Conformable Microfluidic Force Sensors for Precision Joint Replacement Surgery

Over 2 million THRs are performed annually, with the number constantly increasing due to an increasing lifespan. The patient demographic is also shifting towards the young, and hence implants need to withstand higher stresses and last longer to avoid spiralling into a vicious circle of revision surgery. Precise implant positioning and balancing during surgery is key to prevent eccentric loading and subsequent failure of the implant. Measuring forces passing through the joint is crucial to obtain an optimal, force-balanced position; however, there are currently no technologies that can deliver these readings intraoperatively in real-time and surgeons currently balance the implant based on "feel" and anatomical landmarks. To address this unmet clinical need, our interdisciplinary team of clinical and physical scientists has developed novel microfluidics-based force sensors (patent application WO2022043709A1) that can measure the large loads (>100N) passing through the joint during surgery. Importantly, the sensors are thin and conformable, and we have integrated an array of them within the trial acetabular liners used during hip replacements. This "smart" trial liner is our proposed intraoperative surgical aid that would be used only during surgery to balance and position the implant based on objective readouts of the forces passing through the joint. This proposal involves developing our lab-based prototype along a medical device product development pathway, guided by patient and user inputs, with appropriate quality management and documentation in place, to produce a highly characterised device that undergoes pre-verification testing and cadaver studies in advance of future clinical trials. Aims and Methodology We will develop a PPI impact log to collate inputs from patients who have had a THR and the general public to inform our product development strategy. We will also survey surgeons to guide user and product requirements. Against this backdrop, we will combine the expertise of SK-N s laboratory with those of technical consultants Springboard Pro to complete product development in a quality-controlled and appropriately documented manner, till the pre-verification testing stage. We will have SOPs in place for device fabrication, calibration, characterisation, and will conduct a cadaver trial of the finalised device to test usability for the first-in-human trial. Timelines PPI work will run throughout the 24-month timeline of the project. Regulatory planning and establishing quality-controls supported by Clinical Engineering at CUH is planned for the first 12 months. Product development and characterisation, jointly between VK, SK-N s laboratory and Springboard, will run throughout the project, with the cadaver trial in the final 3 months once pre-verification testing has been completed (Gantt enclosed). Anticipated Impact and Dissemination The main purpose of this proposal is to develop a novel intraoperative surgical aid and facilitate its route to the clinic. Research outputs will include results from the bench top model in the lab and the cadaver trial. This project will significantly de-risk the device s development, and should facilitate further funding to complete the design control stage of development and subsequent first-in-human trials for which we expect to raise funding via further grants or investment into our associated spin-out company ArtioSense Limited.