title: Contact surface motion paths associated with leg length inequality following unilateral total hip replacement.
abstract: In the past, there has been little research into leg length inequality (LLI) and its effect on hip arthroplasty bearing longevity. This investigation aimed to determine the effects of post-operative LLI on hip motions during gait and to postulate the subsequent influence on the wear of the artificial hip joint replacement. Motion data from a clinical gait analysis were processed with an in-house computational model to plot graphs showing the movement of loci of 20 points on the femoral head during one gait cycle for two cohorts: 19 LLI patients and 38 normal healthy patients. Loci paths were quantified by calculating the aspect ratio (AR) of the path shape. It was found that on average, LLI patients had a reduction in flexion/extension and abduction/adduction. Furthermore, the AR of LLI patients was found to be 8% smaller than the normal group. The shorter, more multidirectional, motion paths in LLI patients would suggest the potential for greater wear in a polyethylene bearing compared to an asymptomatic, non-LLI patient. The results have potential implications towards preclinical wear testing of joint replacements.
authors: Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, UK.
authors: Sarah
authors: S
authors: Budenberg
authors: Anthony
authors: A
authors: Redmond
authors: Derek
authors: D
authors: White
authors: Andrew
authors: A
authors: Grainger
authors: Philip
authors: P
authors: O'Connor
authors: Martin H
authors: MH
authors: Stone
authors: Todd D
authors: TD
authors: Stewart
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D003198:Computer Simulation; D005260:Female; D005684:Gait; D006801:Humans; D007593:Joint Instability / Q000150:complications / Q000503:physiopathology* / Q000601:surgery*; D007870:Leg Length Inequality / Q000209:etiology* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D016059:Range of Motion, Articular; D016896:Treatment Outcome; D055815:Young Adult
keywords: Leg length inequality; arthroplasty; gait; hip; wear