KNEE MONITOR: Monitoring knee angles and physical activity in daily life using a dual-sensor wearable

Physical activity (PA) can be used as a parameter for the diagnosis, treatment or evaluation of the results of correct health care. The evaluation of physical activity becomes essential after a knee joint surgery as it provides clinicians and physiotherapists with essential information on the patient's motor health and on the effectiveness of rehabilitation. Although the gold standard for the evaluation of subject’s performance during PA is represented by measures taken in gait laboratories, or through force plates and electromyography, recent advances in wearable sensors, especially Inertial Measurements Units (IMU), have opened up a promising future for out-of-the-lab gait analysis. The IMUs are generally composed by an accelerometer, a gyroscope and magnetometer and they are becoming widely used both in scientific and clinical fields. The project on which this thesis is based envisages the construction of a new system for monitoring knee activity in daily life. This new monitoring system consists of two 3D IMUs and an algorithm based on quaternions. The performances of the first prototype of this system have been compared with those of a motion capture laboratory. What emerged is that the new system produced results comparable to those of the gold-standard system in all types of movements performed. Finally, a detailed description of the limits, improvements and future applications of this system was reported