The VELYSTM Robotic-Assisted Solution for Total Knee Arthroplasty (TKA) burst onto the market in 2021, muscling in with various other robots on the market including the already well known Stryker Mako (TKA) system, which was launched in 2017. The VELYS robot reached the European market in 2023, after which it mainly saw uptake in the UK private sector but not the public facing National Health Service. However, as of 2025, Broadgreen Hospital in Liverpool became the first NHS hospital in the UK to use the VELYS robotic solution for a total knee replacement.
As you can imagine, this caused an appreciable stir, resulting in a few national news headlines. And, as it so happened, I rotated to this NHS Trust just as the robot arrived and patients began having their knees replaced with this exciting bit of kit…
The VELYS Robotic-Assisted Solution was developed and produced by DePuy Synthes, a subsidiary company of the American Pharma, BioTech, and MedTech behemoth Johnson and Johnson (J&J). The system purports to improve surgical outcomes through the provision of real time feedback and increased accuracy for the operating surgeons. One of the major benefits is that it does not require any CT scans to be uploaded, instead relying on a live navigation system which is calibrated when the system is set up intraoperatively. The equipment itself comprises two screens, one of which remains unsterile and has a camera/sensor on top of it, and a separate unit with a robotic arm on which the saw is mounted.
Having had an initial practise run on the VELYS system at the J&J MedTech stand at the most recent British Orthopaedic Association Annual Congress in Birmingham, I gained a rough understanding of the principles of the kit and what constituted the “robotic” element. However, it’s a different ball game in real life and takes a real learning curve to develop proficiency.
To break it down into more digestible morsels, I’ve outlined an overview of the relevant details below:
- 🖥️ The system utilises a live camera-sensor interface to track the position of the leg in real time. Critically, the camera must be able to see the sensor array at all times otherwise the femur/tibia/saw indicators on the screen turn red and progression through subsequent steps is halted.
- 🔪 The approach to the knee is mostly standard, however, the main modifications are that the synovium over the anterior aspect of the distal femur must be excised to expose the bony surface, and the distal part of the incision must be extended past the tibial tuberosity to expose the anterior border of the tibia distal to the zone of resection. This extra exposure is necessitated for the attachment of the sensors to the femur and tibia. This sensory array is how the tibia and femur can be tracked in real time by the camera on the stack.
- 📊 The calibration is performed next, firstly taking the knee through the full range of motion and circling the hip to establish the centre of rotation, then using a handheld sensor to identify specific bony landmarks. Each step on the screen is completed until the VELYS software has constructed a 3D image of the leg in space. Critically, the handheld sensor has to always face the camera otherwise the system does not recognise any of the “drawing” over relevant landmarks.
- 🦿The resection parameters are then programmed into the system based on the anticipated implant size and the balance of the knee using the VELYS PROADJUSTTM planning system. The coronal and sagittal balance is assessed at this point using the ACCUBALANCETM graph by taking the knee through its full range of motion. Adjusting each of the parameters, from bony resections, including varus and valgus angulation, to impant size, will adjust the flexion and extension gap in real time, allowing the surgeon to curate their bony resections and achieve the best balance for the implanted knee.
- 🪚 The bony resections are then completed by a robotically controlled saw, i.e. a saw attached to a robotic arm, using the VELYS ADAPTIVE TRACKINGTM technology. – importantly, any deviation from the programmed plane will render the saw inactivated so you just have to let the saw take its own path. This ensures your bony resection is performed exactly as programmed. However, the saw does not include any haptic feedback or depth perception so it’s down to the surgeon to ensure the saw travels in a safe corridor and plunging is avoided. Accordingly, it’s critical that the operating surgeon has an extensive pre-existing understanding of how to perform a well balanced total knee arthroplasty without the robotic-assisted solution.
So, having had an overview of how the robotic system works, let’s move onto how to maximise effectiveness in robotic cases when scrubbed as the first assistant. But before we start, I feel compelled to preface this section by giving you the most important bit of advice first. Start stretching. Do yoga. Practice pilates. You need to be as limber as possible for these cases. If you don’t exhibit skills just shy of those of a professional contortionist, then you’re already on the back foot. Jus’ saying.. more on this below ⬇️.
- Learn to retract whilst staying out of the way of the sensory arrays on the leg. The arrays are positioned just outside of the surgical field but coincidentally in the exact areas from which you would normally retract. Not only this, but the camera will usually need to see both the femoral and tibial arrays at the same time so there’s no hiding one whilst exposing the other, otherwise you won’t be able to proceed with the next step of the operation. So you have to be able to provide enough force to ensure adequate retraction whilst using a longer lever arm.
- Always be vigilant during the case and provide an extra pair of eyes. It’s really easy to lose spatial awareness, especially when setting up and preparing the case, so there’s an increased risk of desterilisation, missing key steps in the operation, and equipment falling on the floor, such as the suction.
- Learn the work flow of the VELYS system. Knowing how the software works will pay dividends when troubleshooting, especially without the presence of a Sales Representative to provide intraoperative support. Often, the instructions on screen can be confusing and it can be a challenge to navigate the menu, interpret the next steps, or return to a previous screen. Readjusting resection parameters is probably the most fiddly aspect, as you have to confirm the resection and then go back to the PROADJUST screen to reprogramme the resection, which can bring up a multitude of error messages.
- Place the Bair hugger as high up the patient as possible, or try to use a different type of intraoperative patient warmer. If the Bair hugger is placed in the usual position, then the inflation of it causes the drapes to billow up and obscure the femoral array, thereby preventing the camera from sensing it.
- Remember that the operation is still a TKA so it’s important to keep the flow going despite the robot. In a similar vein to point 2, it’s important to stay focused and not become overly distracted by the new equipment.
- During set up, the sterile draped robot needs to be dismounted from the base station and attached to the bed rail using brackets and bolts. This docking process can be difficult, as the robot is heavy and, if improperly secured, can fall off the bed and onto the floor thereby becoming desterilised or worse, damaged. It’s therefore a good idea to help this process by holding onto the sterile draped robot as it approaches the bed rail and providing a birdseye observation of whether the brackets have engaged with bed rail or not. I suppose a sensible modification would be to attach the robot to the bed rail before the sterile draping takes place, but I’m not 100% certain if that’s currently an option.
- Another thing to be mindful of is the slack in the sterile drapes. If the sterile drapes are applied too snugly then they can tighten during mobilisation of the robot and precluding any movement, risking the drapes tearing and desterilising the operative field.
- If performing any bony resections, remember to relax and follow the plane of the saw, applying firm and careful control to the direction and depth of travel rather than fighting with the robotic arm. It’s a pretty heavy bit of kit and so takes a lot of concentration but can flow really nicely once you’ve adapted to the feel of it. A good thing to do is to practice on dry bone models as soon as you can.
So these are my top tips for fellow Registrar Trauma & Orthopaedic Surgeons and Surgical First Assistants from my experience of the VELYS Robotic-Assisted Solution. It’s a great system when it works smoothly and all the kinks are ironed out. As with any other operation, a good assistant can be the make or break factor, so make sure you level up your skills and jump on this brilliant learning curve!
I’d love to hear your feedback and experience so drop me a message on here or via Instagram!
Vasudev Zaver 