The influence of shape and sliding distance of femoral head movement loci on the wear of acetabular cups in total hip arthroplasty

Bennett, D; Orr, JF; Beverland, DE; Baker, RJ

Abstract

Wear of the polyethylene acetabular component is the most serious threat to the longterm success of total hip replacements (THRs). Greatly reduced wear rates have been reported for unidirectional, compared to multidirectional, articulation in vitro. This study considers the multidirectional motions experienced at the hip joint as described by movement loci of points on the femoral
head for individual THR patients. A three-dimensional computer program determined the movement
loci of selected points on the femoral head for THR patients and normal subjects using kinematic
data obtained from gait analysis. The sizes and shapes of these loci were quantified by their sliding
distances and aspect ratios with substantial differences exhibited between individual THR patients.
The average sliding distances ranged from 10.0 to 18.1 mm and the average aspect ratios of the loci
ranged from 2.5 to 9.2 for the THR patients. Positive correlations were found between wear rate and
average sliding distance, the inverse of the average aspect ratio of the loci and the product of the
average sliding distance and the inverse of the average aspect ratio of the loci. Patients with a normal
hip joint range of motion produce multidirectional motion loci and tend to experience more wear than patients with more unidirectional motion loci. Differing patterns of multidirectional motion at the hip joint for individual THR patients may explain widely differing wear rates in vivo.

Citation

Bennett, D., Orr, J., Beverland, D., & Baker, R. (2002). The influence of shape and sliding distance of femoral head movement loci on the wear of acetabular cups in total hip arthroplasty. Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, 216(6), 393-402. https://doi.org/10.1243/095441102321032184

• Journal Article Type: Article
• Publication Date: Jan 1, 2002
• Deposit Date: Jul 7, 2011
• Journal: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
• Print ISSN: 0954-4119
• Publisher: SAGE Publications
• Peer Reviewed: Peer Reviewed
• Volume: 216
• Issue: 6
• Pages: 393-402
• DOI: https://doi.org/10.1243/095441102321032184
• Publisher URL: http://dx.doi.org/10.1243/095441102321032184