# Robotic Systems and Navigation Techniques in Orthopedics: A Historical Review
## 1 Introduction  
In 1954, [PERSON] invented the first digitally operated and programmable robot (later known as the Unimate) in the world, which is viewed as the foundation of the modern robotics industry [1]. Together with [PERSON], they founded the first robotics company in the world named Unimation. The company developed the first Unimate robot based on [PERSON]'s patent and sold it to General Motors in 1960 to be used to lift and stack hot pieces of metal [2]. Since then, robots have continually been improved, and have spread their applications to the surgical field. In 1985, the first robotic surgical system, Puma 560, was used for neurosurgical biopsies guided by computed tomography (CT) images [2, 3]. In the early 1990s, Minerva was introduced as the next-generation neurosurgical robot [4]. In 1988, ROBODOC (Integrated Surgical Systems, DE, USA) was introduced in orthopedics [4]. In the same year, PROBOT performed a clinical trial at Imperial College London with the earliest robotic procedure in urology. In 1993, a robotic arm called AESOP (Automated Endoscopic System for Optimal Positioning) (Computer Motion, Inc., Santa Barbara, CA, USA) was developed to assist in holding and positioning a laparoscopic camera. In 1998,both the ZEUS robotic surgical system (Computer Motion, Inc., Santa Barbara, CA, USA) and the da Vinci surgical system (Intuitive Surgical, Sunnyvale, CA, USA) were introduced into the market for use in teleoperated surgery [4], with the latter receiving the Food and Drug Administration (FDA) approval in 2000 for use in general laparoscopic surgery, which is considered legendary in the field of surgical robotics. Thereafter, medical and surgical robotics started to boom in various fields. Minimally invasive surgery (MIS) allows the surgeon to conduct surgical procedures through much smaller incisions than traditional open surgery, thus having a faster recovery rate and shorter rehabilitation time as well as less pain for the patient [5]. Robot-assisted MIS involves a robot to improve the quality and precision of surgical procedures. Since the da Vinci surgical system was approved by the Food and Drug Administration (FDA) in 2000, the development and deployment of various robot-assisted MIS systems have been largely expedited [6; 7]. With the rapid advancement of robotic techniques in recent decades, robotic systems have been widely used in various medical fields, such as neurological, laparoscopy, radiosurgery, prosthetics, rehabilitation, orthopedics, ophthalmology, and more [5; 8; 9; 10]: for example, the da Vinci surgical system (Intuitive Surgical, Sunnyvale, CA, USA) and RAVEN II (University of Washington, and University of California, Santa Cruz, CA, USA) for use in teleoperated laparoscopic surgery [8; 11; 12], the CyberKnife System (Accuracy Inc., Sunnyvale, CA, USA) for use in radiosurgery [13], and the JHU Steady-Hand Robot for use in retinal microsurgery [14; 15; 16]. These robotic systems and techniques are transforming the conventional ways to perform surgical procedures in a large variety of fields. Through decades of technique evolution and clinical evaluations in orthopedic surgeries, plenty of studies have proven that robotic systems and navigation techniques can be beneficial in improving and enhancing surgical outcomes, such as increasing the accuracy and precision of bone cutting and component alignment, reducing operative time, and enhancing patients' satisfaction [17; 18; 19]. Numerous review papers on reviewing robots or navigation systems in orthopedics can be found in the literature. Most of them are focused on a meta-analysis or reviewing clinical outcomes and user studies [2; 19; 20; 21; 22], a specific field like MIS [5], or a specific feature like haptic feedback [23]. Instead of those, this paper presents a historical review of the robotic systems and navigation techniques that exist and have ever existed in the field of orthopedics, especially on those systems still commercially available at present.