title: Factors predicting weight-bearing asymmetry 1month after unilateral total knee arthroplasty: a cross-sectional study.
abstract: Factors predicting weight-bearing asymmetry (WBA) after unilateral total knee arthroplasty (TKA) are not known. However, identifying modifiable and non-modifiable predictors of WBA is needed to optimize rehabilitation, especially since WBA is negatively correlated to poor functional performance. The purpose of this study was to identify factors predictive of WBA during sit-stand transitions for people 1month following unilateral TKA.
  
  
  METHODS
  Fifty-nine people were tested preoperatively and 1month following unilateral TKA for WBA using average vertical ground reaction force under each foot during the Five Times Sit-to-Stand Test. Candidate variables tested in the regression analysis represented physical impairments (strength, muscle activation, pain, and motion), demographics, anthropometrics, and movement compensations.
  
  
  RESULTS
  WBA, measured as the ratio of surgical/non-surgical limb vertical ground reaction force, was 0.69 (0.18) (mean (SD)) 1month after TKA. Regression analysis identified preoperative WBA (β=0.40), quadriceps strength ratio (β=0.31), and hamstrings strength ratio (β=0.19) as factors predictive of WBA 1month after TKA (R(2)=0.30).
  
  
  CONCLUSIONS
  Greater amounts of WBA 1month after TKA are predicted by modifiable factors including habitual movement pattern and asymmetry in quadriceps and hamstrings strength.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Physical Therapy Program, University of Colorado, Aurora, CO 80045, United States. cory.christiansen@ucdenver.edu
authors.forename: Cory L
authors.initials: CL
authors.lastname: Christiansen
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bade
authors.forename: David A
authors.initials: DA
authors.lastname: Weitzenkamp
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Stevens-Lapsley
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000534:rehabilitation*; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology; D020127:Recovery of Function / Q000502:physiology; D012044:Regression Analysis; D012307:Risk Factors; D013848:Thigh; D016474:Weight-Bearing