Problem Statement
This project aims to use a robotic arm to support the placement of pins in a Total Knee Arthroplasty. The goal will be to align the cutting guides according to the planned cuts necessary to place an implant on the bone. The surgical plan will use the known shape models of bones to plan the positions of joint replacement implants. To replace invasive IR trackers, a non-invasive camera will be used to scan the bone surface and register the preoperative model to the actual bone. The robotic arm will drive the alignment of the drilling tool and drill holes in the tibia and femur to place the guiding pins. Given that the body can move during the drilling of the pin holes and the base of the arm may not be completely rigid, compensating for that motion in real time should be performed. The system will guide the placement of guide pins which serve to mount the cutting guides.
Use Case
An orthopedic surgeon needs to perform a total knee replacement (arthroplasty) on a patient to ease pain caused by arthritis. The physician will begin the surgery by orienting the patient on their back. The knee being operated on is in full flexion and facing upwards, and then clears out the skin and fat, exposing the knee joint.
The surgeon will bring the robotic system on a cart so that the knee is in the field of view of the camera on the robot arm. The robot arm has a surgical drill as its end effector. With the knee exposed, our robotic system would use the camera to sense a point cloud of the patient’s knee without requiring drilling invasive IR trackers. This is then used to localize the knee in 3-dimensional space, fitting the 3D geometry from a preoperative generic bone model to the patient’s knee on the operating table. This registration process is done in real time, allowing it to track and adjust to any relative motion, ensuring continuous and precise localization throughout the surgery.
The system then decides the desired location of the implant/cutting guide on the patient based on the pre-stored surgical plan. A cutting trajectory is then generated, which a robotic arm will follow to drill holes in the femur and tibia to place the surgical cutting guides. The surgeon then starts the robotic arm, which begins to track the trajectory autonomously, move to the drilling site, and drill holes according to the surgical plan.
The robot arm detects and compensates for movements in the patient’s knee that occur due to the applied forces, maintaining the surgical plan. Furthermore, the doctor is provided with visual feedback on a monitor and an emergency stop. Once the robot arm has completed the planned trajectory, it stops and returns to the home position, allowing the doctor to remove the arm from the surgical area and make cuts in the bone.
To better illustrate how the entire system operates in the operating room environment, we have developed a new figure that shows the spatial arrangement of our robotic system. In this figure, the patient lies supine with the target knee exposed and facing up. The main robot arm stands beside the patient, and its end effector—fitted with the surgical drill—is positioned over the surgical site. The onboard camera integrated into the robot’s wrist segment captures the patient’s knee surface while the surgeon, standing nearby, interacts with a user interface and monitors the robot’s progress and safety cues.
By examining this figure, viewers can easily understand how the “Perception Subsystem” (the camera and sensing apparatus) and the “Manipulation Subsystem” (the robotic arm and drill end effector) work together. The Perception Subsystem first scans the knee, localizing anatomical structures without the need for invasive markers. Simultaneously, the Manipulation Subsystem precisely executes the drilling plan derived from the patient-specific anatomical model and the pre-stored surgical plan.
System Features
Non-Invasive
With our vison-based bone registration method, the invasive and bulky IR tracker are replaced. This approach minimizes patient discomfort, reduces the risk of potential complications, and enhances the overall surgical experience.
AI-powered
Leverages artificial intelligence (AI) to optimize implant positioning and robotic arm movements throughout the surgical procedure. AI algorithms analyze patient-specific data and surgical planning parameters, enabling precise implant placement, reduced surgical error, and improved patient outcomes.
Auto Drilling
Features an automated drilling mechanism that ensures consistent and accurate implant insertion. This automation streamlines the surgical process, minimizes human error, and promotes optimal implant alignment and stability.
Implant Compatibility
The Tekkneeca system continues to evolve and expand compatibility with our total, partial, and revision knee systems.