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Bone Joint Res. 2013 May 01;2(5):79-83. doi: 10.1302/2046-3758.25.2000150. Print 2013.

Does bone compaction around the helical blade of a proximal femoral nail anti-rotation (PFNA) decrease the risk of cut-out?: A subject-specific computational study.

Bone & joint research

J M Goffin, P Pankaj, A H R W Simpson, R Seil, T G Gerich

Affiliations

  1. The University of Edinburgh, Department of Orthopaedics and Trauma, Little France, Old Dalkeith Road, Edinburgh EH16 4SU, UK.

PMID: 23673407 PMCID: PMC3670539 DOI: 10.1302/2046-3758.25.2000150

Abstract

OBJECTIVES: Because of the contradictory body of evidence related to the potential benefits of helical blades in trochanteric fracture fixation, we studied the effect of bone compaction resulting from the insertion of a proximal femoral nail anti-rotation (PFNA).

METHODS: We developed a subject-specific computational model of a trochanteric fracture (31-A2 in the AO classification) with lack of medial support and varied the bone density to account for variability in bone properties among hip fracture patients.

RESULTS: We show that for a bone density corresponding to 100% of the bone density of the cadaveric femur, there does not seem to be any advantage in using a PFNA with respect to the risk of blade cut-out. On the other hand, in a more osteoporotic femoral head characterised by a density corresponding to 75% of the initial bone density, local bone compaction around the helical blade provides additional bone purchase, thereby decreasing the risk of cut-out, as quantified by the volume of bone susceptible to yielding.

CONCLUSIONS: Our findings indicate benefits of using a PFNA over an intramedullary nail with a conventional lag screw and suggest that any clinical trial reporting surgical outcomes regarding the use of helical blades should include a measure of the femoral head bone density as a covariable.

Keywords: Cadaveric bone; Cut-out; Finite element analysis; Osteosynthesis; PFNA; Trochanteric fracture

References

  1. J Orthop Res. 2011 May;29(5):760-6 - PubMed
  2. Clin Biomech (Bristol, Avon). 2010 Dec;25(10):1053-7 - PubMed
  3. J Biomech. 2008;41(2):356-67 - PubMed
  4. Injury. 2012 Jul;43(7):1227-8 - PubMed
  5. Injury. 2009 Apr;40(4):428-32 - PubMed
  6. J Biomech. 1998 Jul;31(7):601-8 - PubMed
  7. J Biomech. 2007;40(13):2982-9 - PubMed
  8. Injury. 2010 Dec;41(12):1234-8 - PubMed
  9. J Bone Miner Res. 2011 Apr;26(4):881-93 - PubMed
  10. J Orthop Trauma. 1996;10 Suppl 1:v-ix, 1-154 - PubMed
  11. Proc Inst Mech Eng H. 2010 Oct;224(10):1141-52 - PubMed
  12. Injury. 2008 Aug;39(8):932-9 - PubMed
  13. Int Orthop. 2011 Dec;35(12):1855-61 - PubMed
  14. J Biomech. 2008 Aug 7;41(11):2483-91 - PubMed
  15. J Biomech. 2001 Jul;34(7):873-81 - PubMed
  16. Injury. 2010 Jun;41(6):647-51 - PubMed
  17. Instr Course Lect. 2004;53:441-54 - PubMed
  18. J Biomech. 2009 Sep 18;42(13):2165-70 - PubMed
  19. J Bone Joint Surg Br. 2011 May;93(5):616-21 - PubMed
  20. J Biomech. 2001 Jul;34(7):859-71 - PubMed
  21. Clin Biomech (Bristol, Avon). 2009 Jan;24(1):53-8 - PubMed

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