Analyzing 3D Knee Kinematics Using Accelerometers, Gyroscopes and Magnetometers

Knee kinematics has been investigated to diagnose subjects with injured anterior cruciate ligament (ACL). Dejnabadi et al. presented a kinematics analysis method using accelerometers and gyroscopes. Although it can analyze the knee kinematics without accumulation of errors, it estimates only knee flexion/extension angle. Thus, this paper proposed a new method that can estimate all knee joint angles, flexion/extension, internal/external rotation, and varus/valgus angles. It is enabled by introducing earth magnetisms into Dejnabadi's method. The proposed method was validated by applying the proposed method a subject. And, the estimated angles were numerically evaluated by comparing the results with optical motion system.