title: Simulated Ankle Equinus Affects Knee Kinematics During Gait.
abstract: BACKGROUND
  It is critical to distinguish gait compensations from true abnormalities when planning interventions to improve gait in individuals with neuromuscular disorders.
  
  
  OBJECTIVE
  The aim of this study was to determine the effect of isolated ankle equinus on knee kinematics during the initial contact phase of gait.
  
  
  METHODS
  Ten healthy subjects (29 + 4.3 years) participated, and testing occurred in a motion analysis laboratory. This cross-sectional study investigated five gait conditions in each subject: shoe alone, shoe with unilateral ankle foot orthosis locked at neutral, 10°, 20°, and 30° of fixed ankle plantar flexion. Gait kinematics were recorded and calculated with 3D motion analysis. The difference between the shoe and each brace condition was analyzed by repeated-measures ANOVA. The primary outcome was knee flexion at initial contact.
  
  
  RESULTS
  With greater than 10° simulated ankle equinus, the primary gait compensation pattern was increased knee flexion at initial contact. A significant degree of knee flexion occurred ranging from 7° to 22°.
  
  
  CONCLUSIONS
  Our data suggests that observed knee flexion at initial contact may be a compensation pattern in individuals with >10° ankle equinus. However, in individuals with ≤10° ankle equinus, observed knee flexion may represent a true gait deviation. This has clinical significance in the realm of cerebral palsy for treatment planning to improve gait.
authors: Pediatric Rehabilitation, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA ; Leon Root Motion Analysis Laboratory, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors: Lisa C
authors: LC
authors: Drefus
authors: Leon Root Motion Analysis Laboratory, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors: Jocelyn F
authors: JF
authors: Hafer
authors: Leon Root Motion Analysis Laboratory, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA ; Pediatric Orthopedic Surgery, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021 USA.
authors: David M
authors: DM
authors: Scher
keywords: cerebral palsy; equinus; gait; gait compensations; knee flexion; knee kinematics