title: Electromyographic and magnetic resonance imaging evaluations of individuals with patellofemoral pain syndrome.
abstract: OBJECTIVE
  To analyze the electrical activity of the vastus medialis obliquus (VMO), vastus lateralis longus (VLL) and vastus lateralis obliquus (VLO) muscles of individuals with patellofemoral pain syndrome (PFPS) during maximum voluntary isometric contraction (MVIC) of lower leg extension with the knee at 30 degrees; to assess pain using a visual analogue scale (VAS); and to assess patellar positioning using magnetic resonance imaging (MRI).
  
  
  METHODS
  Twelve women with PFPS and 12 clinically normal women were evaluated. They performed five MVICs of lower leg extension at 30 degrees for electromyographic (EMG) analysis. Using MRI, the sulcus angle (SA), congruence angle (CA), patellar tilt angle (PTA) and patellar displacement (PD) were obtained. The following statistical tests were used: analysis of variance (ANOVA) for repeated measurements to assess EMGs; Mann-Whitney U test to analyze MRIs; Pearson's (r) correlation test between EMGs and MRIs; and one-way ANOVA to evaluate pain (p < or = 0.05).
  
  
  RESULTS
  In the PFPS group, there was greater electrical activity in the VLL than in the VMO. In both groups, there was greater electrical activity in the VMO and VLL than in the VLO. In the PFPS group, the MRI showed higher SA and lower CA values, and there was a negative correlation between the VMO and the PTA.
  
  
  CONCLUSIONS
  The data suggest that, in individuals with PFPS, greater electrical activity in the VLL combined with an increased SA and a decreased CA may contribute to patellar instability.
authors: Departamento de Fisioterapia, Universidade Federal de São Carlos, São Carlos, SP, Brasil. alesouza_28@hotmail.com
authors: Alessandra de Castro Souza
authors: Ade C
authors: Ribeiro
authors: Débora B
authors: DB
authors: Grossi
authors: Bernd
authors: B
authors: Foerster
authors: Cecília
authors: C
authors: Candolo
authors: Vanessa
authors: V
authors: Monteiro-Pedro
mesh_terms: D004576:Electromyography; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D046788:Patellofemoral Pain Syndrome / Q000175:diagnosis*; D055815:Young Adult