Accuracy and early outcomes of robotic-assisted total knee arthroplasty

Some robotic total knee arthroplasties (TKAs) have been taking place since the early 2000s, but modern TKA with the latest generation of haptic-controlled robotic arm-assisted technology started in 2016 [1]. Since then, orthopedic surgeons have witnessed a rapid evolution of robotic systems, and during this ongoing journey, robotic-assisted TKAs have become an integral part of the orthopedic surgeon’s repertoire. The overarching goal is to find ways to better plan TKAs to provide better outcomes for patients. In the current landscape, a number of robotic systems have entered the market, yet the fast adoption rate may well outweigh the rate at which results are collated and published, and the relatively recent introduction of some systems means only short-term results and few mid-term results are available. It is critical that each system is evaluated separately as the data from one technology cannot be generalized to others. Nevertheless, the short-term results are promising overall. Learn more about accuracy and early outcomes of robotic-assisted TKAs with Fares Haddad, University College London and University College London Hospitals, London, UK, and take a closer look at the short-term outcomes showing decreased inflammatory responses after robotic-assisted TKA, less pain, and better early recovery.

Robotic-assisted total knee arthroplasty: an overview of systems

“When we ask ourselves, what can we do to make a TKA better for the patients, we think about planning in a more personalized way, making the correct bone cuts, minimizing soft-tissue damage, choosing the correct size and orientation of implants and correctly placing the knee implants for our patients,” comments Fares Haddad. “This is why we are here,” he adds, and this is where the use of robotic-assisted TKA could have an important role in patient-centered or personalized healthcare. At the present time, several different robotic systems for TKA are in use. These systems vary not only in the input for the planning but in the execution of the cuts, whether they are active or semiactive, use haptic feedback, or are open or closed systems, the latter pertaining to whether or not the system restricts the use of implants to those produced by the same manufacturer (a closed system) [2]. More importantly, as Haddad notes “the amount of research and data generated on these systems varies, and each must be evaluated on its own merits”.

To provide an overview of robotic systems, Walgrave and Oussedik [2] conducted a detailed, objective, comparative review in 2022 of five different robotic-assisted systems for TKA. At the time, the active robotic arm-assisted computer-assisted surgery (CAS) system from DePuy Synthes (VELYS, Johnson & Johnson, USA) did not yet have CE marking and was thus not included in their review [2]. The included systems were an active and partially autonomous system with autonomous burring (TSolution One, THINK Surgical, USA), a semiactive robotic arm-assisted CAS system with haptic feedback and virtual boundaries (MAKO SmartRobotics, Robotic Arm Interactive Orthopaedic System, Stryker, USA), a semiactive robotic arm-assisted CAS system with a handheld saw (ROSA Knee System, Zimmer Biomet, Canada), a hand-held semiactive CAS system with smart burr and virtual boundaries (CORI Surgical System, Smith & Nephew, UK), and a cutting jig-based robotic system mounted to the knee of the patient with a handheld saw (OMNIBotics, Corin, Cirencester, UK) [2].

When it comes to planning, the data needed by the robotic systems varies. Walgrave and Oussedik [2] noted that both the MAKO system and TSolution One require preoperative computed tomography (CT) scans of the patient’s knee and leg, whereas plain x-rays are used in the ROSA system. In contrast, the CORI system and OMNIBotics work without images, an additional feature also of the ROSA system, with all imageless systems relying on mapping of the knee intraoperatively to produce a 3D model of the knee.

Although robotic-assisted TKAs have been shown to have increased accuracy over conventional TKA [2], the level of accuracy achieved will vary depending on the system used. Having haptic boundaries and a robotic arm to control the cuts leads to more accurate cuts in the sense that inappropriate bone or soft-tissue cuts are not made, which is an important safety as well as accuracy issue. This is due to inherent design or operation differences, which impact how bone cuts are made and the level of possible soft-tissue damage. In their appraisal of the different robotic systems, Walgrave et al [2] awarded a high level of accuracy to robotic systems with a robotic arm-mounted cutting tool, haptic feedback, virtual boundaries, or fully active computer-assisted surgery, followed by a medium level of accuracy to those with a handheld bone preparation tool and virtual boundaries, and a low level of accuracy to those with a robotic-controlled cutting jig and a manually controlled saw. Haddad comments, ...