Validity and comparisons of tibiofernoral 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 +/- 1.5degrees), and a large decrease in the transverse plane angles (average RMS differences = 6.5 +/- 1.9degrees) 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. (C) 2003 Elsevier B.V. All rights reserved.