Matthew Deren, MD
Published 7/30/2025
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Ahmed K. Emara, MD
The increasing utilization of robotic technologies in orthopaedic surgery, particularly in joint arthroplasty, is reshaping the field at a remarkable pace. With growing adoption in both academic and private settings, robotic-assisted total hip arthroplasty (THA) and total knee arthroplasty (TKA) have sparked important conversations — not only about their indications and impact on clinical outcomes, but also about their implications for surgical education, resident preparedness, and the evolving role of the orthopaedic surgeon.
Among those leading this transformation is Matthew Deren, MD, director of the Adult Reconstruction Fellowship at Cleveland Clinic, who has been at the forefront of integrating robotic systems into arthroplasty practice over the past decade. As an early adopter, he brings a wealth of experience in both manual and robotic-assisted techniques, with a special focus on indications and applications in complex primary and revision procedures. Dr. Deren shared his insights on this critical and timely topic with AAOS Now.
AAOS Now: How does robotic-assisted surgery’s learning curve compare to manual techniques?
Dr. Deren: Literature tells us that robotic arthroplasty has a learning curve somewhere between 16 and 40 cases, depending on case complexity and surgeon volume. It probably depends on how you utilize the technology and make it work for your particular workflow.
In my personal experience, I was essentially time-neutral when using a robot, but this is because I often would take very conservative tibial cuts requiring a recut. Using the balancing software of robotic-assisted TKA, I was able to perform all the soft-tissue balancing before any cuts, which essentially made up for the time required for registration and insertion of the arrays.
More than just the physical procedure, there is somewhat of a learning curve when it comes to understanding how the planned balance may change with different amounts of osteophyte formation, bigger releases, and the cuts themselves. I think the precision and accuracy of a robot allow us to start to understand more of what we are doing in joint replacement at a much more precise level than we did previously.
Is intraoperative efficiency affected positively or negatively using robotics?
The time is really neutral once you have developed your workflow in robotic-assisted joint replacements. The real benefit is the precision and ability to cut and even recut very quickly, without the need for blocks in some systems. I think this is an extremely useful part of robotic-assisted joint replacements, and one that has allowed me to actually save time.
How do you envision robotic surgery evolving?
I think over the next five to 10 years, we are going to see some tremendous advancements in the technology that we are using: the ability to personalize knee replacements based on preoperative deformity and intraoperative correction, with correlation with database studies on outcomes; smaller robotic systems that may even include handheld smart tools; and the ability to perform the surgeries without having to place pins and arrays through the bone. What is next on the horizon is likely more widespread use in revision arthroplasty.
How do you see the influence of industry on the adoption of robotic technologies?
The rise of robotic surgery in orthopaedics has, unsurprisingly, paralleled increased involvement from industry — a relationship that warrants careful scrutiny. While these partnerships have undeniably accelerated innovation and improved system availability, they also carry the potential to shape the narrative in ways that blur the lines between evidence-based findings and promotional enthusiasm. Early literature on robotic arthroplasty often reflected this dynamic. Early studies assessing these technologies were more likely to be industry-sponsored, single-center, and of modest methodological quality. These studies tended to report favorable outcomes for robotics, though the differences were marginal and rarely sufficient to change clinical practice guidelines. This was followed more recently by a tangible shift in the type and quality of investigations; as adoption has broadened, we’ve seen a welcome shift toward higher-quality, multi-institutional, and more independent studies. These studies consistently demonstrate reduced alignment outliers — an objective benefit of robotic precision — but continue to show little to no difference in clinical outcomes, patient satisfaction, or cost-effectiveness compared to manual techniques. So the technology delivers on what it promises radiographically, but whether that translates into long-term clinical benefit remains an open question.
We know from historical data that malalignment in THA and TKA is associated with poorer survivorship and, in the case of hips, higher dislocation rates. That gives some reason to believe that the precision of robotics may eventually yield downstream clinical advantages given sufficient long-term follow-up. But at present, this remains a hypothesis in search of evidence, not a conclusion we can yet draw with confidence.
A potential concern in the expanding use of robotic platforms is their coupling with company-specific implants, which can limit surgical flexibility and influence implant selection. However, with few exceptions, the vast majority of implants available in the United States demonstrate comparable survivorship and patient-reported outcomes. Furthermore, most major manufacturers offer a range of implant designs, making it unlikely that patients are denied access to a particular implant solely due to the use of a robotic system. In many ways, a surgeon’s affinity to a robotic system can be likened to their preference of a certain manual system’s instrumentation or cutting jig.
Do you believe manual arthroplasty will eventually become obsolete?
I am not sure if “obsolete” is the right word, but I do think that the real benefits of robotic-assisted arthroplasty will make this the gold standard for joint replacements in the future. There are very few fields, in all of industry, in which robotics have entered and then not succeeded. I think we are seeing this now with joint replacements.
Do you find that robotic assistance leads to better alignment, regardless of surgeon experience?
Some of the strongest papers that have been published on robotic-assisted TKA show the precision and accuracy of this technology. Having the ability to cut and place the implants exactly where you have planned allows for what I believe will be a “shifting of the bell curve,” such that low-volume surgeons can place knee and hip replacements as accurately as high-volume expert surgeons. It is one of the greatest features of this technology.
Are robotic-assisted arthroplasty outcomes surgeon-dependent or more consistent across users?
The difficulty with a lot of the outcome studies currently is that many of them are performed at academic institutions, with expert surgeons comparing against their manual techniques or partners performing manual surgery. I think a more interesting study would be to compare lower-volume surgeons using robots to try to measure their outcomes, although I am not aware of this literature at this point. There are two hypotheses to this question: The first is that robotic surgery would help lower-volume surgeons place the implants in the target alignment and positioning more reliably. The other suggests that false “dependence” on robotic technology may lead surgeons who are otherwise not as proficient in arthroplasty to perform surgeries that they may not be adequately trained to do, and this can have disastrous consequences. After all, it is the quality of the surgery that drives outcomes, regardless of the implemented tools.
What advances in robotic technology are you most excited about?
The prospect of using it in revisions. Our total knee replacements, total hip replacements, and conversions of partial to total knee replacements using a robot have created such a high level of accuracy and precision while redoing the surgeries. I look forward to seeing that same level of accuracy and precision in the revision world. I particularly see this is important in complex revision hip arthroplasty, where the remaining bone may be minimal and the ability to use a robotic arm to place implants precisely in the correct position — reamed to a submillimeter level exactly where you have planned — is very exciting.
Are there cases in which you choose not to use robotics? If so, why?
I still perform some of my hip replacements without the use of robotics. The downside as an anterior approach surgeon is that I have to wear lead and use fluoroscopy during the surgery, which has its own drawbacks. However, the technique has worked well for me in the past, so I would like to continue doing it and teaching my fellows and residents this technique.
How often do you utilize robotics in revision arthroplasty surgery, and what factors influence that decision?
All of the partial knee replacements that I revise to TKA, I use a robot for these surgeries. The ability to balance the knee, shift the implants to the remaining bone, and often use primary implants instead of revision implants has made these surgeries very reproducible. While possible, I have yet to use a robot for TKA revisions.
On the hip side, I have begun using a robot to help with acetabular reaming and positioning of the acetabular component. I have found that the reaming is so precise in these cases that my press-fit is often better than I could obtain with a manual technique. Upcoming robotic generations that are currently in limited release promise a more streamlined THA revision experience, but that is yet to be validated.
In your opinion, what are the biggest barriers to the adoption of robotic arthroplasty?
Hospital administration. Placing a robot at an institution is expensive and requires multiple levels of contract negotiations with the vendor and the implants. This is probably the biggest burden to implementation of this technology at a systemwide level. That being said, and as outlined earlier, robotic arthroplasty is not a “critical fix” — we do know that, to date, we cannot establish superiority of robotic arthroplasty over its manual counterpart. However, we do know from the most recent trends projection by Khan et al that nationwide adoption is increasing exponentially and may be projected at 70% of the total TKA volume by 2030.
Do you think experienced surgeons are more hesitant to adopt robotic techniques? If so, why?
“If it ain’t broke, don’t fix it.” This is often the mindset that I think we have, especially as more experienced surgeons, in implementing new techniques and technology, and that is totally acceptable, given that we cannot establish superiority of robotic surgery at this point in time. However, innovation drives these fields. By promoting and selectively embracing innovation, we can move the entire field forward to improve care for our patients.
Have you ever had to cancel a robotic case or convert to manual mid-procedure due to system malfunction or software issues?
I have never had to do this. Any problem we have had, we have been able to troubleshoot quickly and continue the robotic-assisted case with minimal delay.
How do patients perceive the involvement of robotic assistance in their surgery? Have you seen patients who are hesitant to have their surgery “done by a robot”?
In general, patients are usually very receptive to the idea of having their surgery performed with robotic assistance. Occasionally, there is one who does not want the surgery done by a robot. This often takes a little bit of discussion with the patient as to what the robot actually does, and when they understand that it is not autonomous and is merely a tool that helps us in our craft, they are very receptive to the idea.
Ahmed K. Emara, MD, is a senior orthopaedic surgery resident at Cleveland Clinic. Dr. Emara is chair of the AAOS Resident Assembly Education Committee and a member of the AAOS Now Editorial Board.
Reference
- Khan ST, Emara AK, Zhou G, et al. Robotic-assisted total knee arthroplasty in the USA: nationwide adoption trends towards 70% by 2030. J Clin Orthop Trauma. 2025;68:103069. doi: 10.1016/j.jcot.2025.103069