Latest Advances in Robot-Assisted Knee Arthroplasty
Authors:   Imperial College Healthcare NHS Trust  President of CAOS UK (Computer Assisted Orthopaedic Surgery UK)  London, United Kingdom, Nathwani Dinesh , Shenoy Ravikiran ,   Lister Hospital, East & North Hertfordshire Hospital NHS Trust, Stevenage,  London, United Kingdom
Published: November 2021

In the longstanding pursuit of improving alignment and functional outcome in knee arthroplasty, technological evolution leading to robotic systems has now been introduced to the mainstream orthopaedic surgical world. This technology facilitates greater accuracy in implant placement, protects soft tissues, and achieves better balancing, while also allowing the potential to be more bone conserving. Robots currently in use in orthopaedic surgery can be classified into passive or haptic semi-active surgeon-guided systems. Using a virtual model of the knee joint, the robot system guides bone cuts and facilitates precise implant placement. In addition, small changes to bone resection can be made permitting deformity correction and balancing. This is achieved on-table by dynamic referencing, which enables live objective measurement of range of movements, stability, and gap balance throughout the range of motion. Preservation of ligaments and their unnecessary releases has been shown to reduce time to recovery and allow potentially better knee kinematics. Advances in robot technology in knee arthroplasty have led to the development of a variety of systems to execute the multiple steps in this procedure including using computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, plain radiographs (image based), or image-free systems. The combination of these images and on-table registering of bony landmarks allow the creation of a 3-dimensional (3D) virtual, but accurate, model of the knee during surgery. The various systems apply sculpting tools, burrs, or cutting saws to deliver the bone cuts or allow robots to guide placement of cutting blocks to ensure accurate pre-planned bone cuts. Intraoperative adjustments to bone resections can be made using a variety of tracker systems to measure joint movement and ligament balance to correct any malalignments while performing the surgery, so compound errors in the technique are avoided. Data from comparative studies suggest improved accuracy in implant placement in patients compared to conventional knee arthroplasty. Benefits of robot assistance have been demonstrated both in total knee arthroplasty and unicompartmental knee arthroplasty. Recent studies show a trend toward improved patient-reported outcomes and better patient satisfactions as well as earlier recoveries following robot-assisted knee arthroplasty. Early survivorship data has also shown a better survivorship with robot-assisted knee arthroplasty, although long-term survivorship data are awaited. An increase in familiarity, availability, and demand for this technology is driving innovations aimed at delivering a personalized approach to knee arthroplasty. This chapter will discuss the latest advances and look at the clinical research in relation to the robotic technological advancement comparing some of the different system approaches.