Experimental Measurement of Flexion-Extension in Normal and Osteoarthritic Knee during Sit-to-Stand Movement

The aim of this paper is to compare the range of motion of the sit-to-stand (STS) movement angles for the both knees: osteoarthritic (OA) left knee and healthy right knee, for seven subjects who performed an experimental test consisting of STS cycles on a chair. The acquisition system consists of two electro-goniometers, one for each leg, for making possible the simultaneously reading of data during experiments. The angular amplitudes of human knee flexion-extension during the STS cycles are obtained as data files. For each knee of all subjects were selected 8 consecutive cycles which were normalized by interpolation with cubic Spline functions, using MATLAB environment. The final medium STS cycle for both knees is obtained. Finally, statistical analyses are made and the results are presented. The maximum values of the knee angle for both knees of all seven subjects were compared and tested with an unpaired Student t-test, considering α=0.05. The p-values corresponding to this test are calculated using ANOVA. Based on the average anthropometric data the virtual model of a mannequin using SolidWorks software was developed, and then was transferred to ADAMS simulation environment in order to obtain the variation laws of reaction forces in the lower limb joints.