title: Kinematic foot types in youth with equinovarus secondary to hemiplegia.
abstract: BACKGROUND
  Elevated kinematic variability of the foot and ankle segments exists during gait among individuals with equinovarus secondary to hemiplegic cerebral palsy (CP). Clinicians have previously addressed such variability by developing classification schemes to identify subgroups of individuals based on their kinematics.
  
  
  OBJECTIVE
  To identify kinematic subgroups among youth with equinovarus secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during locomotion as inputs for principal component analysis (PCA), and K-means cluster analysis.
  
  
  METHODS
  In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 24 children/adolescents with equinovarus and 20 typically developing children/adolescents.
  
  
  RESULTS
  PCA was used as a data reduction technique on 40 variables. K-means cluster analysis was performed on the first six principal components (PCs) which accounted for 92% of the variance of the dataset. The PCs described the location and plane of involvement in the foot and ankle. Five distinct kinematic subgroups were identified using K-means clustering. Participants with equinovarus presented with variable involvement ranging from primary hindfoot or forefoot deviations to deformtiy that included both segments in multiple planes.
  
  
  CONCLUSIONS
  This study provides further evidence of the variability in foot characteristics associated with equinovarus secondary to hemiplegic CP. These findings would not have been detected using a single segment foot model. The identification of multiple kinematic subgroups with unique foot and ankle characteristics has the potential to improve treatment since similar patients within a subgroup are likely to benefit from the same intervention(s).
authors.affiliation: Midwestern University, Physical Therapy Program, College of Health Sciences, 555 31st Street, Downers Grove, IL, United States; Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States. Electronic address: joekrzak@sbcglobal.net.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Krzak
authors.affiliation: Northwestern University Feinberg School of Medicine, Department of Physical Therapy and Human Movement Sciences, 645 North Michigan Avenue, Chicago, IL, United States.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Corcos
authors.affiliation: National Institutes of Health, Functional & Applied Biomechanics Section, 10 Center Drive, Bethesda, MD, United States.
authors.forename: Diane L
authors.initials: DL
authors.lastname: Damiano
authors.affiliation: Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States.
authors.forename: Adam
authors.initials: A
authors.lastname: Graf
authors.affiliation: University of Chicago, Department of Public Health Sciences, 5841 South Maryland Avenue, Chicago, IL, United States.
authors.forename: Donald
authors.initials: D
authors.lastname: Hedeker
authors.affiliation: Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States; RUSH University Medical Center, Department of Orthopaedic Surgery, College of Medicine, 1611 West Harrison Street, Chicago, IL, United States.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Smith
authors.affiliation: Shriners Hospitals for Children®-Chicago, 2211 North Oak Park Avenue, Chicago, IL, United States; Orthopaedic & Rehabilitation Engineering Center (OREC), Marquette University/Medical College of Wisconsin, 735 North 17th Street, Milwaukee, WI, United States.
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Harris
mesh_terms: D000842:Ankle / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D002547:Cerebral Palsy / Q000503:physiopathology; D002648:Child; D016000:Cluster Analysis; D004863:Equinus Deformity / Q000503:physiopathology*; D005260:Female; D005528:Foot / Q000503:physiopathology*; D006429:Hemiplegia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D025341:Principal Component Analysis
keywords: Cerebral palsy; Equinovarus; Gait; Multi-segmental foot modeling