title: External knee adduction and flexion moments during gait and medial tibiofemoral disease progression in knee osteoarthritis.
abstract: OBJECTIVE
  Test the hypothesis that greater baseline peak external knee adduction moment (KAM), KAM impulse, and peak external knee flexion moment (KFM) during the stance phase of gait are associated with baseline-to-2-year medial tibiofemoral cartilage damage and bone marrow lesion progression, and cartilage thickness loss.
  
  
  METHODS
  Participants all had knee OA in at least one knee. Baseline peak KAM, KAM impulse, and peak KFM (normalized to body weight and height) were captured and computed using a motion analysis system and six force plates. Participants underwent MRI of both knees at baseline and 2 years later. To assess the association between baseline moments and baseline-to-2-year semiquantitative cartilage damage and bone marrow lesion progression and quantitative cartilage thickness loss, we used logistic and linear regressions with generalized estimating equations (GEE), adjusting for gait speed, age, gender, disease severity, knee pain severity, and medication use.
  
  
  RESULTS
  The sample consisted of 391 knees (204 persons): mean age 64.2 years (SD 10.0); BMI 28.4 kg/m(2) (5.7); 156 (76.5%) women. Greater baseline peak KAM and KAM impulse were each associated with worsening of medial bone marrow lesions, but not cartilage damage. Higher baseline KAM impulse was associated with 2-year medial cartilage thickness loss assessed both as % loss and as a threshold of loss, whereas peak KAM was related only to % loss. There was no relationship between baseline peak KFM and any medial disease progression outcome measures.
  
  
  CONCLUSIONS
  Findings support targeting KAM parameters in an effort to delay medial OA disease progression.
authors: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: hsini@northwestern.edu.
authors: A H
authors: AH
authors: Chang
authors: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: k-moisio@northwestern.edu.
authors: K C
authors: KC
authors: Moisio
authors: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: jchmiel@northwestern.edu.
authors: J S
authors: JS
authors: Chmiel
authors: Institute of Anatomy, Paracelsus Medical University Salzburg & Nuremberg, Salzburg, Austria. Electronic address: felix.eckstein@pmu.ac.at.
authors: F
authors: F
authors: Eckstein
authors: Department of Radiology, Boston University School of Medicine, Boston, MA, USA. Electronic address: ali.Guermazi@bmc.org.
authors: A
authors: A
authors: Guermazi
authors: Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA. Electronic address: p-prasad2@northwestern.edu.
authors: P V
authors: PV
authors: Prasad
authors: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: y-zhang3@northwestern.edu.
authors: Y
authors: Y
authors: Zhang
authors: Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: o-almagor@northwestern.edu.
authors: O
authors: O
authors: Almagor
authors: Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: laura.belisle@northwestern.edu.
authors: L
authors: L
authors: Belisle
authors: Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: k-hayes@northwestern.edu.
authors: K
authors: K
authors: Hayes
authors: Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. Electronic address: l-sharma@northwestern.edu.
authors: L
authors: L
authors: Sharma
mesh_terms: D000368:Aged; D001853:Bone Marrow / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology / Q000503:physiopathology*; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology*
keywords: Biomechanics; Gait; Knee osteoarthritis