Article

Misalignment of an articulated ankle-foot orthosis joint axis with
the anatomic joint axis may lead to discomfort, alterations in gait, and tissue
damage. Theoretical, two-dimensional models describe the consequences of
misalignments, but cannot capture the three-dimensional behavior of ankle-foot
orthosis use. OBJECTIVES:
The purpose of this project was to develop a model to
describe the effects of ankle-foot orthosis ankle joint misalignment in three
dimensions. STUDY DESIGN: Computational simulation. METHODS: Three-dimensional
scans of a leg and ankle-foot orthosis were incorporated into a link segment
model where the ankle-foot orthosis joint axis could be misaligned with the
anatomic ankle joint axis.
The leg/ankle-foot orthosis interface was modeled as a
network of nodes connected by springs to estimate interface pressure. Motion
between the leg and ankle-foot orthosis was calculated as the ankle joint moved
through a gait cycle. RESULTS: While the three-dimensional model corroborated
predictions of the previously published two-dimensional model that misalignments
in the anterior -posterior direction would result in greater relative motion
compared to misalignments in the proximal -distal direction, it provided greater
insight showing that misalignments have asymmetrical effects. CONCLUSIONS: The
three-dimensional model has been incorporated into a freely available computer
program to assist others in understanding the consequences of joint
misalignments. CLINICAL RELEVANCE: Models and simulations can be used to gain
insight into functioning of systems of interest. We have developed a
three-dimensional model to assess the effect of ankle joint axis misalignments in
ankle-foot orthoses. The model has been incorporated into a freely available
computer program to assist understanding of trainees and others interested in
orthotics.
CI - (c) The International Society for Prosthetics and Orthotics 2014.

Langue : ANGLAIS