30 Day Trial

ORTHOKNOW content is posted to these pages in real time.

Monthly compilations are available in PDF form.

Voice of Industry

ORTHOWORLD Member Success Story: Focus on Science, Not Technique, says Orthopedic Surgeon and Academic

By Heather Tunstall, ORTHOWORLD  

Over the last five decades, the orthopedic career of Hendrik Delport, M.D., Ph.D. has evolved from surgeon to researcher to teacher to innovator.

His list of accomplishments is long, including the first clinical use of knee arthroscopy in the Waasland (East Flanders) area of Belgium, a degree in medical law and the designer and first implanter of Biomet's Performance Total Knee. He is CEO of Surgical Sensors and a consultant for Materialise, Gecko Biomedical, Vesalius Biocapital and Mobelife.

Over the last decade, Dr. Delport's focus has been on tissue engineering and stem cells in orthopedics, and he’s currently working on a European Medicine Agency Advanced Therapy Medicinal Product.

Dr. Delport's experience developing knee implants led him to realize that further advancement in total knee arthroscopy (TKA) would require a change in surgeon performance, not in device design. He returned to the lab for answers, and in 2013 earned his Ph.D. in Medical Sciences from KU Leuven, an accomplishment that he considers to be the greatest of his career.

We asked Dr. Delport to share insights from his varied career experiences. What would he do different if given the chance? "Nothing," he said.

What lessons have you learned during your career?

Dr. Delport: I have performed more than 12,000 hip and knee implantations. During TKA, in my opinion, strain in the ligament is the more relevant parameter and should be kept below 5% for microscopical damage, and below 10% for irreversible stretching. If the medial collateral ligament is strained above 5.14%, it will not regain its original length. Ligaments stretched beyond this threshold remain “stretched.”

I think we need a direct, accurate measurement of ligament length changes during surgery. In combination with a way to tune implant alignment, we aim to keep length changes within limits. Devices to improve knee joint balancing are already on the market, but they rely on indirect measurements. More importantly, they give their information at the end of the procedure, when all bone cuts are made. Drawing conclusions from pressure testing also remains indistinct.

Soft tissues in human joints, such as ligaments, tendons and the capsule, serve a passive mechanical (providing joint stability and determining joint kinematics) as well as a sensorial function. Up to now, mechanical function has been considered mainly during surgical procedures (e.g., while balancing the knee joint during TKA).

Recently, however, more and more orthopedic surgeons experience that this may not be sufficient for clinical success. Despite the use of ever-improving implant designs and more precise surgical techniques, a considerable number of patients (particularly after TKA) remain dissatisfied and suffer from reduced function compared to their healthy peers. This is an indication that the orthopedic community is missing some important aspect of working on joints.

We believe that this may be the sensorial role of the soft tissues, particularly the ligaments. Although it is not yet known exactly how ligaments sense deformation and strain, it is clear that they are capable of detecting quite small changes in length and reacting to those by influencing muscle tone. The relatively coarse joint balancing techniques used during orthopedic surgery are probably not sufficient to defer to this delicate sensorial function in many patients.

What can you share about the changes and new paths you took along your journey?

Dr. Delport: Some sections of our profession evolve very rapidly, especially from a technical standpoint. Others remain stagnant. Out-of-the-box thinking is necessary. For instance, we know that 15% to 20% of TKA patients are not satisfied. Even with new implants, patient-specific guides, navigation and robots, surgeons focus on alignment related to bony landmarks. The soft tissue envelope has been neglected for the last 40 years. My doctoral thesis was set to “The search of new pathways for TKA.” From this study, a start-up company, Surgical Sensors, was established.

What advice would you offer a young person entering orthopedics?

Dr. Delport: Do not concentrate on a single technique; instead, concentrate on basic science. Techniques are changing rapidly with technological evolution.