title: The gait of patients with one resurfacing and one replacement hip: a single blinded controlled study.
abstract: OBJECTIVE
  Post arthroplasty gait analysis has up till now been performed on subjects walking slowly on flat ground rather than challenging them at faster speeds or walking uphill. We therefore asked: (1) Is there a measurable difference in the performance of hip resurfacing arthroplasty (HRA) and total hip arthroplasty (THA) limbs at patients' self-determined fastest walking speeds and steepest inclines? and (2) Is there a relationship between the observed differences between the gait of HRA and THA implanted limbs and patient walking speeds and inclines.
  
  
  METHODS
  In an ethically approved study we recruited patients with bilateral hip arthroplasties: one HRA and one THA. Nine subjects were assessed using an instrumented treadmill at a range of speeds and inclines by a blinded observer. The ground reaction forces of subjects were recorded and an age, sex and BMI matched control group was used for comparison.
  
  
  RESULTS
  Increasing walking speed correlated strongly with between leg differences in weight acceptance (r = 0.9, p = 0.000) and push-off force (r = 0.79, p = 0.002). HRA implanted limbs accepted significantly more weight at top walking speeds (1208 N ± 320 versus 1279 N ± 370, p = 0.026) and pushed off with greater force when walking uphill (818 N ± 163 versus 855 ± 166, p = 0.012). HRA limbs more closely approximated to the gait of the normal control group.
  
  
  CONCLUSIONS
  Arthroplasty implants do have an impact on the gait characteristics of patients. Differences in gait are more likely to be evident when assessment is made at fast speeds and walking uphill. This study suggests that HRA may enable a more normal gait.
authors: Department of Surgery and Cancer, Charing Cross Hospital, Imperial College London, Fulham Palace Road, London, W6 8RF, UK. a.aqil@imperial.ac.uk
authors: Adeel
authors: A
authors: Aqil
authors: Roshan
authors: R
authors: Drabu
authors: Jeroen H
authors: JH
authors: Bergmann
authors: Milad
authors: M
authors: Masjedi
authors: Victoria
authors: V
authors: Manning
authors: Barry
authors: B
authors: Andrews
authors: Sarah K
authors: SK
authors: Muirhead-Allwood
authors: Justin P
authors: JP
authors: Cobb
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods / Q000534:rehabilitation*; D001696:Biomechanical Phenomena; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology*; D016474:Weight-Bearing