title: Dynamic EMG of peroneus longus in hemiplegic children with equinovarus.
abstract: OBJECTIVE
  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 20μV. 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Service de neurologie pédiatrique, CHU La Timone-Enfants, 13385 Marseille, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France. Electronic address: christophe.boulay@ap-hm.fr.
authors.forename: C
authors.initials: C
authors.lastname: Boulay
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: M
authors.initials: M
authors.lastname: Jacquemier
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: V
authors.initials: V
authors.lastname: Pomero
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: E
authors.initials: E
authors.lastname: Castanier
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: G
authors.initials: G
authors.lastname: Authier
authors.affiliation: Service de neurologie pédiatrique, CHU La Timone-Enfants, 13385 Marseille, France.
authors.forename: B
authors.initials: B
authors.lastname: Chabrol
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: G
authors.initials: G
authors.lastname: Bollini
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: J-L
authors.initials: JL
authors.lastname: Jouve
authors.affiliation: Laboratoire de la marche, service de chirurgie orthopédique pédiatrique, CHU La Timone-Enfants, 264, rue Saint-Pierre, 13385 Marseille cedex 05, France; Institut des sciences du mouvement, Aix-Marseille université, UMR CNRS 6233, 13385 Marseille, France.
authors.forename: E
authors.initials: E
authors.lastname: Viehweger
mesh_terms: D002547:Cerebral Palsy / Q000150:complications / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D003025:Clubfoot / Q000150:complications / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology; D006429:Hemiplegia / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology*; D013308:Streptonigrin; D016138:Walking / Q000502:physiology
chemical_list: C079133:retrostatin; D013308:Streptonigrin
keywords: Cerebral palsy; Equinus; Hemiplegia; Hémiplégie; Paralysie cérébrale; Peroneus longus; Équin