title: Downhill walking gait pattern discriminates between types of knee arthroplasty: improved physiological knee functionality in UKA versus TKA.
abstract: OBJECTIVE
  To determine whether downhill walking gait pattern discriminates between different types of knee arthroplasty.
  
  
  METHODS
  Nineteen unicompartmental knee arthroplasty (UKA) and fourteen total knee arthroplasty (TKA) patients who were well matched demographically and with high Oxford knee scores (OKS) for their operation type were evaluated at a minimum 1 year after their operation with downhill gait analysis. Nineteen healthy young subjects were used as controls. Downhill gait analysis was carried out on an instrumented treadmill that was ramped at the rear to produce a declination of 7°. All subjects after a period of habituation were tested for preferred and top downhill walking speed with associated ground reaction and temporospatial measurements.
  
  
  RESULTS
  The UKA group had higher mean OKS (44.8 ± 2.9 vs 41.9 ± 4.7, p = 0.03) as predicted. The UKA group walked downhill 15% faster than the TKA group (1.75 ± 0.14 vs 1.52 ± 0.13 m/s, p < 0.0001) despite having the same cadence (134.9 ± 8.0 vs 133.9 ± 9.6 steps/min). This 15% difference in speed appeared largely due to a 15% increase in stride length (173 ± 14 vs 150 ± 17 cm, p = 0.0007) and normal weight acceptance, both of which were similar to the controls.
  
  
  CONCLUSIONS
  Using an instrumented treadmill to test a commonly performed task, stride length when walking downhill highlights the functional differences between arthroplasty groups. Near normal restoration of physiological gait pattern was found in unicompartmentals as compared to total knee replacements.
  
  
  METHODS
  Retrospective comparative study, Level III.
authors.affiliation: MSK Lab, Department of Surgery and Cancer, Charing Cross Hospital, Imperial College London, Fulham Palace Road, London, W6 8RF, UK, a.wiik@imperial.ac.uk.
authors.forename: Anatole V
authors.initials: AV
authors.lastname: Wiik
authors.forename: Adeel
authors.initials: A
authors.lastname: Aqil
authors.forename: Sara
authors.initials: S
authors.lastname: Tankard
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Amis
authors.forename: Justin P
authors.initials: JP
authors.lastname: Cobb
mesh_terms: D000328:Adult; D000368:Aged; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016138:Walking / Q000502:physiology*