Can larger cemented femoral components reduce periprosthetic fractures?

Ginsel, Bastiaan, Crawford, Ross W., Wilson, Lance J., Morishima, Takkan, & Whitehouse, Sarah L. (2013) Can larger cemented femoral components reduce periprosthetic fractures? In International Society for Technology in Arthroplasty (ISTA 0213), 16-19 October 2013, Florida, USA.

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Abstract

Introduction

The risk for late periprosthetic fractures is higher in patients treated for a neck of femur fracture compared to those treated for osteoarthritis. It has been hypothesised that osteopenia and consequent decreased stiffness of the proximal femur are responsible for this. We investigated if a femoral component with a bigger body would increase the torque to failure in a biaxially loaded composite sawbone model.

Method

A biomechanical composite sawbone model was used. Two different body sizes (Exeter 44-1 vs 44-4) of a polished tapered cemented stem were implanted by an experienced surgeon, in 7 sawbones each and loaded at 40 deg/s internal rotation until failure. Torque to fracture and fracture energy were measured using a biaxial materials testing device (Instron 8874). Data are non-parametric and tested with Mann-Whitney U-test.

Results

The mean torque load to fracture was 154.1 NM (SD 4.4) for the 44-1 stem and 229 NM (SD10.9) for the 44-4 stem (p = 0.01). The mean fracture energy was 9.6 J (SD1.2) for the 44-1 stem and 17.2 J (SD2.0) for the 44-4 stem (p = 0.14).

Conclusion

the use of a large body polished tapered cemented stem for neck of femur fractures increases the torque to failure in a biomechanical model and therefore is likely to reduce late periprosthetic fracture risk in this vulnerable cohort.

Impact and interest:

2 citations in Web of Science®
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ID Code: 75535
Item Type: Conference Item (Presentation)
Refereed: Yes
Keywords: bigger body stem, periprosthetic fracture, fracture load, stress shielding, biomechanical study, sawbone study
ISSN: 2049-4408
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > CLINICAL SCIENCES (110300) > Orthopaedics (110314)
Divisions: Current > Schools > School of Chemistry, Physics & Mechanical Engineering
Current > Institutes > Institute of Health and Biomedical Innovation
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Deposited On: 25 Aug 2014 23:20
Last Modified: 25 Aug 2014 23:20

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