In this installment of the Off the Field series, host Melissa Deuber connects with Dr. Jed Diekfuss, an assistant professor at Emory and lead researcher at the Emory Sports Performance and Research Center (Emory SPARC). This episode dives into the biological complexities of recovering from an ACL reconstruction. Dr. Diekfuss discusses a groundbreaking study that utilizes advanced knee MRI technology to track how a quadriceps tendon autograft evolves into a functional ligament, a process known as ligamentization.
Article discussed in the show:
Smith, D. R., Anderson, K. D., Champagne, A. A., Warren, S. M., Zuleger, T. M., Slutsky-Ganesh, A. B., Hsiao, H. I., Lamplot, J. D., Slone, H. S., Xerogeanes, J. W., Myer, G. D., & Diekfuss, J. A. (2026). Twelve-Month Maturation Timeline of Quadriceps Tendon Autograft Signal Intensity Ratio After ACL Reconstruction Surgery Using Magnetic Resonance Imaging. Orthopaedic journal of sports medicine, 14(1), 23259671251397650. https://doi.org/10.1177/23259671251397650
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Melissa: Welcome to Behind the Breakthroughs. I'm Melissa Deuber from the Woodruff Health Sciences Center Library. In each edition, we take a closer look at the research shaping health, healing, and human performance at Emory. Today’s episode is part of the Off the Field series, where we explore how science moves from the lab to everyday life. I’m joined by Dr. Jed Diekfuss to talk about their work, the questions that drive it, and what can make it possible.
Let's get started. So, tell me a little bit about yourself and how you started to do the work that you do.
Dr. Diekfuss: Hi Melissa, well thanks for having me. So, I did my PhD at the University of North Carolina Greensboro, where I was interested in motor control and motor learning. Specifically, I was interested in how the brain changes in response to practice and experience. So, how do you learn to kick a soccer ball, how do you learn to throw a football? And to do that, I developed skills utilizing something called MRI, or magnetic resonance imaging. And then throughout my PhD, that has translated to applying those skills to areas in my postdoc and eventually where I am now, where we're looking at changes in the brain in response to concussion, injury prevention, injury rehabilitation.
So now, I'm an assistant professor here at Emory, and I oversee all the MRI-related research activities at what's called the Emory Sports Performance and Research Center, or Emory SPARC. And I'm excited to talk today about one of our studies that was led by one of our postdocs, Dr. Daniel Smith, and give you a summary of what that study was all about.
Melissa: So, for this particular study, what question were you trying to answer when you started it?
Dr. Diekfuss: Yeah. So, when we started the study, the main question was: how does a quadriceps tendon ACL graft change during the first year after surgery? We know that ACL grafts go through a biologic healing process, often called ligamentization. But there's been much less data on the quadriceps tendon graft specifically.
So, we used knee MRI to track the graft at three, six, and twelve months after reconstruction and compared it with the patient's native ACL on the opposite, uninjured knee. The ultimate goal is to better understand the timeline of healing, because this has implications for the risk of re-injury, how the athlete recovers, and if they will do well and perform well when they return to sport.
Melissa: So, that is very interesting stuff, but if you had to explain what this study is really about to a friend or family member who maybe doesn't work in science or the medical field, what would you say?
Dr. Diekfuss: That is a great question. So, I’d say the study is about understanding when a reconstructed ACL starts to look and behave more like a real ligament again. So, when you get an ACL reconstruction surgery, the surgeon will take part of a tendon—and in this case, it was the quadriceps tendon, which is right above the knee joint—and use that tendon to replace the ligament.
But that tendon doesn't instantly become an ACL; it must go through a healing and remodeling process over time. So, what we did was use MRI to watch this process happen after the first year after surgery. And what we found was that the graft still looked different from the native ACL at three and six months, but by twelve months, or about a year, it looked much closer. And we also found that different parts of the graft healed at different rates, providing some insight into the recovery and the maturation process across the entire structure of the new graft.
Melissa: That does sound like it takes a lot of work and effort. So, what was one challenge you had to overcome to complete the study?
Dr. Diekfuss: So, one of the biggest challenges for a study like this was coordinating clinical, surgical, and research teams to both recruit and bring patients in, because we were bringing patients in pre-operatively, or right after their injury but before surgery, and then tracking them consistently over time. So, we weren't just doing one scan and drawing a conclusion; we were actually following athletes longitudinally with MRI before surgery and then at multiple time points.
In addition, another challenge with this is when using MRI, musculoskeletal imaging doesn't have as much software or open-source packages to analyze the data. And we were interested in the compartments or the segments of the graft as it healed, so we had to develop new analytic pipelines and new techniques to extract data from specific parts of the graft and then to translate that into meaningful outcomes that people can understand.
Melissa: So, has doing your research ever changed the way you think about potentially success, or patients, or how someone progresses?
Dr. Diekfuss: Yeah. So, this study had a lot to do with patients and progression. It reinforced something that's easy to forget in the field of sports medicine and orthopedics: that recovery from an ACL reconstruction or this type of injury, it's not just how someone feels in the moment, or how far they can jump, or if they say they're ready to go back into sport. There's a lot of biologic or complex changes that are happening with what we can't see, actually within the knee joint.
And what we saw in this paper is that, particularly three and six months after the ACL reconstruction, that the new graft wasn't healed the same way as the original uninjured ACL. And even at twelve months, it was appearing to get there but may not be fully back to its native state. So, it's just a reminder that progress from ACL reconstruction is multifaceted and can be slow, and helps explain when people ask, "Why does it take nine months or a year to- why can't I go back to sport faster?" It’s because the body just takes time, and you have to be patient for your body to fully heal before you get back to sport and reduce that risk of a secondary injury.
Melissa: So, in the future, where do you see this research going?
Dr. Diekfuss: The next step is connecting these imaging findings with more traditional clinical outcomes. So, we again showed that MRI can track the maturation of the quadriceps tendon autograft, with proximal or areas of the graft that are closer to the upper half of your body maturing a little bit slower, which may mean that part of the graft is more vulnerable to injury. However, what we need to do is then link these imaging data to clinical outcomes. So, things like self-reported pain, function, how well they jump, how well they move, how do they feel, and then link that to re-injury risk. So, do these MRI findings predict who’s going to re-injure their ACL or re-injure that graft?
And we also want to parse these data further to better understand why some patients show relatively slower graft healing versus others. So, we could look at males versus females, the type of physical therapy or rehabilitation they went through throughout that year to try to identify patients who are at higher risk or have a slower maturation process, which then could inform more personalized therapies or patient-specific recovery. But ultimately the goal is to move away from simply describing the ACL graft healing to using that information to inform personalized treatment approaches with better-informed clinical decisions after ACL reconstruction.
Melissa: Thank you so much for your insights.
Dr. Diekfuss: Thank you.
Melissa: Thanks for joining us for this episode of Behind the Breakthroughs Off the Field. I hope today's conversation offered a clearer look at the curiosity, care, and science behind the work happening at Emory. If you enjoyed this episode, feel free to explore the rest of the series, where each researcher brings a new perspective on injury prevention and human performance. Thanks for listening, and we'll see you next time.
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