title: Q-angle static or dynamic measurements, which is the best choice for patellofemoral pain?
abstract: BACKGROUND
  The elevated Q-angle seems to be one of the most suggested factors contributing to patellofemoral pain. Females with patellofemoral pain are often evaluated through static clinical tests in clinical practice. However, the adaptations seem to appear more frequently in dynamic conditions. Performing static vs. dynamic evaluations of widely used measures would add to the knowledge in this area. Therefore, the aim of this study was to determine the reliability and discriminatory capability of three Q-angle measurements: a static clinical test, peak dynamic knee valgus during stair ascent and a static measurement using a three-dimensional system.
  
  
  METHODS
  Twenty-nine females with patellofemoral pain and twenty-five pain-free females underwent clinical Q-angle measurement and static and dynamic knee valgus measurements during stair ascent, using a three-dimensional system. All measurements were obtained and comparisons between groups, reliability and discriminatory capability were calculated.
  
  
  RESULTS
  Peak dynamic knee valgus was found to be greater in the patellofemoral pain group. On the other hand, no significant effects were found for static knee valgus or clinical Q-angle measurements between groups. The dynamic variable demonstrated the best discriminatory capability. Low values of reliability were found for clinical Q-angle, in contrast to the high values found for the three-dimensional system measurements.
  
  
  CONCLUSIONS
  Based on our findings, avoiding or correcting dynamic knee valgus during stair ascent may be an important component of rehabilitation programs in females with patellofemoral pain who demonstrate excessive dynamic knee valgus. Q-angle static measurements were not different between groups and presented poor values of discriminatory capability.
authors.affiliation: University of São Paulo State, School of Science and Technology, Physical Therapy Department, Presidente Prudente, Brazil.
authors.forename: Danilo de Oliveira
authors.initials: Dde O
authors.lastname: Silva
authors.affiliation: University of São Paulo State, School of Science and Technology, Physical Therapy Department, Presidente Prudente, Brazil.
authors.forename: Ronaldo Valdir
authors.initials: RV
authors.lastname: Briani
authors.affiliation: University of São Paulo State, School of Science and Technology, Physical Therapy Department, Presidente Prudente, Brazil.
authors.forename: Marcella Ferraz
authors.initials: MF
authors.lastname: Pazzinatto
authors.affiliation: State University of West Parana, Physical Therapy Department, Cascavel-PR, Brazil.
authors.forename: Ana Valéria
authors.initials: AV
authors.lastname: Gonçalves
authors.affiliation: University of São Paulo, Post-graduation Program Interunits Bioengineering EESC/FMRP/IQSC-USP, São Carlos, Brazil.
authors.forename: Deisi
authors.initials: D
authors.lastname: Ferrari
authors.affiliation: State University of West Parana, Physical Therapy Department, Cascavel-PR, Brazil.
authors.forename: Fernando Amâncio
authors.initials: FA
authors.lastname: Aragão
authors.affiliation: University of São Paulo State, School of Science and Technology, Physical Therapy Department, Presidente Prudente, Brazil. Electronic address: micolis@fct.unesp.br.
authors.forename: Fábio Mícolis
authors.initials: FM
authors.lastname: de Azevedo
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000473:pathology*; D008297:Male; D009068:Movement; D010146:Pain; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000175:diagnosis*; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Anterior knee pain; Kinematic; Lateral patellar maltracking; Patellofemoral joint; Quadriceps angle (Q-angle)