Stress shielding and stress concentration of contemporary epiphyseal hip prostheses

L. Cristofolini, M. Juszczyk, F. Taddei, R. E. Field, N. Rushton, M. Viceconti

Research output: Contribution to journalArticle

Abstract

After the first early failures, proximal femoral epiphyseal replacement is becoming popular again. Prosthesis-to-bone load transfer is critical for two reasons: stress shielding is suspected of being responsible for a number of failures of early epiphyseal prostheses; stress concentration is probably responsible of the relevant number of early femoral neck fractures in resurfaced patients. The scope of this work was to experimentally investigate the load transfer of a commercial epiphyseal prosthesis (Birmingham Hip Replacement (BHR)) and an innovative prototype proximal epiphyseal replacement. To investigate bone surface strain, ten cadaveric femurs were instrumented with 15 triaxial strain gauges. In addition the cement layer of the prototype was instrumented with embedded gauges to estimate the strain in the adjacent trabecular bone. Six different loading configurations were investigated, with and without muscles. For the BHR prosthesis, significant stress shielding was observed on the posterior side of the head-neck region (the strain was halved); a pronounced stress concentration was observed on the anterior surface (up to five times in some specimens); BHR was quite sensitive to the different loading configurations. For the prototype, the largest stress shielding was observed in the neck region (lower than the BHR; alteration less than 20 per cent); some stress concentration was observed at the head region, close to the rim of the prosthesis (alteration less than 20 per cent); the different loading configurations had similar effects. Such large alterations with respect to the pre-operative conditions were found only in regions where the strain level was low. Conversely, alterations were moderate where the strain was higher. Thus, prosthesis-to-bone load transfer of both devices has been elucidated; the prototype preserved a stress distribution closer to the physiological condition.

Original languageEnglish
Pages (from-to)27-44
Number of pages18
JournalProceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine
Volume223
Issue number1
DOIs
Publication statusPublished - Jan 1 2009

Fingerprint

Hip prostheses
Hip Prosthesis
Shielding
Prostheses and Implants
Stress concentration
Bone
Bone and Bones
Hip
Neck
Head
Loads (forces)
Femoral Neck Fractures
Thigh
Femur
Strain gages
Prosthetics
Gages
Muscle
Cements
Equipment and Supplies

Keywords

  • Embedded strain gauges
  • Epiphyseal hip prostheses
  • Femoral head resurfacing
  • In-vitro bone testing
  • Load transfer
  • Physiologicalloading
  • Proximal femur
  • Stress concentration
  • Stress shielding

ASJC Scopus subject areas

  • Mechanical Engineering
  • Medicine(all)

Cite this

Stress shielding and stress concentration of contemporary epiphyseal hip prostheses. / Cristofolini, L.; Juszczyk, M.; Taddei, F.; Field, R. E.; Rushton, N.; Viceconti, M.

In: Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine, Vol. 223, No. 1, 01.01.2009, p. 27-44.

Research output: Contribution to journalArticle

@article{b09500c02a2a4c7389c9d44d7ed8c402,
title = "Stress shielding and stress concentration of contemporary epiphyseal hip prostheses",
abstract = "After the first early failures, proximal femoral epiphyseal replacement is becoming popular again. Prosthesis-to-bone load transfer is critical for two reasons: stress shielding is suspected of being responsible for a number of failures of early epiphyseal prostheses; stress concentration is probably responsible of the relevant number of early femoral neck fractures in resurfaced patients. The scope of this work was to experimentally investigate the load transfer of a commercial epiphyseal prosthesis (Birmingham Hip Replacement (BHR)) and an innovative prototype proximal epiphyseal replacement. To investigate bone surface strain, ten cadaveric femurs were instrumented with 15 triaxial strain gauges. In addition the cement layer of the prototype was instrumented with embedded gauges to estimate the strain in the adjacent trabecular bone. Six different loading configurations were investigated, with and without muscles. For the BHR prosthesis, significant stress shielding was observed on the posterior side of the head-neck region (the strain was halved); a pronounced stress concentration was observed on the anterior surface (up to five times in some specimens); BHR was quite sensitive to the different loading configurations. For the prototype, the largest stress shielding was observed in the neck region (lower than the BHR; alteration less than 20 per cent); some stress concentration was observed at the head region, close to the rim of the prosthesis (alteration less than 20 per cent); the different loading configurations had similar effects. Such large alterations with respect to the pre-operative conditions were found only in regions where the strain level was low. Conversely, alterations were moderate where the strain was higher. Thus, prosthesis-to-bone load transfer of both devices has been elucidated; the prototype preserved a stress distribution closer to the physiological condition.",
keywords = "Embedded strain gauges, Epiphyseal hip prostheses, Femoral head resurfacing, In-vitro bone testing, Load transfer, Physiologicalloading, Proximal femur, Stress concentration, Stress shielding",
author = "L. Cristofolini and M. Juszczyk and F. Taddei and Field, {R. E.} and N. Rushton and M. Viceconti",
year = "2009",
month = "1",
day = "1",
doi = "10.1243/09544119JEIM470",
language = "English",
volume = "223",
pages = "27--44",
journal = "Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine",
issn = "0954-4119",
publisher = "SAGE Publications Ltd",
number = "1",

}

TY - JOUR

T1 - Stress shielding and stress concentration of contemporary epiphyseal hip prostheses

AU - Cristofolini, L.

AU - Juszczyk, M.

AU - Taddei, F.

AU - Field, R. E.

AU - Rushton, N.

AU - Viceconti, M.

PY - 2009/1/1

Y1 - 2009/1/1

N2 - After the first early failures, proximal femoral epiphyseal replacement is becoming popular again. Prosthesis-to-bone load transfer is critical for two reasons: stress shielding is suspected of being responsible for a number of failures of early epiphyseal prostheses; stress concentration is probably responsible of the relevant number of early femoral neck fractures in resurfaced patients. The scope of this work was to experimentally investigate the load transfer of a commercial epiphyseal prosthesis (Birmingham Hip Replacement (BHR)) and an innovative prototype proximal epiphyseal replacement. To investigate bone surface strain, ten cadaveric femurs were instrumented with 15 triaxial strain gauges. In addition the cement layer of the prototype was instrumented with embedded gauges to estimate the strain in the adjacent trabecular bone. Six different loading configurations were investigated, with and without muscles. For the BHR prosthesis, significant stress shielding was observed on the posterior side of the head-neck region (the strain was halved); a pronounced stress concentration was observed on the anterior surface (up to five times in some specimens); BHR was quite sensitive to the different loading configurations. For the prototype, the largest stress shielding was observed in the neck region (lower than the BHR; alteration less than 20 per cent); some stress concentration was observed at the head region, close to the rim of the prosthesis (alteration less than 20 per cent); the different loading configurations had similar effects. Such large alterations with respect to the pre-operative conditions were found only in regions where the strain level was low. Conversely, alterations were moderate where the strain was higher. Thus, prosthesis-to-bone load transfer of both devices has been elucidated; the prototype preserved a stress distribution closer to the physiological condition.

AB - After the first early failures, proximal femoral epiphyseal replacement is becoming popular again. Prosthesis-to-bone load transfer is critical for two reasons: stress shielding is suspected of being responsible for a number of failures of early epiphyseal prostheses; stress concentration is probably responsible of the relevant number of early femoral neck fractures in resurfaced patients. The scope of this work was to experimentally investigate the load transfer of a commercial epiphyseal prosthesis (Birmingham Hip Replacement (BHR)) and an innovative prototype proximal epiphyseal replacement. To investigate bone surface strain, ten cadaveric femurs were instrumented with 15 triaxial strain gauges. In addition the cement layer of the prototype was instrumented with embedded gauges to estimate the strain in the adjacent trabecular bone. Six different loading configurations were investigated, with and without muscles. For the BHR prosthesis, significant stress shielding was observed on the posterior side of the head-neck region (the strain was halved); a pronounced stress concentration was observed on the anterior surface (up to five times in some specimens); BHR was quite sensitive to the different loading configurations. For the prototype, the largest stress shielding was observed in the neck region (lower than the BHR; alteration less than 20 per cent); some stress concentration was observed at the head region, close to the rim of the prosthesis (alteration less than 20 per cent); the different loading configurations had similar effects. Such large alterations with respect to the pre-operative conditions were found only in regions where the strain level was low. Conversely, alterations were moderate where the strain was higher. Thus, prosthesis-to-bone load transfer of both devices has been elucidated; the prototype preserved a stress distribution closer to the physiological condition.

KW - Embedded strain gauges

KW - Epiphyseal hip prostheses

KW - Femoral head resurfacing

KW - In-vitro bone testing

KW - Load transfer

KW - Physiologicalloading

KW - Proximal femur

KW - Stress concentration

KW - Stress shielding

UR - http://www.scopus.com/inward/record.url?scp=63849152664&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=63849152664&partnerID=8YFLogxK

U2 - 10.1243/09544119JEIM470

DO - 10.1243/09544119JEIM470

M3 - Article

C2 - 19239065

AN - SCOPUS:63849152664

VL - 223

SP - 27

EP - 44

JO - Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

JF - Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

SN - 0954-4119

IS - 1

ER -