title: Improvement of walking speed and gait symmetry in older patients after hip arthroplasty: a prospective cohort study.
abstract: BACKGROUND
  Retraining walking in patients after hip or knee arthroplasty is an important component of rehabilitation especially in older persons whose social interactions are influenced by their level of mobility. The objective of this study was to test the effect of an intensive inpatient rehabilitation program on walking speed and gait symmetry in patients after hip arthroplasty (THA) using inertial sensor technology.
  
  
  METHODS
  Twenty-nine patients undergoing a 4-week inpatient rehabilitation program following THA and 30 age-matched healthy subjects participated in this study. Walking speed and gait symmetry parameters were measured using inertial sensor device for standardized walking trials (2*20.3 m in a gym) at their self-selected normal and fast walking speeds on postoperative days 15, 21, and 27 in patients and in a single session in control subjects. Walking speed was measured using timing lights. Gait symmetry was determined using autocorrelation calculation of the cranio-caudal (CC) acceleration signals from an inertial sensor placed at the lower spine.
  
  
  RESULTS
  Walking speed and gait symmetry improved from postoperative days 15-27 (speed, female: 3.2 and 4.5 m/s; male: 4.2 and 5.2 m/s; autocorrelation, female: 0.77 and 0.81; male: 0.70 and 0.79; P <0.001 for all). After the 4-week rehabilitation program, walking speed and gait symmetry were still lower than those in control subjects (speed, female 4.5 m/s vs. 5.7 m/s; male: 5.2 m/s vs. 5.3 m/s; autocorrelation, female: 0.81 vs. 0.88; male: 0.79 vs. 0.90; P <0.001 for all).
  
  
  CONCLUSIONS
  While patients with THA improved their walking capacity during a 4-week inpatient rehabilitation program, subsequent intensive gait training is warranted for achieving normal gait symmetry. Inertial sensor technology may be a useful tool for evaluating the rehabilitation process during the post-inpatient period.
authors.affiliation: Institute of Sport and Sport Sciences, Albert-Ludwigs Universität Freiburg, Schwarzwaldstr 175, 79117, Freiburg, Germany. walter.rapp@sport.uni-freiburg.de.
authors.forename: Walter
authors.initials: W
authors.lastname: Rapp
authors.affiliation: Conservative & Rehabilitative Orthopedics, Technische Universität München, Munich, Germany. torsten.brauner@tum.de.
authors.forename: Torsten
authors.initials: T
authors.lastname: Brauner
authors.affiliation: Conservative & Rehabilitative Orthopedics, Technische Universität München, Munich, Germany. linda.weber@tum.de.
authors.forename: Linda
authors.initials: L
authors.lastname: Weber
authors.affiliation: Department of Food and Nutrition and Sport Science, University of Gothenburg, Gothenburg, Sweden. stefan.grau@gu.se.
authors.forename: Stefan
authors.initials: S
authors.lastname: Grau
authors.affiliation: Department of Orthopaedics, University Hospital Basel, Basel, Switzerland. annegret.muendermann@unibas.ch.
authors.forename: Annegret
authors.initials: A
authors.lastname: Mündermann
authors.affiliation: Conservative & Rehabilitative Orthopedics, Technische Universität München, Munich, Germany. t.horstmann@medicalpark.de.|Medical Park St. Hubertus, Bad Wiessee, Germany. t.horstmann@medicalpark.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Horstmann
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000534:rehabilitation*; D016022:Case-Control Studies; D005260:Female; D005684:Gait; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016138:Walking / Q000502:physiology*