Knee injuries are one of the most common injuries that can befall sportspeople or those that simply enjoy an active lifestyle. Such injuries can lay up patients for weeks while they wait for the joints to regain their full function. Although the time it takes for the knee to heal is directly related to how well it responds to the chosen treatment, it can be difficult for an orthopedic doctor to evaluate the healing process and for the patients themselves to know what progress they are making. Researchers have now developed a new type of bandage that features integrated sensors to monitor a knee's range of movement over time to let patients know how they are progressing and let doctors know it they need to adapt the treatment.

The new bandage, developed by researchers from the Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, comprises a bracket that incorporates special sensors that measure and record the joint's range of movement, as well as determining to what degree it rotates and what forces are acting upon it. The sensors used in the bandage include angular measurement systems based on magnetic principles, and acceleration and rate-of-rotation sensors.

The sensors observe movements and record data continuously, allowing doctors to determine exactly how patients are moving their knee and observe how the knee's range of movement changes over time. Using software that evaluates the data and presents it in an easy-to-understand format, doctors can recognize trends and, if necessary, adjust the treatment. The researchers say the various fittings for the sensor systems have been designed so they don't restrict freedom of movement in any way, so the patients do not even notice their knee is being monitored.

Dipl.-Ing. Bernhard Kleiner of Fraunhofer IPA says that the new bandage can give patients a psychological boost by highlighting every little improvement in knee mobility, even though they may not feel they are getting any better.

"We would like to apply the measurement of human kinematics to other parts of the body in future," says Kleiner. The Fraunhofer researchers have already set their sights on the shoulder and hip joints, but with their movement about all three axes, these joints pose extra difficulties. To overcome this, the engineers are looking at coupling 3D sensor systems with special software.

The mobile joint monitoring bandage developed at Fraunhofer will be demonstrated at the MEDTEC Europe trade show, which runs from March 22-24, 2011, in Stuttgart, Germany.