Finite element modelling of primary hip stem stability: The effect of interference fit
The most commonly reported complications related to cementless hip stems are loosening and thigh pain; both of these have been attributed to high levels of relative micromotion at the bone–implant interface due to insufficient primary fixation. Primary fixation is believed by many to rely on achie...
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| Format: | Article |
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Elsevier
2008
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| Online Access: | http://eprints.utm.my/5418/ |
| _version_ | 1848891048501182464 |
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| author | Abdul-Kadir, Mohammed Rafiq Ulrich, Hansen Ralf, Klabunde Duncan, Lucas Andrew, Amis |
| author_facet | Abdul-Kadir, Mohammed Rafiq Ulrich, Hansen Ralf, Klabunde Duncan, Lucas Andrew, Amis |
| author_sort | Abdul-Kadir, Mohammed Rafiq |
| building | UTeM Institutional Repository |
| collection | Online Access |
| description | The most commonly reported complications related to cementless hip stems are loosening and thigh pain; both of these have been attributed to high levels of relative micromotion at the bone–implant interface due to insufficient primary fixation. Primary fixation is believed by many to rely on achieving a sufficient interference fit between the implant and the bone. However, attempting to achieve a high interference fit not infrequently leads to femoral canal fracture either intra-operatively or soon after. The appropriate range of diametrical interference fit that ensures primary stability without risking femoral fracture is not well understood. In this study, a finite element model was constructed to predict micromotion and, therefore, instability of femoral stems. The model was correlated with an in vitro micromotion experiment carried out on four cadaver femurs. It was confirmed that interference fit has a very significant effect on micromotion and ignoring this parameter in an analysis of primary stability is likely to underestimate the stability of the stem. Furthermore, it was predicted that the optimal level of interference fit is around 50 μm as this is sufficient to achieve good primary fixation while having a safety factor of 2 against femoral canal fracture. This result is of clinical relevance as it indicates a recommendation for the surgeon to err on the side of a low interference fit rather than risking femoral fracture.
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| first_indexed | 2025-11-15T20:51:46Z |
| format | Article |
| id | utm-5418 |
| institution | Universiti Teknologi Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-15T20:51:46Z |
| publishDate | 2008 |
| publisher | Elsevier |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | utm-54182017-10-09T05:40:45Z http://eprints.utm.my/5418/ Finite element modelling of primary hip stem stability: The effect of interference fit Abdul-Kadir, Mohammed Rafiq Ulrich, Hansen Ralf, Klabunde Duncan, Lucas Andrew, Amis TJ Mechanical engineering and machinery The most commonly reported complications related to cementless hip stems are loosening and thigh pain; both of these have been attributed to high levels of relative micromotion at the bone–implant interface due to insufficient primary fixation. Primary fixation is believed by many to rely on achieving a sufficient interference fit between the implant and the bone. However, attempting to achieve a high interference fit not infrequently leads to femoral canal fracture either intra-operatively or soon after. The appropriate range of diametrical interference fit that ensures primary stability without risking femoral fracture is not well understood. In this study, a finite element model was constructed to predict micromotion and, therefore, instability of femoral stems. The model was correlated with an in vitro micromotion experiment carried out on four cadaver femurs. It was confirmed that interference fit has a very significant effect on micromotion and ignoring this parameter in an analysis of primary stability is likely to underestimate the stability of the stem. Furthermore, it was predicted that the optimal level of interference fit is around 50 μm as this is sufficient to achieve good primary fixation while having a safety factor of 2 against femoral canal fracture. This result is of clinical relevance as it indicates a recommendation for the surgeon to err on the side of a low interference fit rather than risking femoral fracture. Elsevier 2008 Article PeerReviewed Abdul-Kadir, Mohammed Rafiq and Ulrich, Hansen and Ralf, Klabunde and Duncan, Lucas and Andrew, Amis (2008) Finite element modelling of primary hip stem stability: The effect of interference fit. Journal of Biomechanics, 41 (Issue 3). 587-594 . ISSN 0021-9290 http://dx.doi.org/10.1016/j.jbiomech.2007.10.009 doi:10.1016/j.jbiomech.2007.10.009 |
| spellingShingle | TJ Mechanical engineering and machinery Abdul-Kadir, Mohammed Rafiq Ulrich, Hansen Ralf, Klabunde Duncan, Lucas Andrew, Amis Finite element modelling of primary hip stem stability: The effect of interference fit |
| title | Finite element modelling of primary hip stem stability: The effect of interference fit |
| title_full | Finite element modelling of primary hip stem stability: The effect of interference fit |
| title_fullStr | Finite element modelling of primary hip stem stability: The effect of interference fit |
| title_full_unstemmed | Finite element modelling of primary hip stem stability: The effect of interference fit |
| title_short | Finite element modelling of primary hip stem stability: The effect of interference fit |
| title_sort | finite element modelling of primary hip stem stability: the effect of interference fit |
| topic | TJ Mechanical engineering and machinery |
| url | http://eprints.utm.my/5418/ http://eprints.utm.my/5418/ http://eprints.utm.my/5418/ |