title: Lower extremity joint kinematics during stair climbing in knee osteoarthritis.
abstract: OBJECTIVE
  Knee osteoarthritis (OA) is one of the most prevalent chronic lower extremity diseases, causing profound limitation of movement and ability to perform activities of daily living. The purpose of this study was to compare various hip, knee, and ankle joint kinematic variables between knee OA subjects and matched healthy controls during stair ascent and descent.
  
  
  METHODS
  Eighteen subjects with knee OA (age = 60.2 ± 9.9 yr, mass = 90.3 ± 16.7 kg, height = 168.4 ± 9.9 cm) and 18 healthy matched controls (age = 60.3 ± 10.7 yr, mass = 81.1 ± 21.2 kg, height = 168.3 ± 11.9 cm) participated in the study. Subjects performed five ascending and descending trials on a custom-built staircase while their motion was captured three-dimensionally using an eight-camera optical video motion capture system.
  
  
  RESULTS
  Significant group × direction interactions were found for average hip flexion angle at foot strike (P = 0.04), for average ankle adduction angle at foot strike (P = 0.01), and for peak ankle dorsiflexion angle during support (P = 0.05) and swing (P = 0.01). Specifically, knee OA and control subjects demonstrated greater hip flexion angle at foot strike and ankle dorsiflexion angle during swing but showed smaller ankle dorsiflexion angle during support during stair ascent compared with descent. Furthermore, compared with controls, knee OA patients demonstrated greater hip abduction at foot strike (-3.1° ± 3.9°) and smaller peak knee flexion during support (60.4° ± 5.0°) and swing (86.7° ± 5.4°). Time of peak hip abduction (34.2% ± 7.1%), hip flexion (7.0% ± 12.3%), knee flexion (69.8% ± 4.6%), dorsiflexion (51.4% ± 2.9%), and ankle adduction (37.3% ± 20.8%) during support occurred later in the gait cycle for knee OA patients.
  
  
  CONCLUSIONS
  These data demonstrate that knee OA directly influences specific knee joint kinematics and induces kinematic alterations at the hip and ankle perhaps to compensate for the existing knee joint pathology.
authors.affiliation: Department of Exercise and Sport Science and Center on Aging, University of Utah, Salt Lake City, UT 84112, USA. charlie.hickslittle@hsc.utah.edu
authors.forename: Charlie A
authors.initials: CA
authors.lastname: Hicks-Little
authors.forename: Richard D
authors.initials: RD
authors.lastname: Peindl
authors.forename: Tricia J
authors.initials: TJ
authors.lastname: Hubbard
authors.forename: Brian P
authors.initials: BP
authors.lastname: Scannell
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Springer
authors.forename: Susan M
authors.initials: SM
authors.lastname: Odum
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Fehring
authors.forename: Mitchell L
authors.initials: ML
authors.lastname: Cordova
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000843:Ankle Joint / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology