Article

In hemiplegic children the appearance of equinovarus is correlated
with premature electromyography (EMG) activity of the gastrocnemius medialis (GM)
prior to initial contact. The goal was to analyze the onset of EMG activation in
the GM and, more particularly, the peroneus longus (PL) in cases of equinovarus:
is PL activity likewise premature ? METHODS: As 15 hemiplegic
children (age 5 years+/-1.5) with equinovarus walked, their PL and GM EMG
activity was being recorded.
The latter was normalized in terms of gait cycle
percentage (0-100%) and detected through semi-automatic selection with activation
threshold set at 20muV. A paired t-test compared activation onset of the PL
versus the GM muscles. RESULTS: As regards the healthy limb, activity onset of
the GM (+14.55%) and the PL
(+19.2%) muscles occurred only during the ST. In
cases of equinovarus, activation of the GM (-5.2%) and the PL (-6.1%) occurred
during the SW and was premature. For each muscle, comparison between the healthy
and the hemiplegic side was highly significant (P<0.001).
CONCLUSION: Premature
PL and GM EMG activity preceding initial contact corresponds not to a disorder
secondary to imbalance but rather, more probably, to motor command dysfunction.
While the PL consequently contributes to equinus deformity, its possible role in
varus genesis is less evident. EMG study needs to be completed by comparing PL
and tibialis posterior strength while taking foot bone morphology into full account.
CI - Copyright (c) 2014 Elsevier Masson SAS. All rights reserved.
- Enfant

Langue : ANGLAIS ; FRANCAIS