title: The dose-response relationship between lateral foot wedging and the reduction of knee adduction moment.
abstract: BACKGROUND
  Lateral foot wedges represent a biomechanical intervention aimed at reducing medial knee loads. However, the effects of varying wedge amounts on biomechanical variables and orthotic comfort have not been systematically studied. Further, arch height may influence the comfort of laterally wedged devices. Therefore, the primary purpose of this study was to examine the effect of incrementally increasing lateral wedge amounts on knee adduction moment parameters and subjective comfort. The secondary purpose was to relate arch height measures to the comfort of the devices.
  
  
  METHODS
  Twenty-five healthy subjects underwent three-dimensional instrumented gait analysis testing using seven inclinations of lateral wedging (0°, 2°, 4°, 6°, 8°, 10°, 12°). Subjects reported comfort level for each orthotic condition. Arch heights were measured in standing and sitting, and rigidity index and stiffness were calculated.
  
  
  RESULTS
  The knee adduction moment decreased with wedge amounts up to 6°, but more aggressive amounts did not yield additional reductions. Comfort ratings did not change from baseline until wedge amounts exceeded 8°. In addition, arch height measures, arch rigidity index and stiffness did not relate to the comfort of the orthotic device regardless of the wedge amount.
  
  
  CONCLUSIONS
  Knee adduction moment decreased with mild wedge amounts while maintaining comfort. Wedge amounts greater than 6° yielded little additional mechanical benefit and amounts greater than 8° compromised comfort. It appears that 4°-6° of lateral wedging are optimal in regard to desirable biomechanical change and comfort level in healthy individuals.
authors.affiliation: Department of Health and Sport Science, University of Dayton, 300 College Park Center, Dayton, OH 45469, USA. Electronic address: tipnisr1@udayton.edu.
authors.forename: Rima A
authors.initials: RA
authors.lastname: Tipnis
authors.affiliation: Department of Physical Therapy, University of Dayton, 300 College Park Center, Dayton, OH 45469, USA. Electronic address: panloague1@udayton.edu.
authors.forename: Philip A
authors.initials: PA
authors.lastname: Anloague
authors.affiliation: Department of Health and Sport Science, University of Dayton, 300 College Park Center, Dayton, OH 45469, USA. Electronic address: llaubach1@udayton.edu.
authors.forename: Lloyd L
authors.initials: LL
authors.lastname: Laubach
authors.affiliation: Department of Physical Therapy, University of Dayton, 300 College Park Center, Dayton, OH 45469, USA. Electronic address: jbarrios1@udayton.edu.
authors.forename: Joaquin A
authors.initials: JA
authors.lastname: Barrios
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D061826:Foot Orthoses; D005684:Gait / Q000502:physiology; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000534:rehabilitation; D017060:Patient Satisfaction; D016059:Range of Motion, Articular / Q000502:physiology; D016138:Walking / Q000502:physiology*; D055815:Young Adult
keywords: Arch height; Arch rigidity; Comfort; Knee adduction moment; Lateral wedge