title: Preoperative factors associated with postoperative gait kinematics and kinetics after total hip arthroplasty.
abstract: OBJECTIVE
  To determine how patient factors: age, sex, body mass index (BMI), clinical scores and physical exam findings, are associated with gait recovery after total hip arthroplasty (THA).
  
  
  METHODS
  145 subjects, who were evaluated with standard gait analysis, the Harris Hip Score (HHS), and a physical exam including passive range of motion (ROM), hip abductor strength assessment, before and after primary unilateral THA, were identified from an IRB-approved repository. Sagittal plane dynamic ROM and 3D peak external moments were averaged from operated-side normal-speed trials at each visit. We used linear regression analysis to evaluate the association among preoperative clinical factors and postoperative gait, with and without controlling for the influence of preoperative gait variables.
  
  
  RESULTS
  Sagittal and transverse plane moments, and the peak abduction moment seen in early stance, significantly improved after THA (p < 0.001, effect size d = 0.22-1.04). The peak adduction moment did not change significantly (p = 0.646), although the change ranged from -2.7 to + 4.0 %Body weight × height (-80% to +315%). Preoperative gait, clinical factors and patient characteristics predicted up to 33% of the variability in postoperative gait. Notably, greater preoperative abductor strength was associated with higher postoperative adduction and external rotation moments (R = 0.197-0.266, p < 0.05) after adjusting for age, sex, BMI and preoperative gait.
  
  
  CONCLUSIONS
  Preoperative clinical factors predicted several specific aspects of objectively-characterized postoperative gait function. Physical exam findings can augment the predictive ability of clinical outcome measures, and potentially help guide rehabilitation plans.
authors.affiliation: Department of Kinesiology and Nutrition, Department of Bioengineering, University of Illinois at Chicago, USA. Electronic address: kfouch1@uic.edu.
authors.forename: Kharma C
authors.initials: KC
authors.lastname: Foucher
authors.affiliation: Department of Epidemiology and Biostatistics, University of Illinois at Chicago, USA. Electronic address: sallyf@uic.edu.
authors.forename: Sally
authors.initials: S
authors.lastname: Freels
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D001696:Biomechanical Phenomena; D016208:Databases, Factual; D005260:Female; D005271:Femur Head Necrosis / Q000503:physiopathology / Q000601:surgery*; D005684:Gait; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000503:physiopathology / Q000601:surgery*; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012720:Severity of Illness Index; D012737:Sex Factors; D016896:Treatment Outcome
keywords: Biomechanics; Functional recovery; Gait; Outcome measures; Total hip arthroplasty