Article

Joint kinematics can be calculated by Direct Kinematics (DK), which is used in
most clinical gait laboratories, or Inverse Kinematics (IK), which is mainly used
for musculoskeletal research. In both approaches, joint centre locations are
required to compute joint angles. The hip joint centre (HJC) in DK models can be
estimated using predictive or functional methods, while in IK models can be
obtained by scaling generic models. The aim of the current study was to
systematically investigate the impact of HJC location errors on lower limb joint
kinematics of a clinical population using DK and IK approaches. Subject-specific
kinematic models of eight children with cerebral palsy were built from magnetic
resonance images and used as reference models. HJC was then perturbed in 6mm
steps within a 60mm cubic grid, and kinematic waveforms were calculated for the
reference and perturbed models. HJC perturbations affected only hip and knee
joint kinematics in a DK framework, but all joint angles were affected when using
IK. In the DK model, joint constraints increased the sensitivity of joint
range-of-motion to HJC location errors. Mean joint angle offsets larger than 5
degrees were observed for both approaches (DK and IK), which were larger than
previously reported for healthy adults. In the absence of medical images to
identify the HJC, predictive or functional methods with small errors in
anterior-posterior and medial-lateral directions and scaling procedures
minimizing HJC location errors in the anterior-posterior direction should be
chosen to minimize the impact on joint kinematics.
CI - Copyright (c) 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Langue : ANGLAIS