Article

Flexible intramedullary nail fixation of dislocated diaphyseal femur
fractures has gained wide acceptance for children and adolescents with open
physes. Studies with a special emphasis on complications reveal frequent problems
regarding stability, usually in complex fracture types such as spiral fractures
and in older children weighing >40kg. This biomechanical study analyses how much
the material of the nails influences the stiffness in a synthetic bone model.
METHODS: Twenty-four composite grafts (Sawbones(R), 4th generation, medullar
canal of 10mm) with an identical spiral fracture were used in three
configurations of eight grafts. Elastic stable intramedullary nailing was
performed in a retrograde C-shaped manner with two nails of equal size (2x3.5mm).
Close contact of the fragments could be achieved. We compared Group A (steel
nails) with Group B and C (two types of titanium nails). All specimens underwent
4-point bending, torsion and axial compression in the 0 degrees and 9 degrees
positions, and the results were analysed. FINDINGS: Group A (steel nails)
revealed a significantly higher stiffness in all directions than Group B. Apart
from compression in the 9 degrees position this steel nail fixation showed
significant higher stiffness than titanium nails of Group C. Comparing Group B
and C did not show an systematic difference. INTERPRETATION: In this
biomechanical study with composite artificial bones the use of steel Nails
demonstrated the highest stiffness in our model when compared to two different
titanium nail configurations. Apart from in cases of known allergy or planned
MRI-examinations our results and data from the literature question the use of
titanium nails.
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Langue : ANGLAIS