Evaluating the Dynamic Rotational Knee Stability in Knee Joint by Inertial Sensors during Gait Cycle

• Main Authors: Po-Shun Chiu, 邱柏舜
• Other Authors: Cheng-Kung Cheng
• Format: Others
• Language: zh-TW
• Published: 2015
• Online Access: http://ndltd.ncl.edu.tw/handle/98765595743587671779

碩士 === 國立陽明大學 === 生物醫學工程學系 === 103 === Anterior cruciate ligament (ACL) injury is commonly occurred in the non-dominant leg for female. Although reconstructed the ACL, the rotational stability still cannot be restored. For evaluating dynamic rotational stability, current methods are limited due to expensive and need controlled space. In recent year, the inertial measurement unit (IMU) becomes smaller and supports wireless transmission. Therefore, the purpose of this study is to evaluate the correlation between inertial parameters and rotation angle of knee joint. Furthermore, the correlations in dominant/non-dominant leg and different phases during gait cycle are also calculated. A pilot study is performed for determining the difference in calculating rotational angles between the IMU and motion analysis system at rigid bodies. In the method, we recruited ten healthy subjects. The internal-external rotations of knee joint during ambulation were recorded by the motion analysis system. At the same time, the inertial sensors were placed on the thigh and shank to measure the acceleration, angular velocity, and rotation angle of the knee during ambulation. The Pearson correlation coefficient was calculated for understanding the relationship between the inertial variables and rotational angle of knee. In addition, the correlation between maximum inertial variables and maximum rotational angle were also evaluated in stance phase and swing phase. The results showed the differences in determining angle between systems is nearly 3 degrees. In the correlation, lot of inertial variables were mild correlated with rotational angle during gait cycle. Only the difference of sagittal angular velocity in non-dominant leg performed moderate correlation of 0.51. The high correlation of 0.86 are showed between the maximum difference of angular velocity at stance phase and maximum rotational angle. During ambulation, the larger hip range of motion are showed in the non-dominant leg, so the higher thigh rotational velocity may lead to stronger correlation. Furthermore, using the maximum value can get a better correlation to evaluate dynamic rotational stability at stance phase. In conclusion, the inertial parameters can be used to evaluate the rotational instability of knee joint, and the best correlation is showed in the maximum value of inertial variable.