title: Does increasing step width alter knee biomechanics in medial compartment knee osteoarthritis patients during stair descent?
abstract: BACKGROUND
  Research shows that one of the first complaints from knee osteoarthritis (OA) patients is difficulty in stair ambulation due to knee pain. Increased step width (SW) has been shown to reduce first and second peak internal knee abduction moments, a surrogate variable for medial compartment knee joint loading, during stair descent in healthy older adults. This study investigates the effects of increased step width (SW) on knee biomechanics and knee pain in medial compartment knee OA patients during stair descent.
  
  
  METHODS
  Thirteen medial compartment knee OA patients were recruited for the study. A motion analysis system was used to obtain three-dimensional joint kinematics. An instrumented staircase was used to collect ground reaction forces (GRF). Participants performed stair descent trials at their self-selected speed using preferred, wide, and wider SW. Participants rated their knee pain levels after each SW condition.
  
  
  RESULTS
  Increased SW had no effect on peak knee abduction moments and knee pain. Patients reported low levels of knee pain during all stair descent trials. The 2nd peak knee adduction angle and frontal plane GRF at time of 2nd peak abduction moment were reduced with increasing SW.
  
  
  CONCLUSIONS
  The findings suggest that increases in SW may not influence knee loads in medial compartment knee OA patients afflicted with low levels of knee pain during stair descent.
authors.affiliation: Health & Sport Science, University of Memphis, Memphis, TN, USA. Electronic address: mrpqette@memphis.edu.
authors.forename: Max R
authors.initials: MR
authors.lastname: Paquette
authors.affiliation: Kinesiology, Recreation and Sport Studies, University of Tennessee, Knoxville, TN, USA.
authors.forename: Songning
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Department of Physical Therapy and Rehabilitation Sciences, Drexel University, Philadelphia, PA, USA.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Milner
authors.affiliation: Rheumatology Division, University of Tennessee Medical Center, Knoxville, TN, USA.
authors.forename: Gary
authors.initials: G
authors.lastname: Klipple
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena / Q000502:physiology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008124:Locomotion / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D064232:Visual Analog Scale
keywords: Abduction moment; Adduction angle; Knee load; Osteoarthritis; Stair walking