Robotic UKA

Abstract

Unicompartmental knee arthroplasty (UKA) is a reliable, although technically challenging, treatment option for osteoarthritis. Successful clinical outcomes depend on accurate implant placement, lower limb alignment, and soft tissue balance intraoperatively. Robot-assisted systems aim to improve the surgical accuracy, precision, and reproducibility of clinical outcomes. Semi-active UKA systems with a minimally invasive approach have been developed and are becoming more interesting. These robotic systems can be either image-based or imageless. Recently, two robotic systems have been approved for UKA by the US Food and Drug Administration: the MAKO Robotic Arm, which is an image-based system, and the Navio Precision Free-Hand Sculptor (PFS), which is an image-free system. Several studies have shown that robotic UKA offers greater accuracy of the mechanical axis, implant positioning, and soft tissue balance than conventional UKA. They concluded that robot-assisted UKA achieved more reproducible, accurate, and precise bone cuts, suggesting that the system could improve surgical survivorship. Although robot-assisted UKA has a high capital cost, some studies have shown that it is cost-effective under the following conditions: (1) centers must perform at least 94 cases annually in (2) patients younger than age 67 years, and (3) the 2-year revision rate does not exceed 1.2%. Thus, these early results and cost-effectiveness analyses seem promising. The limitation of robotic surgery may be the longer learning curve regarding the operative time, although some studies reported that the robot-assisted UKA system significantly decreased the learning curve over that required for UKA with traditional instrumentation.