title: Changes in sagittal ground reaction forces after intra-articular hyaluronate injections for knee osteoarthritis.
abstract: OBJECTIVE
  To examine the gait patterns and the sagittal ground reaction forces (GRFs) in persons with knee osteoarthritis (OA) after intra-articular injection of hyaluronate and to investigate the duration of its treatment effectiveness.
  
  
  METHODS
  Case-comparison study.
  
  
  METHODS
  Gait laboratory in a tertiary care center.
  
  
  METHODS
  Fifteen subjects (30 knees) with symptomatic knee OA (stage I or II, according to the Ahlbäck grading system), and 15 age-, mass-, and gender-matched non-OA control subjects (30 knees).
  
  
  METHODS
  After initial gait analysis, the group with knee OA received 5 weekly intra-articular injections of hyaluronate to bilateral knees. Gait analysis was performed again for the group with knee OA after the completion of hyaluronate injections.
  
  
  METHODS
  Forceplate sagittal GRFs and gait parameters of velocity, cadence, step length, and stride time.
  
  
  RESULTS
  The distinctive 2-peak force vector GRF was lost in persons with knee OA. The first peak rise time was significantly delayed (P<.05). The group with knee OA also revealed slower walking velocity and cadence, as well as longer stride time, than the control group (P<.05). The distinctive 2-peak force vector GRF diagram could be recovered in patients with knee OA after the completion of hyaluronate injections.
  
  
  CONCLUSIONS
  Gait patterns and GRFs improved significantly after intra-articular knee injection of hyaluronate in persons with Ahlbäck stages I and II knee OA. The clinical treatment effect was immediate and may last for 6 months or more.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, 5 Fu-Hsin Street, Kwei-Shan, Tao-Yuan 333, Taiwan. fttang@adm.cgmh.org.tw
authors.forename: Simon F
authors.initials: SF
authors.lastname: Tang
authors.forename: Carl P
authors.initials: CP
authors.lastname: Chen
authors.forename: Max J
authors.initials: MJ
authors.lastname: Chen
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Pei
authors.forename: Yiu-Chung
authors.initials: YC
authors.lastname: Lau
authors.forename: Chau-Peng
authors.initials: CP
authors.lastname: Leong
mesh_terms: D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D006820:Hyaluronic Acid / Q000627:therapeutic use*; D007270:Injections, Intra-Articular; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000188:drug therapy* / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D000276:Adjuvants, Immunologic; D006820:Hyaluronic Acid