title: Walking on a compliant surface does not enhance kinematic gait asymmetries after unilateral total knee arthroplasty.
abstract: OBJECTIVE
  To investigate gait asymmetries and the effect of walking on compliant surfaces in individuals with unilateral total knee arthroplasty (TKA), hypothesizing that asymmetries would increase as an effect of the compliant surface.
  
  
  METHODS
  Individuals with unilateral TKA ~19 months post-operative (n = 23, median age 59 years) recruited from one orthopaedic clinic and age- and gender-matched healthy individuals without knee complaints (n = 23, median age 56 years) walked at comfortable speed on a hard surface and on a compliant surface. 3D kinematic analyses were made for knee and hip angles in sagittal and frontal planes, stance time, step length, and gait velocity.
  
  
  RESULTS
  Shorter stance time (p < 0.01) and less peak knee flexion (p < 0.001) at weight bearing acceptance was found in the prosthetic side compared with the contralateral side. Larger knee (p < 0.01) and hip (p < 0.001) adduction was found compared with healthy controls. Neither asymmetries between the prosthetic and the contralateral side nor differences compared with healthy controls were enhanced when walking on compliant surfaces compared with hard surfaces.
  
  
  CONCLUSIONS
  The TKA group adapted their gait to compliant surfaces similarly to healthy controls. Gait asymmetries in the TKA group observed on hard surface were not enhanced, and adduction in hip and knee joints did not increase further as an effect of walking on compliant surfaces. Thus, unfavourable knee joint loading did not increase when walking on a compliant surface. This implies that recommendations for walking on soft surfaces to reduce knee joint loading are not counteracted by increased gait asymmetries and unfavourable joint loading configurations.
  
  
  METHODS
  III.
authors.affiliation: Department of Community Medicine and Rehabilitation Physiotherapy, Umeå University, 901 87, Umeå, Sweden.|Department of Physiotherapy, Faculty of Health and Social Sciences, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway.
authors.forename: Joakim
authors.initials: J
authors.lastname: Bjerke
authors.affiliation: Department of Radiation Sciences, Biomedical Engineering, Umeå University, 901 85, Umeå, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Öhberg
authors.affiliation: Surgical and Perioperative Sciences, Umeå University, 901 85, Umeå, Sweden.
authors.forename: Kjell G
authors.initials: KG
authors.lastname: Nilsson
authors.affiliation: Department of Community Medicine and Rehabilitation Physiotherapy, Umeå University, 901 87, Umeå, Sweden. ann-katrin.stensdotter@ntnu.no.|Department of Physiotherapy, Faculty of Health and Social Sciences, Norwegian University of Science and Technology, NTNU, 7491, Trondheim, Norway. ann-katrin.stensdotter@ntnu.no.
authors.forename: Ann-Katrin
authors.initials: AK
authors.lastname: Stensdotter
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000601:surgery; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery*; D011184:Postoperative Period; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing
keywords: Hip joint adduction; Knee joint adduction; Knee joint flexion; Locomotion; Prosthesis