Article

Localization of the hip joint center (HJC) is essential in computation of gait
data. EOS low dose biplanar X-rays have been shown to be a good reference in
evaluating various methods of HJC localization in adults. The aim is to evaluate
predictive and functional techniques for HJC localization in typically developing
(TD) and cerebral palsy (CP) children, using EOS as an image based reference.
Eleven TD and 17 CP children underwent 3D gait analysis. Six HJC localization
methods were evaluated in each group bilaterally: 3 predictive (Plug in Gait,
Bell and Harrington) and 3 functional methods based on the star arc technique
(symmetrical center of rotation estimate, center transformation technique and
geometrical sphere fitting). All children then underwent EOS low dose biplanar
radiographs. Pelvis, lower limbs and their corresponding external markers were
reconstructed in 3D. The center of the femoral head was considered as the
reference (HJCEOS). Euclidean distances between HJCs estimated by each of the 6
methods and the HJCEOS were calculated; distances were shown to be lower in
predictive compared to functional methods (p<0.0001). Contrarily to findings in
adults, functional methods were shown to be less accurate than predictive methods
in TD and CP children, which could be mainly due to the shorter thigh segment in
children. Harrington method was shown to be the most accurate in the prediction
of HJC (mean error approximately 18mm, SD=9mm) and quasi-equivalent to the Bell
method. The bias for each method was quantified, allowing its correction for an
improved HJC estimation.
CI - Copyright (c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS