Efficient computational method for assessing the effects of implant positioning in cementless total hip replacements

Mamadou Bah, Prasanth Nair, Mark Taylor, Martin Browne

    Research output: Contribution to journalArticlepeer-review

    38 Citations (Scopus)

    Abstract

    The present work describes a statistical investigation into the effects of implant positioning on the initial stability of a cementless total hip replacement (THR). Mesh morphing was combined with design of computer experiments to automatically construct Finite Element (FE) meshes for a range of pre-defined femur-implant configurations and to predict implant micromotions under joint contact and muscle loading. Computed micromotions, in turn, are postprocessed using a Bayesian approach to: (a) compute the main effects of implant orientation angles, (b) predict the sensitivities of the considered implant performance metrics with respect to implant ante-retroversion, varus-valgus and antero-posterior orientation angles and (c) identify implant positions that maximise and minimise each metric. It is found that the percentage of implant area with micromotion greater than 50 γm, average and maximum micromotions are all more sensitive to antero-posterior orientation than ante-retroversion and varus-valgus orientation. Sensitivities, combined with the main effect results, suggest that bone is less likely to grow if the implant is increasingly moved from the neutral position towards the anterior part of the femur, where the highest micromotions occur. The computed implant best position leads to a percentage of implant area with micromotion greater than 50 γm of 1.14 when using this metric compared to 14.6 and 5.95 in the worst and neutrally positioned implant cases. In contrast, when the implant average/maximum micromotion is used to assess the THR performance, the implant best position corresponds to average/maximum micromotion of 9 γm/59 γm, compared to 20 γm/114 γm and 13 γm/71 γm in the worst and neutral positions, respectively. The proposed computational framework can be extended further to study the effects of uncertainty and variability in anatomy, bone mechanical properties, loading or bone-implant interface contact conditions.

    Original languageEnglish
    Pages (from-to)1417-1422
    Number of pages6
    JournalJournal of Biomechanics
    Volume44
    Issue number7
    DOIs
    Publication statusPublished - 29 Apr 2011

    Keywords

    • Bayesian Gaussian process modelling
    • Cementless hip replacement
    • Contact analysis
    • Design of experiments
    • Finite element mesh
    • Implant positioning
    • Morphing

    Fingerprint Dive into the research topics of 'Efficient computational method for assessing the effects of implant positioning in cementless total hip replacements'. Together they form a unique fingerprint.

    Cite this