Editorial Comment: Selected Proceedings from the 2019 European Knee Society Meetings

With great pride, my colleagues and I from the European Knee Society (EKS) present our second proceedings issue in Clinical Orthopaedics and Related Research®. The EKS seeks to advance knowledge of degenerative knee pathology and knee arthroplasty, create an environment to enhance education and research, and promote high professional standards as a way to provide the best care possible to patients with degenerative knee problems.

As a relatively young society—EKS was founded in 2015—we have experienced challenges as we have attempted to create a true European society, owing to operational difficulties arising from many cultural differences across our diverse constituencies. But we believe that we are on the right track. Indeed, we are hopeful about our future because EKS now is the leading European society for the degenerative knee, with open meetings attended by hundreds of surgeons from all around the world, large demand for membership, and international collaborations with scientific societies at the highest level.

As the Guest Editor of these proceedings in CORR®, I’m in the privileged position of seeing what my colleagues are working on. Conspicuously absent, not just from these proceedings but also from our recent meetings, is original research on the subject of robotic-assisted TKA. I wondered why this might be, since robotics seems to be a front-of-mind innovation at the moment. I know my colleagues in the EKS well enough to know what most of them use in the operating room. My best estimate is that about one in five of them uses robotic assistance at least for some of their TKA procedures. And yet at our recent meetings, only a minority of presentations were given on the subject of robotic-assisted surgery.

It’s not for a lack of peer-reviewed science. A variety of systems have been tested [^{3, 6, 8}], some even using robust comparative trial study designs [^{1, 7, 11}].

But a careful look at the history of robotics in knee surgery suggests that it followed the typical orthopaedic reinvention cycle, where an approach drifts in [^{10, 12}] and out of fashion and back in again [^{2, 4, 8}], as engineers and their companies develop new approaches, and those approaches go hunting for a surgical indication.

Robotic-assisted knee surgery has tremendous intuitive appeal. Many orthopaedic surgeons are comfortable embracing new approaches, and may even do so preferentially; it seems a part of the natural temperament of an orthopaedic surgeon to put his or her hands on a new tool and try it out. Patients find it appealing; in an era of self-driving cars and artificial intelligence, why are knee surgeons using mechanical jigs that would look entirely at home in a 19^th-century cabinetmaking shop?

Those intuitive reactions favoring the novel over the simple make it possible for an expensive and unproven new technology like robotics to gain traction in TKA. It’s not that robotic-assisted TKA is ineffective; plenty of studies have shown it’s possible to get very precise alignment using these tools [^{2, 3, 6, 8}]. It’s that these tools are expensive [²], they add time to the surgical procedure [²], and no well-designed studies have proven that robotic TKA surgery delivers any benefits that a patient or a healthcare system might perceive, such as improvement in knee scores over the longer term or a reduction in the risk of aseptic loosening or revision. Given that we expect implant survival in the vast majority of patients undergoing TKA to extend well into the second decade and beyond [⁹], and given that we cannot link patient dissatisfaction in most patients to small differences in component alignment (the endpoint that robot-assisted TKA might be able to minimize), it may be difficult for future studies of robotic knee surgery to prove that it adds value compared to older and less expensive technologies [^{5, 13, 14}].

Stated another way, based on what we now know, Robotics 3.0 appears to be an expensive intervention that has a lot of intuitive appeal (both to surgeons and their patients; marketing one’s surgical robot is a sure way to get the office phone ringing), but no evidence-based value proposition behind it, and little hope that such a value proposition can even be made. In an era when all of us have responsibilities to be good stewards of the limited resources still available, I’m completely comfortable with clinician scientists exploring robotic surgery in rigorous clinical trials. In fact, upon reflection, I’m glad that these EKS proceedings (and our meetings) do not include a bunch of case series about surgeons’ “experiences” with robotic-assisted TKA. I am looking forward, however, to future robust studies about robotics from our members, preferentially from those not consulting for the industry, about the costs and value-add—if any—of this technology.

I’m excited about the content of this year’s EKS proceedings in CORR. I was gratified by the quality and breadth of the work contained herein, and by the many not-so-obvious and certainly noncommercial themes my colleagues have covered. I heartily recommend the work published in this year’s EKS proceedings in CORR to readers, and my EKS colleagues and I look forward to working with CORR again next year on publishing the proceedings of our upcoming meetings.

Fig. 1: Emmanuel Thienpont MD, MBA, PhD