The effect of static standing posture on dynamic walking kinematics: comparison of a thigh wand versus a patella marker.

A thigh wand affixed to the lateral and distal parts of the thigh has typically been used as part of the 3-D computerized gait analysis marker set and model to assess hip rotation in walking. A marker placed on the patella has been proposed as an alternative. The purpose of this study was two-fold. First, determine if the static standing hip posture affected kinematic gait data of hip rotation. Second, determine which marker within the configuration, (a thigh wand or patella marker) performed more consistently with the variation in static hip position. Ten adult subjects participated in this study. Three static trials were captured for each subject (typical hip rotation, internal hip rotation, external hip rotation) and processed twice; once using the thigh wand and a second time using the patella marker. The subject then walked typically with one trial randomly selected for analysis. When using a thigh wand, mean dynamic hip rotation determined in stance phase was significantly different (7 degrees internal to 17 degrees external) with the three static hip rotation variations. For the patella marker, there was no significant difference in gait hip rotation (7 degrees external) with the three static hip rotation postures. In conclusion, because gait hip rotation was more consistently determined with changes in standing static hip rotation postures, it is recommended that a marker on the patella be used in the conventional gait marker set in lieu of a thigh wand.