X-ray Visualized Implanted Sensor for Prosthetic Joint Infection (X-VIS-PJI)

Abstract Our goal is to fabricate and validate a novel pH-indicating sensor which can attach to a hip prosthesis with integrated sensors that can detect and monitor hip infections using standard of care X-ray imaging. Hip replacement surgeries are performed on millions of people worldwide each year. In the United States alone, there were 450,000 total hip arthroplasties performed annually. Most of these surgeries are successful with no complications. However, infections are a leading cause of failure, with an incidence of about ~0.5-2% of total hip replacement surgeries. If detected early, these infections can be treated promptly with antibiotics and surgical debridement. However, mature biofilms usually require implant removal to treat the infection, followed by revision surgery with associated risks of morbidity, mortality, and large cost. Therefore, it’s important to detect post-surgery infections early and monitor the effect of therapies for effective treatment. We have developed novel pH-indicating sensors which can attach to a prosthesis, can measure local infection, and can be quantified using a standard x-ray. This Phase I SBIR will apply these pH-indicating sensors to the femoral- neck of a hip prosthesis and evaluate their utility in a sheep model. Our long term goal is to develop the first device that enables noninvasive local pH measurements using plain radiography. Further development could see the sensor integrated into the implant with further commercialization partnership. Our scientific premise is that acidosis in vivo can be measured noninvasively by conventional radiography using a pH-indicating device fabricated using hydrogels that respond mechanically to the presence of hydrogen ions. Preliminary studies show sufficient response rate, and pH sensitivity in the expected physiological pH range. We will refine the prototype in vitro and human cadaver models, and validate the sensor in vivo function using an animal hip model in sheep. The proposed research is significant because it develops a noninvasive method to detect, monitor, and study infection in situ with the ultimate potential for reducing morbidity, mortality and associated cost from implant infections.