Article

Antegrade femoral nailing has become the standard treatment for
diaphyseal femoral shaft fractures. Concerns linger that improper location of the
nail entry point may lead to iatrogenic fracture and further complications. This
study used finite element analysis to compare the strain magnitude and
distribution resulting from each of two entry points in the proximal femur during
antegrade nailing. METHODS: A finite element model was created from a CT scan of
a 37 year old male femur and of a standard antegrade nail. Using implicit
time-stepping, the nail was inserted through piriformis and trochanteric entry
points and strain was computed at 9 anatomic locations. FINDINGS: The strain
levels were higher overall when inserting a nail through the trochanteric
starting point. The highest strain occurred immediately medial and lateral to the
trochanteric entry point. The posterior greater trochanter also showed very high
strain levels during nail insertion. All strain values for nail insertion through
the piriformis entry point were less than 2000 mum/m. INTERPRETATION: The
trochanteric entry will have a much greater potential of iatrogenic fracture of
the proximal femur during insertion of a nail. Strains with this entry point
exceed the yield level of bone and the repeated loading with the progression of
the nail could cause fissures or fractures. Caution should be taken during
insertion of an antegrade nail when utilizing a lateral trochanteric starting
point secondary to an increased risk of trochanteric fracture and lateral cortex
fracture.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS