GET TO KNOW OUR RESEARCH TEAM

Gregory S. DiFelice, MD Founder & Chairman

Dr. Gregory S. DiFelice is a board-certified Orthopaedic Surgeon at Hospital for Special Surgery in New York. He is a surgical innovator and has developed several cutting-edge surgical techniques that allow him to save a patients’ torn ligaments, rather than replacing them, which is the current standard of care. His minimally invasive approach can cut the recovery time by more than half. His work with underserved communities for 15 years compelled him to investigate these less invasive procedures for the treatment of ligament injuries of the knee, and has contributed to a worldwide resurgence of interest in a PRESERVATION FIRST® approach to such injuries. He and his research team have published over 50 peer-reviewed articles and book chapters in the past five years on the topic of ligament preservation. This has resulted in two team members, Dr. DiFelice and Dr. van der List, being included in the top 50 most published authors in the world on the topic of ACL Injuries over the past decade. This journey, and the difficulties that he experienced challenging the surgical status quo, led him to establishing this foundation with the goal of supporting innovative surgical research. When he is not in surgery or at his clinic, he enjoys spending time with his family, skiing, playing his guitar, cooking, and baking up some wonderful treats.

Jelle van der List, MD, PhD

Jelle van der List is a current orthopaedic surgery resident in Amsterdam (the Netherlands). Since 2016 he has been working with Dr. DiFelice on research on the topic of primary anterior cruciate ligament repair and recently obtained his PhD on this topic, which was mainly based on the research that they have worked on. He aims to finish his residency in the summer 2023 and start a sports medicine fellowship.”

Robert J. O'Brien, DrPH, MHS, PA-C

Robert J. O'Brien, DrPH, MHS, PA-C, joined DiFelice Orthopaedics 2015. His clinical work includes managing perioperative care for patients and first assisting in the operating room. Additionally, he has been involved in several research efforts to further analyze the role of ligament preservation. His professional interests include sports injury prevention, surgical innovation, preventive medicine, evidence-based care, and the effective integration of public health concepts into clinical medicine. He holds a doctoral degree in public health, and continues to work both clinically and in academics.

Daan Vermeijden, MD

Daan Vermeijden is currently working as a resident not in training in Orthopaedic Surgery in Hilversum, the Netherlands, and was just officially accepted into the residency program. After obtaining his Medical Degree, he spent 18 months at the Hospital for Special Surgery (HSS) in New York City doing research with Dr. DiFelice on the subject of primary repair of the anterior cruciate ligament. During this period, they investigated the indications and outcomes of this procedure and published numerous manuscripts in peer-reviewed journals. After his amazing time in New York, he returned to Amsterdam to do his residency in Orthopaedic Surgery. He is also working part-time on completing his PhD on the topic of primary ACL repair.

Sebastian Rilk, MD

Sebastian Rilk is a MD from the Medical University of Vienna, Austria and joined the research team as a postdoctoral researcher in 2022. While an injury ended his ice hockey career and led him to pursue medicine, it was his medical school experience as an orthopedics fellow in Vienna that led him to HSS and Dr. DiFelice in early 2022. Sebastian is currently working on his PhD on the topic of bone and joint regeneration in addition to his work at HSS. Sebastian is passionate about ice hockey and environmentalism and enjoys skiing and tennis in his free time.

Gabriel Goodhart

Cash Goodhart joined us as a research coordinator working with Dr. DiFelice. He is originally from Dallas, Texas where he lived before attending Princeton University as an undergraduate. While at Princeton, he majored in Ecology and Evolutionary Biology, while also playing varsity football. In the future, he has intentions of attending medical school and continuing research in the orthopedic field.

Fidelius von Rehlingen-Prinz, MD

Dr. med. Fidelius von Rehlingen-Prinz is a fifth-year resident at UKE University Hospital of Hamburg, who is joining our team as a Research Fellow. Fidelius has a strong passion for orthopedic and sports medicine research and is an active member of several European arthroscopic surgery societies.