Hideyuki Koga1, Jin Ye Yeo2
1Department of Joint Surgery and Sports medicine, Institute of Science Tokyo, Tokyo, Japan; 2AOJ AME Publishing Company
Correspondence to: Jin Ye Yeo. AOJ Editorial Office, AME Publishing Company. Email: aoj@amegroups.com
Expert introduction
Dr. Hideyuki Koga (Figure 1) is a professor at the Department of Joint Surgery and Sports Medicine, Institute of Science Tokyo (IST), which has been merged and renamed from Tokyo Medical and Dental University (TMDU) since October 2024.
Dr. Koga graduated from TMDU in 1999 and joined the Department of Orthopaedic Surgery, TMDU. After his clinical fellowship, he entered graduate school and defended PhD at TMDU in 2008 with the main topics regarding cartilage regeneration using mesenchymal stem cells. Then he went to Oslo Sports Trauma Research Center, Norway from 2008 until 2010. His research topic was knee anterior cruciate ligament (ACL) injury prevention, and clarified detailed ACL injury mechanisms. He is still working on injury prevention as a member of the scientific committee, IOC World Conference Prevention of Injury and Illness in Sport, and a member of the Academic Advisory Board, IOC Diploma in Sports Medicine.
Dr. Koga has been doing many double-bundle ACL reconstructions, reconstructions of multi-ligament knee injuries, as well as meniscus surgeries. He has done clinical and biomechanical research regarding meniscus preservation. He has developed a new surgical procedure called arthroscopic centralization to reduce/prevent meniscus extrusion. Until now he has published more than 250 papers, has given lectures, and had presentations at many international congresses. He is also working as a member of the scientific committee, ISAKOS, and a member of the program committee, ACL Study Group. He also serves on the editorial board of the Journal of Orthopaedic Science, Knee Surgery & Related Research, and Asia-Pacific Journal of Sports Medicine, Arthroscopy, Rehabilitation and Technology.
Figure 1 Dr. Hideyuki Koga
Interview
AOJ: What motivated you to specialize in sports medicine and orthopedic surgery, particularly focusing on knee ligament injuries?
Dr. Koga: There are so many athletes/patients who suffer from knee ligament injuries, especially anterior cruciate ligament (ACL) injuries. I have been focusing on the prevention of ACL injuries and the development of the best ACL reconstruction, and it is still imperfect. There is still so much room for improvement, which motivates me to find the best solutions to treat patients.
AOJ: Could you provide a brief overview of the current publications in meniscus preservation? Are there any recent findings that stood out to you?
Dr. Koga: In my opinion, recent topics for meniscus preservation are how to deal with meniscal extrusion and biology to enhance meniscus healing. There have been several centralization procedures to reduce extrusion published after my publication, and their clinical/biomechanical benefits have been proven. There are also new biological augmentations reported, some are already in clinical use and others are still in the experimental phase.
AOJ: Your work on ACL injuries and meniscus preservation has been groundbreaking. What are some of the most challenging aspects of this research, and how have you addressed them?
Dr. Koga: In terms of ACL injury mechanisms, the analyses were time-consuming but I was able to manage them. When I started this research, there were several mechanisms proposed and argued, and at that time “knee-in, toe-out”, knee valgus and external rotation was proposed as a main mechanism. I proposed a new mechanism based on our 3D model-based image-matching technique, in which a combination of knee valgus, internal rotation, and anterior tibial translation was the mechanism. At first, there were lots of accusations against my theory. But now my proposed mechanism is generally accepted and known as a first-reported detailed ACL injury mechanism.
Likewise, when I developed my centralization technique and presented it in congresses, there also were lots of accusations regarding over-constraint of meniscus, although no one had any solutions to meniscus extrusion at that time. I tried to convince everyone through clinical and biomechanical research following the publication of the surgical technique, and again, this surgical technique is now accepted and recognized all over the world.
AOJ: In your research on knee osteoarthritis (OA) prevention, what new strategies or technologies are you exploring to reduce the onset of this condition in athletes?
Dr. Koga: My concepts for knee preservation are to preserve the meniscus as much as possible, and to intervene in malalignment as early as possible. Both coronal and sagittal alignment affect knee biomechanics, for example, varus alignment would put too much load on the medial compartment, failing medial meniscus/cartilage repair. A large tibial slope would increase failure after ACL reconstruction as well as medial meniscus posterior root repair. So my concept, again, is to correct alignment to a mechanically neutral position by around-knee osteotomies (AKO) and preserve meniscal function as much as possible.
AOJ: The arthroscopic centralization technique you developed for meniscus preservation is innovative. What prompted this approach, and what impact do you see it having on the long-term health of patients?
Dr. Koga: When I came up with the idea of centralization, several papers started to show that extrusion was correlated with OA. I read some papers and just thought, “If it is extruded, why not put it back to its original position?” Then I talked to a colleague who was a shoulder surgeon, and he gave me some ideas for surgical procedures from the shoulder surgery’s perspective. After several improvements in the technique, I believe this centralization technique can restore meniscal function and prevent future OA progression in the long term, combined with AKO.
AOJ: With the advancements in biomechanics and surgical techniques, what future developments in sports medicine excite you the most?
Dr. Koga: Development in biological approach excites me the most. The healing rate after meniscal repair is still not satisfactory, and especially when I treat degenerative meniscus, the quality of the restored meniscus affects its function greatly. Biological augmentation for meniscal repair, and ideally, reversing the quality of the meniscus back to normal (some kind of anti-aging agent) is what I hope to achieve.
AOJ: As an Editorial Board Member, what are your expectations for AOJ?
Dr. Koga: Higher impact factor! For that, I would like to contribute.