Technologies

These smart orthopedic screws allow physicians to noninvasively detect and monitor the health of bone implants, potentially preventing infection and implant loosening over time. In the United States, musculoskeletal injuries affect over 28 million patients annually – at least two million of which require fracture fixation surgery. These surgeries typically involve bone implants that are held in place by orthopedic screws, ensuring their functional position is held in place over time. In the cases of surgical fracture fixation, it’s important to monitor the fixation health of the implants since refracture, malunion, infection, and loosening occurs in almost 10% of all orthopedic and dental implants due to mechanical strain. While optical-based options for measuring implant strain are currently available, such as Moire pattern analysis and photoelastic polarimetry, these approaches are insufficient for measuring through tissue due to limitations imposed by the background, spectral distortion, and resolution. Clemson University researchers have developed “smart” orthopedic screws that incorporate x-ray excitable materials so detection through tissue is possible. This approach enables noninvasive monitoring and detection of implant strain so preventative measures can be taken to limit patient stress.

Technical Summary

These tension-indicating screws provide physicians with the ability to “see” bone implants noninvasively. Physicians can gauge the fixation health of implants by sensing the mechanical strain indicated by x-ray excited materials in the orthopedic screws. By incorporating biocompatible luminescent materials – such as fluorescent, phosphorescent, red and near infrared phosphorescent dyes – detection of the screws through living tissue is achievable. This method allows for many types of indicator dyes to be used in the screws, making the method accessible and simple to implement. The dyes can be detected via near infrared laser or x-ray, allowing physicians to gauge implant strain and potential loosening or infection safely and accurately.