Is Robo-Doc the Future of Knee Replacement Surgery?

By Joshua Lindsey, MD |

As people live longer, more knees are wearing out, and more people are feeling the pain. If you’re one of those with severe knee pain, there’s some really great news as to share with you as well as some confusing news out there to clear up. Let’s sort through it.

First of all, you should know there’s no perfect solution to knee pain, including knee replacements. I’m hopeful that one day research will give us a new, more perfect tool, such as a way to replace worn out arthritic cartilage with healthy new smooth cartilage. That’s the holy grail of orthopedic medicine, but it’s far from a reality yet.

For long-term proven treatments that get you back to doing the things you love, knee replacement is the most effective remedy for the majority of people with severe debilitating pain. Millions of Americans, in fact, have new knees that have transformed their lives by reducing pain and increasing their mobility. That said, the procedure comes with two big challenges for orthopedic surgeons.

The first of those is correctly aligning the knee replacement. Because every person is truly unique, every knee requires unique alignment, and this is one of the main challenges with traditional knee replacement surgery. When it comes to aligning a knee implant in surgery, taking out the guesswork makes a big difference for a great number of patients.

The second challenge for surgeons is the level of complexity of the knee joint itself. The human knee joint does not act like a simple hinge as is natural to believe. As it flexes and bends, the knee actually rotates as it moves, making the motion a complex one. And the knee does the same thing in reverse as it straightens out again. Also crucial is that, again, knees come in just as many shapes and sizes as there are knees in the world. Each is unique. Even in the same patient, the right knee is different from the left.

One way to help solve the alignment issue is robotic assistance. To understand the importance of the robot, we have to consider how knee replacements are traditionally performed. The original way to align a new knee is using visual ques that aid a highly skilled surgeon. An alignment rod is the simplest surgical aid, and it’s still used today with good accuracy by some surgeons. Newer technology also currently in wide use are “custom cutting blocks” which is what all the major knee replacement companies offer if a surgeon wants to use them. These blocks are guides designed to fit the patient’s arthritic bone to help aid a highly skilled surgeon in properly aligning the implant. The blocks simply snap onto the patient’s arthritis bone and assist the surgeon in aligning cuts of the bone onto which the new hardware is fixed. This technique is similar to a traditional alignment rod in that both require a degree of improvising on the part of the surgeon. What this means is the surgeon has decisions to make during surgery regarding how to align the implant.

Enter the robot. Today, robots with very high price tags are available to assist surgeons with knee alignment. Robots are essentially replacing the old alignment rod. What robots are not doing, however, is adding any value to any patient’s surgery beyond being an alignment aid. And they are definitely NOT performing the surgery.

Regarding the second of the two main challenges faced by surgeons—the complexity of the joint and the uniqueness of each human knee—I have some exciting news. Until very recently, the available solution has been to make a symmetric implant of several varying sizes that will fit closely enough to satisfy the majority of patients. The surgeon chooses the closest size to the patient’s original knee before shaping the patient’s bone to make it fit. In other words, a surgeon may accurately measure you to be a size 5.3. However, the only options available are a size 5 or a size 6. Using the cutting blocks then, a surgeon will fashion a patient’s 5.3 knee to fit a Size 5 implant. If another patient’s knee is a 5.8, then that knee is shaped to fit a size 6.

To be clear, using a robot does not change this problem of fit. The machine is simply an expensive alignment aid and does not affect the selection or design of the implant.

The good news is you no longer have to accept an off-the-shelf knee and the 5 vs 6 sizing problem in my example. The knee replacements I use are the most advanced technology available, and they solve both the alignment and the fit problems in one, giving you a new knee that fits you and only you. I use the ConforMIS knee which is manufactured individually for each patient, one knee at a time. It’s the only knee that combines the best options available for both alignment and fit of the implant.

The ConforMIS knee comes in its own individual kit along with precision alignment aids specifically customized for each patient. More importantly yet is that the implant itself is computer designed to fit the unique anatomy of only one patient’s knee – yours. Because it’s a completely custom part, each one comes with a unique serial number, and there is only one like it in the world.

The curves of every ConforMIS implant will always EXACTLY match my patient’s natural knee. This is achieved thanks to an original multistep process that includes a CT scan of the patient and a sophisticated computer assisted design (CAD) program prior to the knee being manufactured. Each unique knee also comes complete with an entirely unique system of custom jigs created to fit my patient’s bone. The jigs are so precise, that when it comes to properly aligning the implant the procedure is an exact one with no estimating necessary in the operating room. We know what the optimal alignment is because the plan is set in place when the implant is made and the guides allow me to flawlessly achieve that alignment every time. The result is that each custom knee fits exactly as it should.

Custom ConforMIS implants cannot be used with robots. Instead they are always accurately placed by a skilled surgeon using the custom jigs that perfectly fit the patient’s bone.

In the future, we may find a solution to replace worn out cartilage with new cartilage. Until that is possible, we will continually be working to perfect the total knee replacement. I believe that the ConforMIS knee is currently the best available solution for knee replacement. My personal rule of thumb is to always do for all my patients what I would want for myself or my family. The ConforMIS knee meets that high standard.

It’s not easy for patients to learn about the many technologies that may impact their surgical outcomes. The use of a robot to assist in surgery might sound like something from a science fiction dream, yet the basic reality is it’s simply acting as an aid to alignment. And it unfortunately does nothing to address the issue of the complexity of the human knee. The other good news is that greater than 50,000 of these Custom Knees have been implanted world wide, so although this technology is new, it has been vetted.

The ConforMIS knee combines the best of both worlds with advancements for both alignment and implant sizing and shape. And that’s why I’m delighted to be bringing this technology to the Tri-State area of southwest Wisconsin.