Article

The mechanical characteristics of ankle foot orthoses (AFOs), such as the
stiffness and neutral angle around the ankle and metatarsal-phalangeal (MTP)
joints, are rarely quantified. Paradoxically, it is expected that these
characteristics determine the function of the AFO in pathological gait. Therefore
a device to determine these AFO characteristics named BRUCE was designed based on
multidisciplinary consensus. The design is based on a replicated human leg that
is manually driven and continuously registers joint configuration and force
exerted by the AFO onto the device. From this information, neutral angles and
stiffnesses around the ankle and MTP joints are determined using a linear fit.
The reliability of the stiffnesses and neutral angles was studied by repeatedly
measuring the mechanical characteristics of four different AFOs, and evaluating
the inter-session, intra-session, and inter-observer errors. The reliability
study revealed that ankle and MTP stiffness could be measured with very high
reliability (ICC=0.98-1.00). Ankle and MTP neutral angles showed reasonable
reliability (ICC=0.79-0.92). Measurement error in the neutral angles could mainly
be attributed to the difference in testers. With a fixed tester excellent
reliability was obtained (ICC=0.99-0.99). The results derived using BRUCE can
help to gain insight into the role of the mechanical characteristics of AFOs in
correcting pathological gait. Objective information of AFO characteristics is
expected to lead to a better founded prescription of AFOs, resulting in optimal
functional benefit for the patient.

Langue : ANGLAIS