title: Determination of patellofemoral pain sub-groups and development of a method for predicting treatment outcome using running gait kinematics.
abstract: Not all patients with patellofemoral pain exhibit successful outcomes following exercise therapy. Thus, the ability to identify patellofemoral pain subgroups related to treatment response is important for the development of optimal therapeutic strategies to improve rehabilitation outcomes. The purpose of this study was to use baseline running gait kinematic and clinical outcome variables to classify patellofemoral pain patients on treatment response retrospectively.
  
  
  
  Forty-one individuals with patellofemoral pain that underwent a 6-week exercise intervention program were sub-grouped as treatment Responders (n=28) and Non-responders (n=13) based on self-reported measures of pain and function. Baseline three-dimensional running kinematics, and self-reported measures underwent a linear discriminant analysis of the principal components of the variables to retrospectively classify participants based on treatment response. The significance of the discriminant function was verified with a Wilk's lambda test (α=0.05).
  
  
  
  The model selected 2 gait principal components and had a 78.1% classification accuracy. Overall, Non-responders exhibited greater ankle dorsiflexion, knee abduction and hip flexion during the swing phase and greater ankle inversion during the stance phase, compared to Responders.
  
  
  
  This is the first study to investigate an objective method to use baseline kinematic and self-report outcome variables to classify on patellofemoral pain treatment outcome. This study represents a significant first step towards a method to help clinicians make evidence-informed decisions regarding optimal treatment strategies for patients with patellofemoral pain.
authors: Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: ricky.watari@ucalgary.ca.
authors: Ricky
authors: R
authors: Watari
authors: Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: drjkobsa@ucalgary.ca.
authors: Dylan
authors: D
authors: Kobsar
authors: Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: aphinyom@ucalgary.ca.
authors: Angkoon
authors: A
authors: Phinyomark
authors: Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada; Running Injury Clinic, Calgary, Alberta, Canada. Electronic address: stosis@ucalgary.ca.
authors: Sean
authors: S
authors: Osis
authors: Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada; Faculty of Nursing, University of Calgary, Calgary, Alberta, Canada; Running Injury Clinic, Calgary, Alberta, Canada. Electronic address: rferber@ucalgary.ca.
authors: Reed
authors: R
authors: Ferber
mesh_terms: D000293:Adolescent; D000328:Adult; D000842:Ankle / Q000503:physiopathology; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena; D005081:Exercise Therapy; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D010146:Pain / Q000503:physiopathology*; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D025341:Principal Component Analysis; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D012420:Running / Q000502:physiology*; D016896:Treatment Outcome
keywords: Exercise therapy; Kinematics; Linear discriminant analysis; Patellofemoral pain; Principal component analysis; Running