title: Postural stability in relation to anthropometric and functional characteristics in women with knee osteoarthritis following total knee arthroplasty.
abstract: BACKGROUND
  Due to the controversial information about postural stability in patients with lower limb joints osteoarthritis (OA), the following main questions are raised: how serious is the postural stability disturbance and which factors have an impact on postural stability before and after total knee arthroplasty (TKA).
  
  
  METHODS
  Force plate was used to assess postural stability and custom-made dynamometer was used to assess isometric maximal voluntary contraction (MVC) force of leg extensor muscles; besides, knee pain and knee range of motion (ROM) was evaluated in 14 female patients (aged 46-68 years) with knee OA 1 day before, and 3 and 6 months following TKA and once in healthy controls (aged 48-70). Relationship between postural stability during standing and selected anthropometric and functional characteristics were investigated with Spearman's correlation coefficients.
  
  
  RESULTS
  Remarkable reduction of knee pain and improvement in active ROM for the operated leg were shown after unilateral TKA. MVC force of leg extensor muscles achieved the preoperative level half a year after TKA. The centre of pressure (COP) of sway displacement in anterioposterior (AP) and mediolateral direction and the equivalent area of COP sway for the operated leg did not differ before, 3 and 6 months after TKA and compared to the non-operated leg. The trace speed was 6 months after TKA equal to the preoperative level. Only the COP of sway displacement in AP direction is significantly greater in knee OA patients both before and after TKA compared with healthy controls.
  
  
  CONCLUSIONS
  Knee OA patients' postural stability characteristics did not differ significantly both before and after TKA. Compared to healthy controls, the COP of sway displacement in AP direction is mostly disturbed. Correlation analysis confirms that increased postural sway is associated with an increased equivalent area of COP. In knee OA patients higher body mass index ensures reduced trace speed and lower knee ROM.
  
  
  METHODS
  Prospective comparative study, Level II.
authors: Institute of Exercise Biology and Physiotherapy, University of Tartu, 5 Jakobi Street, 51014, Tartu, Estonia, Doris.Vahtrik@ut.ee.
authors: Doris
authors: D
authors: Vahtrik
authors: Jaan
authors: J
authors: Ereline
authors: Helena
authors: H
authors: Gapeyeva
authors: Mati
authors: M
authors: Pääsuke
mesh_terms: D000368:Aged; D000886:Anthropometry; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D007866:Leg / Q000601:surgery; D035002:Lower Extremity / Q000601:surgery; D008875:Middle Aged; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000601:surgery; D010146:Pain / Q000601:surgery; D011184:Postoperative Period; D004856:Postural Balance / Q000502:physiology*; D057234:Preoperative Period; D011312:Pressure; D011446:Prospective Studies; D016059:Range of Motion, Articular / Q000502:physiology