Comparative Analysis Of Six Degrees Of Freedom Kinematics Of The Knee Joint In Healthy Subjects During Uphill,Downhill And Level Walking

Background:Knee joint,as the largest and most complex joint in human body,bears the huge load of body weight and sports,which makes knee joint injury very common.However,due to the current clinical diagnosis of knee joint injuries mainly rely on subjective diagnosis,manual examination and imaging,the diagnosis of some knee joint injuries,such as anterior and posterior cruciate ligament injury or fracture,still have missed diagnosis or misdiagnosis.With the update and progress of biomechanics technology,it is found that the analysis of knee kinematics can provide an important theoretical basis for the assessment of knee injuries in dynamic activity state,and may become one of the important diagnostic methods of knee injuries,laying an important foundation for the effective clinical diagnosis of knee injuries.Walking is the main activity in our daily life,and the analysis of knee joint kinematics in walking is also widely concerned by scholars.In order to explore the movement mode and injury mechanism of the knee joint,many scholars have carried out different kinematics research on the knee joint.Yet the study found that only the ground walk knee kinematics assessment is not enough to reflect the stability of the knee joint function and potential damage,and complicated movements,such as sprints,landing impact,jump action potential damage is easy to find,but at the same time the risk of further damage to the hop,up and down the stairs in clinical use have a lot of inconvenience.Besides,there were not enough research about study of six degrees of freedom in different slops walking.Uphill and downhill walking can generate backward or forward shear forces on the knee due to gravity,which can provide more kinematic information than the kinematic analysis of the knee during level walking,which may provide important method support for the assessment of clinical knee injury.Objective:By considering the clinical safety and ease of implementation,our experiments were using infrared digital navigation of knee joint three dimensions motion capture system,for healthy people uphill and downhill walking peacefully knee kinematics capture under three conditions,and obtain the conditions for the above three kinds of six degree-of-freedom knee kinematics characteristics of comparative analysis.Our study aims to explore the changes of six degrees of freedom in uphill,downhill and level walking in healthy subjects,which can become one of the methods for clinical evaluation of the knee joint and provide important basic data support for the uphill and downhill gait of patients in the future.Methods:A portable motion capture system(Opti Knee,Innomotion,Shanghai,China)for three-dimensional digital navigation analysis system of knee joint based on infrared stereo measurement was used.24 normal subjects,a total of 48 cases of normal knee on level,uphill and downhill walking gait analysis,draw a six degrees of freedom,and the uphill,downhill and horizontal walk the activities of the six degrees of freedom and the gait cycle mean statistical analysis,using the single factor analysis of variance method for statistical analysis.Results:Through statistical analysis,the following results were obtained in this experiment: 1)through the kinematics comparison of six degrees of freedom of knee joints with different phases in the walking gait cycle of uphill,downhill and level,it found significant differences in flexion-extension and internal-external during the whole gait cycle.The differences of adduction-abduction occurred in stance phase and mid-swing phase.The differences of anterior-posterior translation occurred in early stance phase and whole swing phase.There were no significant differences found in proximal-distal translation and lateral-medial translation during different slopes walking.2)By comparing the average range of range of motion,it can be known that the range of flexion-extension increase of 4.2 ° when downhill contrast with level walking,uphill walking decreased 4.5 ° compared with level walking.The range of motion in flexion-extension has significant differences among level,uphill and downhill walking(P<0.05).The range of adduction-abduction was reduced 0.9 ° in uphill walking and increased 0.8 ° in downhill walking.There was a significant difference in the range of motion in adduction-abduction.Internal-external rotation range was decreased 3.1 ° when uphill walking compared with level walking,while downhill walking increased 1.1 °,and there was a significant differences between uphill and level(P<0.05);and uphill compared with downhill walking(P<0.05).From the range of motion of translation,when the compared with level walking,the uphill walking decreased by 1.4mm on average in anterior-posterior translation,while the downhill walking increased by 1.6mm.And there was no significant difference between proximal-distal translation and lateral-medial translation during different slopes walking(P>0.05).Conclusion:In this study,a three-dimensional joint dynamic assessment system based on infrared navigation technology was used.Through the analysis of the six degrees of freedom data of this experiment,we concluded that healthy people uphill,downhill,and the level walking six degrees of freedom of the data,the data has certain stability.Nowadays the research on uphill and downhill walking did not find out any research about six degree of freedom,especially the translation between the femur and tibia.Our research can lay a foundation for future studies on the gait of patients with knee joint injury on uphill and downhill walking,to provide more reference for knee joint diagnosis and assessment information.