title: Frontal plane kinematics in walking with moderate hip osteoarthritis: Stability and fall risk.
abstract: BACKGROUND
  Hip abductor weakness and unilateral pain in patients with moderate hip osteoarthritis may induce changes in frontal plane kinematics during walking that could affect stability and fall risk.
  
  
  METHODS
  In 12 fall-prone patients with moderate hip osteoarthritis, 12 healthy peers, and 12 young controls, we assessed the number of falls in the preceding year, hip abductor strength, fear of falling, Harris Hip Score, and pain. Subjects walked on a treadmill with increasing speeds, and kinematics were measured opto-electronically. Parameters reflecting gait stability and regressions of frontal plane center of mass movements on foot placement were calculated. We analyzed the effects of, and interactions with group, and regression of all variables on number of falls.
  
  
  RESULTS
  Patients walked with quicker and wider steps, stood shorter on their affected leg, and had larger peak speeds of frontal plane movements of the center of mass, especially toward their unaffected side. Patients' static margins of stability were larger, but the unaffected dynamic margin of stability was similar between groups. Frontal plane position and acceleration of the center of mass predicted subsequent step width. The peak speed of frontal plane movements toward unaffected had 55% common variance with number of falls, and adding the Harris Hip Score into bivariate regression led to 83% "explained" variance.
  
  
  CONCLUSIONS
  Quickening and widening steps probably increase stability. Shorter affected side stance time to avoid pain, and/or weakened affected side hip abductors, may lead to faster frontal plane trunk movements toward the unaffected side, which could contribute to fall risk.
authors.affiliation: First Clinical College of Fujian Medical University, Fuzhou, Fujian, PR China; Department of Orthopaedics, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China; Department of Orthopaedics, First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, PR China; Orthopaedic Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, PR China.
authors.forename: XiaoBin
authors.initials: X
authors.lastname: Lin
authors.affiliation: Orthopaedic Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, PR China; MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands. Electronic address: ogmeijer@yahoo.com.
authors.forename: Onno G
authors.initials: OG
authors.lastname: Meijer
authors.affiliation: First Clinical College of Fujian Medical University, Fuzhou, Fujian, PR China; Department of Orthopaedics, First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, PR China. Electronic address: jianhual@126.com.
authors.forename: JianHua
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Orthopaedics, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China; Orthopaedic Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, PR China.
authors.forename: WenHua
authors.initials: W
authors.lastname: Wu
authors.affiliation: Department of Orthopaedics, Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China; Orthopaedic Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, PR China.
authors.forename: XiaoCong
authors.initials: X
authors.lastname: Lin
authors.affiliation: Orthopaedic Biomechanics Laboratory, Fujian Medical University, Quanzhou, Fujian, PR China; Department of Orthopaedics, The 175th Hospital of PLA, Affiliated Dongnan Hospital of Xiamen University, Zhangzhou, Fujian, PR China.
authors.forename: BoWei
authors.initials: B
authors.lastname: Liang
authors.affiliation: MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
authors.forename: Jaap H
authors.initials: JH
authors.lastname: van Dieën
authors.affiliation: Department of Orthopaedics, First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, PR China; MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University, Amsterdam, The Netherlands.
authors.forename: Sjoerd M
authors.initials: SM
authors.lastname: Bruijn
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005080:Exercise Test; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D015207:Osteoarthritis, Hip / Q000503:physiopathology*; D012044:Regression Analysis; D060726:Torso; D016138:Walking; D055815:Young Adult
keywords: Fall risk; Frontal plane balance; Gait analysis; Hip osteoarthritis; Trunk movements