Short communicationP 174 - Analysis of vertical ground reaction force and vertical centre of mass movement following total hip replacement
Introduction
Usually, ground reaction force (GRF) is produced by two feet: an anterior leg is called as leading leg and other as trailing leg [1]. The aim of this study was to investigate the role of the leading and trailing legs’ force contribution to the control of the centre of mass (COM) descent and ascent in patients following a unilateral total hip replacement (THR) [2,3].
Section snippets
Research question
Do the patients with hip total replacement have different ratios of the leading and trailing legs’ forces from the healthy people during gait?
Methods
Sixteen normal healthy subjects (age 63.4 ± 5.4 year old) and 17 unilateral THR patients (66.9 ± 3.5) were enrolled in the study. The three-dimensional gait data obtained in this study were collected using Vicon® motion system and GRFs were collected using two AMTI® or Kistler® force platforms. Three groups were created for statistical analysis, (1) normal subjects, (2) those operated on the left side (op-left) and (3) those operated on the right side (op-right). GRFs were calculated as the
Results
It was observed that in both the normal and op-right groups, the trailing leg was vertically decelerating the COM downward and the leading leg was vertically accelerating the COM upward during gait. The normal group applied 81.97% and the op-right group 82.30% of the vertical GRF, used to decelerate the COM vertically at single stance before initial contact of the contralateral limb. The op-left group presented with a deceleration deficiency of the downward motion of their COM due to less force
Discussion
The deficiency in patient group may be a consequence of pre-surgery gait adaptations, pain or evolving osteoarthritis in the contralateral limb. The differences between healthy and patient groups were found in this study but the mechanism for the difference needs to be interpreted using biomechanics, which is a potentially big job in near future.
References (3)
Controlling the Motion of the Centre of Mass in Cerebral Palsy
(2014)