Arthroscopy Journal Podcast – Dr. Tucker & Dr. Ranawat discuss “Arthroscopic Treatment of Femoral Acetabular Impingement in Adolescents Provides Clinically Significant Outcome Improvement”
Welcome: Welcome to the Arthroscopy Association's Arthroscopy Journal Podcast. The views expressed in this podcast do not necessarily represent the views of the Arthroscopy Association or the Arthroscopy Journal.
Dr. Tucker: Welcome everyone! I'm Dr. Chris Tucker from the Walter Reed National Military Medical Center in Bethesda, Maryland, and co-founder of this podcast. Today I have the privilege of speaking with Dr. Anil Ranawat, the sports medicine fellowship director at the Hospital for Special Surgery in New York City.
Dr. Ranawat was the senior author on a paper titled “Arthroscopic Treatment of Femoral Acetabular Impingement in Adolescents Provides Clinically Significant Outcome Improvement," which was published in October 2017 in the Arthroscopy Journal. His co-authors include Drs. Nwachukwu, Chang, Kahlenberg, Fields, Nawabi, and Kelly. Welcome, Anil, and thanks for joining me.
Dr. Ranawat: Thank you, Chris.
Dr. Tucker: Now, what can you tell us about your study, right out of the gate, that's going to make me sit up and take notice?
Dr. Ranawat: I think this is an important study because it's changing the landscape of how we critically analyze our sports medicine research. There's a lot of interest or people almost criticizing the use of strict P-values to judge clinical improvements after a surgical procedure, per se, or any intervention. There's even a direct quote from a leading statistician saying "The P-value was never designed to just show statistical significance to verify whether a procedure was effective or not."
Based off that concept, we looked at this concept called MCID or Minimal Clinically Important Difference. But what I really define MCID is when you have a change from a pre-operative to post-operative PROMs data, or any sort of objective assessment tool, the MCID defines what I would call the floor, or minimal threshold effect.
The minimal threshold effect is showing from the patient's perspective what they really think is the minimal difference, which is usually greater than the P-value, to show that they're actually happy with that procedure. This is in stark contrast to what we traditionally found what just P-values are. Because sometimes, the P-values can show a difference, but with large error margins, which really, from a statistical point of view, and from the patient point of view, is not really valid, and the patient doesn't actually feel any minimal clinically important difference.
Meaning, that they don't find any difference in how they felt before or after their therapeutic intervention, which is, I think, a groundbreaking change of how we critically analyze our procedures, whether it's a meniscal allograft, hip arthroscopy, or even using rehab or PRP.
The second concept is using this interesting statistical concept of substantial clinical benefit. If you think of MCID as the floor or the minimal threshold, the SCB is the upper threshold for clinical success. And this is usually based on one clinical question. It's the most simple question you ask a patient. "Are you happy with the surgical procedure?" And if they say, "Yes,” then that is what a year later defines the threshold, or the ceiling effect of would they do the operation almost again.
Using these two concepts, minimal clinical important difference on the bottom or our floor and SCB as our threshold or ceiling effect, that is a new way how we can really critically analyze our therapeutic interventions.
Dr. Tucker: Yeah, I agree with you. I think that this is some ground-breaking information for those of us measuring outcomes in our procedures. It was interesting to me to see how you compared your current study’s findings to those from a previous report where you measured outcomes in adults. In your conclusions on this study you stated that although adolescents readily achieve minimal clinically important differences, a considerable improvement in post-operative outcome scores is often needed to perceive a substantial benefit. Can you explain what exactly you mean by this?
Dr. Ranawat: Yeah, sure. To go back to the concept of the floor and the ceiling effect, we found that 92% of adolescents had a minimally clinical important difference. A large percentage got to the ceiling effect - the MCID. And that we always think is based on these people are healthier, they're more active, and they have very, very low arthritic indices.
When we compare that to our adult population, that number was higher for the adolescent or lower for the adult. Likewise, what we also found interesting in terms of the ceiling effect or the SCB, we found the opposite. The requirement for an adolescent to get to a ceiling effect had to be a higher number than in the adult population, which means that our adult patients are happier with lower functions, but our adolescent populations, because they're more active and they're probably playing more sports, more activities, want more function. They want even better results.
So that gauges you to the point that to do an intervention on the younger person, they really need to get a great outcome. And to do an intervention on an older person, a good outcome from a patient perspective, which really is what this is all talking about, is almost good enough. Now that could be one theory. The other theory could be just our instruments to critically analyze these differences may not be accurate. Meaning our iHOT or any of our outcome data may have a ceiling effect in its own right. Meaning that for the adolescents, they want to have so much more defined function, we don't have maybe the most accurate tool or instrument to really have an adolescent specific functional score to really sub-stratify that top area.
But it is interesting that for an adolescent to be happy with the procedure, to get an SCB, they need to have a lot of functional improvement, which also makes you think your indications for a procedure for an adolescent versus an adult may vary based off that understanding.
Dr. Tucker: I think you highlighted a really important point there regarding the tools we're using to measure our outcomes. Your study highlights the difference between what's statistically significant and what's clinically significant with regards to outcome measures for orthopedic procedures in general. Do you think as a profession we're heading in the right direction with regards to how we're measuring how well our patients are doing?
Dr. Ranawat: Yeah, I mean, I think we've seen a major revolution in how we're looking at statistical models and level of evidence that's finally really being entered into orthopedic care. Originally you had concepts of poor to bad results, moderate results, and good to excellent. Then we evolved into P-values.
You're saying, "Okay, let's use an outcome measure and let's say the Harris hip score and let's see a P-value difference." But again, a lot of those instruments were surgeon derived, not patient derived. So then when we had patient reported outcomes, which we're doing a lot more, and now we have MCID and SCB. And I really think MCID and SCB is becoming now the standard of care of how you analyze any therapeutic intervention and even by the time from this paper had been published, which was about a year ago, if you look at the level of penetration of MCID and SCB in our literature, I would say it is a 15 to 30% increase every year.
Just how we now have to put a level of evidence in every paper, and every paper then needed a P-value. I would say in the next five years every paper that uses outcomes data will have to have MCID and SCB reported.
Dr. Tucker: I think that's fantastic. I think your work supports this trend in a really significant way. To jump off the topic of statistics for a moment, there's been a number of studies showing that sports participation during skeletal maturation leads to a higher risk of developing FAI. In light of your findings from this study that show corrective arthroscopic surgery can lead to significant improvement in adolescents, do you think we should encourage more proactive hip screening for adolescent athletes or maybe even just image everybody in the pre-season and scope them in the off-season?
Dr. Ranawat: I mean, I think the data here is showing how we can help a select group of individuals. I do think that sports participation at a young age is a great thing. I think over sports specialization is a bad thing. Just if you have a throwing shoulder and you throw 12 months out of the year, we all know that's bad for you. And if you have a developing hip and you're playing one sport, whether you're saying you’re a soccer player or a butterfly goalie, that's bad for the hip as well.
So over sports specialization can, I think, negatively re-model a hip and create more impingement. I don't believe in x-ray screening for every adolescent athlete, but I do think scoliosis screening is a very simple and benign thing to do. And I think hip internal rotation is a very easy and benign thing to do. And that's something that I think you'll see more and more ... you're seeing in the Scandinavian countries where hip impingement is very prevalent and we're going to see it more and more in our population.
It's something that any trainer or physical therapist could do. You don't need a physician to do that. And if you find an individual with zero or very, very low internal rotation, that can offer a screen no different than how we do pre-physical assessments for some cardiac function tests. That's something I think that will become more and more popular in the future, but I don't think you need to have x-rays on every kid.
Dr. Tucker: Thank you so much for sharing your thoughts with us today, Dr. Ranawat. Dr. Ranawat's article titled “Arthroscopic Treatment of Femoral Acetabular Impingement in Adolescents Provides Clinically Significant Outcome Improvement” can be found in the October 2017 issue of the Arthroscopy Journal or online at www.arthroscopyjournal.org. Thank you for joining us.