A novel device for improving marker placement accuracy

Abstract

Background Repeatability of marker placement has been acknowledged as a major factor affecting the reliability of multi-segment foot models. A novel device is proposed that is intended to reduce marker placement error and its effect on the reliability of inter-segmental foot kinematic data is investigated. Method The novel device was tested on eight healthy subjects. Landmarks were identified and indicated on the subject's foot at the start of testing using pen, and these points were used to guide placement. Markers were twice attached by a podiatrist using a standard approach, and twice by a researcher who used the novel device. Replacement accuracy and the kinematic reliability of the foot model data for both techniques were analysed. Results The mean marker placement variability using the novel device placement device was 1.1 mm (SD 0.28) compared to 1.4 mm (SD 0.23) when using standard placement techniques. Results suggest that these reductions in placement error tended to improve the overall reliability of the multi-segment data from the foot model. Discussion The novel device is a simple and inexpensive tool for improving the placement consistency of skin-mounted markers.