Low cost polymer intramedullary nails for fracture fixation: a biomechanical study in a porcine femur model.
BACKGROUND
Whilst intramedullary nailing is a commonly accepted technique for lower limb fracture fixation, the cost of nails can be prohibitive in hospitals in developing nations. In these institutions bone cement has found many off label applications, that whilst are effective do not meet manufacturers guidelines. The aim of this study was to examine the biomechanics of one such application, fracture fixation using a bone cement intramedullary nail.


METHODS
Five porcine femurs underwent a mid-shaft osteotomy and were fixed using a nail made from antibiotic simplex bone cement. The torsional and flexural stiffness and shear modulus of these constructs were compared to five intact porcine femurs.


RESULTS
The bone cement intramedullary nail was able to achieve relative stability in both torsion, with a mean shear modulus of 0.17 GPa and in flexion with a mean flexural stiffness of 358 N/mm. This corresponds to 47 and 22% of the respective measurements in the intact femurs. The mean ultimate flexural strength of fracture/nail constructs was 936 +/- 350 N, which is 20% of the ultimate flexural strength of an intact porcine femur (4,820 +/- 698 N).


CONCLUSIONS
Intramedullary nails made from bone cement were able to provide sufficient promise in this situation to warrant further investigation for their applicability as a low cost alternative for use in developing countries.
Lewis
D
D
AOSpine Reference Centre, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
Lutton
C
C
Wilson
L J
LJ
Crawford
R W
RW
Goss
B
B
D000818:Animals; D001858:Bone Nails / Q000191:economics*; D017046:Cost Savings; D003906:Developing Countries; D004548:Elasticity; D004868:Equipment Failure / Q000191:economics; D005269:Femur / Q000601:surgery; D005594:Fracture Fixation, Intramedullary / Q000191:economics* / Q000295:instrumentation*; D019904:Polymethyl Methacrylate / Q000191:economics*; D033081:Shear Strength; D013552:Swine; D054159:Torsion, Mechanical
D019904:Polymethyl Methacrylate