Article

Accurate calibration of the medio-lateral axis of the femur is crucial for
clinical decision making based on gait analysis. This study proposes a protocol
utilizing biplanar radiographs to provide a reference medio-lateral axis based on
the anatomy of the femur.
The biplanar radiographs allowed
3D modelling of the
bones of the lower limbs and the markers used for motion capture, in the standing
posture. A comprehensive analysis was performed and results from biplanar
radiographs were reliable for 3D marker localization (+/-0.35mm) and for 3D
localization of the anatomical landmarks (+/-1mm), leading to a precision of 1
degrees for the orientation of the condylar axis of the femur and a 95%
confidence interval of +/-3 degrees after registration with motion capture data.
The anatomical condylar axis was compared to a conventional, marker-based, axis
and three functional calibration techniques (axis transformation, geometric axis
fit and DynaKAD). Results for the conventional method show an average difference
with the condylar axis of 15 degrees (SD: 6 degrees ). Results indicate DynaKAD
functional axis was the closest to the anatomical condylar axis, mean: 1 degrees
(SD: 5 degrees ) when applied to passive knee flexion movement. However, the
range of the results exceeded 15 degrees for all methods. Hence, the use of
biplanar radiographs, or an alternative imaging technique, may be required to
locate the medio-lateral axis of the femur reliably prior to clinical decision
making for femur derotational osteotomies.
CI - Copyright (c) 2016 Elsevier B.V. All rights reserved.

Langue : ANGLAIS