Knee injuries are extremely common and it can take weeks for a knee that has been damaged to regain full function. The time that it takes for the knee to heal is directly related to the chosen method of treatment however at present doctors typically perform only limited function tests and patients are often left having to rely on their own subjective feelings. Researchers from the Fraunhofer Institute for Manufacturing Engineering and Automation in Stuttgart have now developed a system that can document the knee healing process in detail, allowing doctors to fine tune the appropriate course of treatment.
This is how the novel approach for monitoring the treatment works: special sensors are placed in a bracket that is integrated into the bandage. These register the knee's range of movement over a period of time to determine exactly how patients are moving. A novel piece of software evaluates the data and presents the results in an easy-to-understand format. It sounds pretty simple but it was a tough challenge for the engineers because such angular measurement systems have only ever been used previously in industry. The central question was how to place the sensors onto the human body without inconveniencing the patient. The answer, researchers found, lay in using lightweight materials and miniaturising the sensors, which fall into two categories: angular measurement systems that are based on magnetic principles; and acceleration and rate-of-rotation sensors.
Depending on the injury and treatment, the system not only records the joint's range of movement but can also determine to what degree it rotates and what forces are acting upon it. The sensors continuously observe movements and store data. This allows doctors to observe how the range of movement of the knee changes over time, enabling them to recognise trends and, where necessary, adjust treatment. The various fittings for the sensor systems have been designed by the researchers not to restrict freedom of movement in any way, meaning patients do not even notice that their joint is being monitored.
The researchers would like to apply the measurement of human kinematics to other parts of the body, especially shoulder and hips.
