patients who had prior PRP exposure, it was about 108, about 3%. And of those 108, 99 underwent surgery and 43 of those 99 had HO pathologically. Of the remainder of the patients we identified HO in 24 of those patients, which is a much smaller incidence. So then we went back to NFL athletes because that's a nice population for us to study. We tend to get good follow-up and they're obviously highly motivated for the most part to get back to play. And so again we had 28 NFL athletes who had developed HO in our practice. So then we tried to match them with 28 other NFL players. We matched them by age, position, location, and severity of their injuries. And so in that PRP group that developed HO, 22 out of the 28 athletes that were NFL athletes developed HO, whereas none of the NFL athletes with no prior PRP exposure had HO. And the thing that was significant here that I think is relevant is that we historically have seen about a 95% success rate getting our athletes back to pre-injury level of performance, which is how we define success. And we certainly saw at the three-month post-op a difference between these groups. Those NFL athletes who had developed HO and had prior PRP seemed to have a slower recovery afterwards. And this difference went away after six months and a year. So this is a very limited study. It's a single arm and we're just really assessing the patients that come to our clinic. So we're looking at failed PRP treatments. That's an important note. I think what this does highlight though is that HO is a potential complication of the use of PRP for core muscle injuries and it perhaps is associated with the delay in recovery from the eventual surgery. Certainly I hope this just simulates interest and continued observations and certainly something prospective would be great to help us identify actually what we can expect in terms of a true incidence. Thank you for your time.

general surgeon

heterotopic ossification

core muscle injuries

NFL athletes

platelet-rich plasma