Validity and comparisons of tibiofemoral orientations and displacement using a femoral tracking device during early to mid stance of walking

First, this study compares tibiofemoral motion during walking using a new femoral tracking device (FTD) and bone mounted markers in a single subject (n=1). The results suggest errors of <3° in tibiofemoral angles using the FTD method over the first 85% of stance. Second, this study compares tibiofemoral angles and displacement during walking using the FTD method and a modified Helen Hayes method to track the femur in 13 subjects (n=13). The results suggest similar tibiofemoral angles in the sagittal and frontal planes using the two methods (average root mean square (RMS) differences <3.6±1.5°), and a large decrease in the transverse plane angles (average RMS DIFFERENCES=6.5±1.9°) and estimates of tibiofemoral displacement (P<0.05) using the FTD method. The FTD method presents a practical alternative to recording tibiofemoral transverse plane angles and displacement over the first 85% of stance.