Intraoperative Sensor to Comprehensively Measure Ligament Engagement During Knee Arthroplasty

Project Summary/Abstract There is a critical unmet need for a device that directly measures ligament engagement in the operating room. Accordingly, the overall objective of this NIH Phase I STTR project is to integrate a handheld ligament tensiometer into a custom joint distractor and test its ability to quantify metrics of ligament engagement of interest to arthroplasty surgeons. The rationale for this project is that direct, intraoperative measurements of ligament engagement that seamlessly fit into a standard clinical workflow will enhance surgeon’s ability to properly balance ligaments during total knee arthroplasty. The overall objective will be achieved by completing the following specific aims. The first aim is to integrate a handheld ligament tensiometer into an intraoperative joint distractor to create an innovative distraction tensiometer. Both the ligament tension measurements, and joint distraction displacements and tensions of this integrated device will be calibrated and then evaluated against gold-standard measurements from a custom mechanical testing fixture. The milestone of success for the first aim is that the errors in ligament tension will be less than 20% and errors in joint distraction displacement/force will be less than 5% relative to gold-standard measurements. The second aim is to evaluate the ability of the distraction tensiometer to quantify ligament engagement in situ. To evaluate the ability of this device to measure ligament engagement, 2 surgical collaborators and 3 orthopedic fellows/residents will use the distraction tensiometer to directly quantify engagement of the medial and lateral collateral ligaments in 10 human cadaveric knees. The errors between measurements from the distraction tensiometer and the gold-standard measurements from the University of Wisconsin–Madison’s robotic testing system will be computed. The milestone of success for the second aim is that the errors in ligament engagement displacement, engagement tension, and stiffness will be less than 5%, 10%, and 10% respectively, from the gold-standard measurements. The contribution of this research will be significant because the distraction tensiometer has the potential to redefine how surgeons set the engagements of ligaments during total knee arthroplasty that will (1) benefit hundreds of thousands of patients per year, (2) maximize health system reimbursements, and (3) minimize the economic burden of revision surgeries. The proposed research is innovative because it will enable, for the first time, direct measurements of ligament engagement during knee arthroplasty. Without such a device, surgeons will remain limited in their ability to identify and correct ligaments with improper engagement that will in-turn limit the efficacy of total knee arthroplasty to improve patient quality of life and alleviate the large economic burden that revision procedures place on the healthcare system.