Sensitivity analysis of a cemented hip stem to implant position and cement mantle thickness

Research output: Contribution to journalArticle

Abstract

Patient-specific finite element models of the implanted proximal femur can be built from pre-operative computed tomography scans and post-operative X-rays. However, estimating three-dimensional positioning from two-dimensional radiographs introduces uncertainty in the implant position. Further, accurately measuring the thin cement mantle and the degree of cement-bone interdigitation from imaging data is challenging. To quantify the effect of these uncertainties in stem position and cement thickness, a sensitivity study was performed. A design-of-experiment study was implemented, simulating both gait and stair ascent. Cement mantle stresses and bone-implant interface strains were monitored. The results show that small variations in alignment affect the implant biomechanics, especially around the most proximal and most distal ends of the stem. The results suggest that implant position is more influential than cement thickness. Rotation around the medial-lateral axis is the dominant factor in the proximal zones and stem translations are the dominant factors around the distal tip.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Orthopedics

Keywords

  • total hip replacement, sensitivity, finite element analysis, design-of-experiment, implant alignment
Original languageEnglish
Pages (from-to)1671-1684
JournalComputer Methods in Biomechanics and Biomedical Engineering
Volume17
Issue number15
Publication statusPublished - 2014
Publication categoryResearch
Peer-reviewedYes