Biomechanical analysis of hemipelvic deformation after corticospongious bone graft harvest from the posterior iliac crest.
METHODS
The stiffness of the hemipelvis during simulated physiologic loading and the bone deformation in the remaining posterior ilium after the harvest of increasing sizes of corticospongious bone graft were compared with values in intact bone.


OBJECTIVE
To quantify the biomechanical effects of the removal of bone grafts from the posterior ilium and to relate the size of graft removed to the stiffness of the hemipelvis and deformation of the remaining bone.


BACKGROUND
Bone fractures and pelvic instability have been reported to complicate graft harvest from the posterior iliac crest. There is no quantitative data relating graft size to the mechanical properties of the remaining ilium.


METHODS
Seven cadaveric hemipelves were loaded with a materials testing machine through the superior sacrum while supported at the acetabulum and stabilized with a cable fixed to the ilium. Force and displacement histories and deformation in the greater sciatic notch were recorded for the intact bone and after removal of corticospongious bone graft in 1.5-cm increments from the posterior iliac crest.


RESULTS
If the length of the removed corticospongious bone graft exceeded 3.0 cm, the stiffness of the posterior pelvic ring decreased, and deformation in the remaining bone increased substantially.


CONCLUSIONS
Removal or bone graft in excess of 3 cm from the posterior ilium increases the risk of iatrogenic fatigue fracture.
Varga
E
E
Orthopaedic Biomechanics Research Laboratory, Sunnybrook Health Science Centre, University of Toronto, Ontario, Canada.
Hu
R
R
Hearn
T C
TC
Woodside
T
T
Yang
J P
JP
D016025:Bone Transplantation; D002102:Cadaver; D006801:Humans; D007085:Ilium / Q000473:pathology* / Q000503:physiopathology / Q000637:transplantation*; D010388:Pelvis / Q000503:physiopathology / Q000601:surgery; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology