Researchers at Binghamton University are developing innovative “smart knee” implant technology that could allow patients to monitor stress on their artificial knee joints using a smartphone application. This advancement could significantly improve outcomes after knee replacement surgery by helping patients and clinicians identify activities that place excessive strain on the implant and may lead to complications.
Rising Demand for Knee Replacement Surgeries
According to the American College of Rheumatology, nearly 800,000 total knee replacement procedures are performed annually in the United States. Moreover, experts expect this number to rise sharply by 2030, driven by an ageing population and the increasing incidence of sports-related injuries.
Despite the success of these procedures, implant longevity remains a concern. In fact, approximately one in five patients experiences loosening or imbalance in the artificial joint, which can eventually require revision surgery.
Smart Knee Technology to Detect Joint Stress
To address this issue, Professor Shahrzad “Sherry” Towfighian from the Department of Mechanical Engineering at Binghamton University’s Thomas J. Watson College of Engineering and Applied Science has been developing smart knee technology for nearly a decade.
Currently, knee implants do not contain sensors capable of detecting mechanical stress or early signs of implant failure. Consequently, problems often remain unnoticed until symptoms become severe.
Towfighian explained that embedded sensors capable of measuring joint loads noninvasively could enable clinicians to detect abnormal stress patterns much earlier. Early detection would allow physicians to adjust treatment strategies and potentially prevent implant failure.
Self-Powered Sensors Harvest Energy from Movement
As reported by medicalxpress, the research team is developing self-powered sensors that rely on piezoelectric and triboelectric transducers. These technologies convert the knee’s natural movements into small amounts of electrical energy.
Specifically, triboelectric generation produces energy when two surfaces come into contact or slide against each other, while piezoelectric generation generates electricity from vibration and pressure. By combining both technologies, researchers can create sensors that measure joint load while simultaneously generating power.
Because the energy output directly corresponds to the mechanical load applied to the knee, the device functions both as an energy harvester and a load sensor.
Ongoing Research and Future Testing
Recent studies published in Nano Energy, Sensors, and IEEE/ASME Transactions on Mechatronics by Towfighian and doctoral researchers Mahmood Chahari, Osama Abdalla, and Elham Mahmoudi have focused on identifying optimal materials and designs for these energy-harvesting sensors.
The research also involves collaboration with experts from Stony Brook University and Western University in London, Canada. Researchers compared the sensor’s performance using a joint simulator capable of replicating the six degrees of freedom in the knee joint.
Next, the team plans to seal the device and conduct testing on cadaveric knee models to evaluate biocompatibility and sensor accuracy. If successful, smart knee implants could transform post-surgical monitoring and long-term implant management in orthopaedic care.