PROJECT SUMMARY / ABSTRACT Surgical treatment of joint fractures and dislocations following orthopaedic trauma requires accurate reduction and fixation of the joint space to restore anatomical integrity. In ankle fractures with syndesmotic injuries, inaccuracies in proper realignment are associated with chronic functional impairment, mechanical instability, and increased risk of osteoarthritis. Despite the prevalent role of intraoperative x-ray imaging, uncertainties in spatial reckoning of 3D joint morphology and challenges in hand-eye coordination can result in malreduction rates of up to 39–52% for fellowship- trained orthopedic trauma specialists. This proposal presents a novel system that combines intraoperative imaging, using low-dose CBCT and 3D-2D image registration, with robotic manipulation of the bones to precisely restore joint integrity. The solution offers quantitative analysis of morphology from 3D and 2D intraoperative images and precisely guides a robotic instrument without the need for and the limitations associated with conventional tracked navigation. The following aims develop and evaluate the approach for treatment of syndesmotic injuries in ankle trauma surgery: (Aim 1) Develop a surgical robot for joint reduction. (1a) Design a novel low-profile, radiolucent robotic system to manipulate the distal fibula. (1b) Build the device and develop software to control the robot position and orientation. (1c) Evaluate basic operation in preclinical testing on cadaveric ankle specimens. (Aim 2) Develop image-based planning and confirmation of joint reduction. (2a) Develop automatic 3D image analysis of the tibio-fibulo-talar space from low-dose CBCT and match the dislocated joint to the normal contralateral side. (2b) Develop 3D-2D image registration techniques to register the robot and confirm accurate restoration of the joint space from as few as 2 fluoroscopic views. (2c) Experimentally validate the algorithms on cadaveric ankle specimens. (Aim 3) Perform system integration and end-to-end evaluation of performance. (3a) Integrate the methods from Aims 1 and 2 to guide and confirm robotic manipulation from intraoperative images. (3b) Evaluate the system in cadaver specimens emulating ankle trauma, targeting less than 2 mm and 5° error in joint realignment. (Aim 4) Conduct clinical evaluation of safety and feasibility. Conduct clinical studies to (4a) observe standard of care of ankle fracture surgery and (4b) assess the basic safety and feasibility of the image-based robotic approach in a first in- human clinical trial with 10 patients. Successful completion of the aims will elevate the precision and quality of surgery in an area that currently suffers poor long-term outcomes through use of new methods that are consistent with existing workflows. Success in this research will help to eliminate revision surgeries due to malreduction (a major cost burden) and improve long-term quality of life for >100,000 patients/year. The platform will be developed in a multi-disciplinary consortium of experts in robotics, imaging, and orthopedic surgery and translated to clinical studies. The technology developed will impact trauma surgery beyond ankle repair and would be applicable to surgical treatment of other challenging joint dislocations and long-bone fractures.

PROJECT NARRATIVE Accurate reduction of joint dislocations is challenged by uncertainties in reckoning 3D anatomy from 2D imaging, extended use of fluoroscopy, and high risk of complications that can lead to poor functional outcomes, osteoarthritis, and disability. Proposed work develops an image-guided robotic approach to enable accurate repair of the ankle syndesmosis through automatic 3D planning, precise robotic execution, and intraoperative image-based confirmation. The solution combines modern robotics approaches with intraoperative imaging to satisfy the high technical demands of joint realignment, limit radiation dose to patient and staff, and provide accurate treatment to ultimately improve long-term patient outcomes.