Wearable Smart Patch Sensors for Monitoring Knee Laxity

Inhalt:
This paper presents a fully innovative wearable sensor patch for diagnosing and assessing anterior cruciate ligament injury and its healing process. Currently, measurement methods are bulky, interfere with knee movements, and the results do highly depend on the experience of the examiner. To overcome the limitations of the existing systems in this paper we present a compact and ergonomic sensor patch, which consists of a capacitive strain gauge sensorwith signal conditioning electronics, power supply, and data transmission interface. To simplify its use for clinicians it can be powered and transmit data wirelessly. Low-power software and hardware design guarantee the use of the device for several days without re- charging. The material and the design are conceived to allow rapid prototyping and patient customization of the sensor. The functionality of the sensor patch was first tested in the laboratory with a knee simulator. Afterwards, to prove the functionality and reliability of the developed sensor system in a real-case scenario, a preliminary pre-clinical analysis was made with a healthy human volunteer, and the results were compared to reference data obtained from a knee simulator. The newly developed system is the first step towards the development of compact devices that can continuously monitor the healing process of a knee after a ligament injury.