The Utility of Robotics in Total Knee Arthroplasty

Abstract

In the last decade, instrumentation for total knee arthroplasty (TKA) has improved the accuracy, reproducibility, and reliability of the procedure. In recent years, minimally invasive surgery (MIS) TKA introduced instrumentation that was reduced in size to fit within the smaller operative field. As the operative field becomes reduced in size, the impact and influence of technology becomes proportionately larger.¹ The introduction of computer navigation with MIS is an attempt to improve the surgeon’s visibility in a reduced operative field. The intended goal is to improve the position of the resection guides and ultimately the position of the final components, in essence, providing improved visualization in the limited field. This new technology is an enhancement tool or enabler in MIS TKA because, after registration of the anatomic landmarks, the instruments are dynamically tracked with real-time feedback on the angle and depth of the femoral and tibial resection. Currently, there are two types of computer-navigated systems for TKA: imaged-guided and imageless systems. Image-guided systems rely on data from preoperative radiographs or computed tomography (CT) scans that are registered into the computer system. Imageless navigation systems eliminate the need for preoperative imaging and rely on the registration of intraoperative landmarks, and then compare the registered data with a library of anatomic specimens recorded within the computer databank. The next distinctive feature is the mode of instrument tracking, which can be either by optical line of sight with a series of arrays that are detected by an infrared camera, or an electromagnetic (EM) system that utilizes trackers that are attached to the bone and an EM field generator. Each computer navigation system has their proponents. Either way, advocates of computer-navigated surgery have reported in clinical studies that navigation has shown an improvement in the accuracy of component position within 3° of the desired position over conventional instrumentation.²,³ The computer relies on the registration of anatomic landmarks and interprets this data to create a three-dimensional (3D) virtual model of the knee. Refinements in the process of collecting the landmark data will create a more accurate virtual model and guidance system. The ideal system should be simple to use, accurate, and reliable without interfering with the operative field and should serve as an enabler in the limited operative field, reliably reporting the knee alignment and intraoperative kinematics.⁴