[Trabecular arch structure of the upper end of femur and its biomechanical significance in hip fractures: a scanning electron microscopic study].
Scanning electron microscopic study was carried out in cancellous bone tissues of the femoral heads of 19 specimens. The reticular cancellous bone tissues comprised columns and flakes of trabeculae. The arch structure of the cancellous bone in the femoral head assumed round or roundish configuration, the arch structure of the femoral head-neck junction revealed oval outline, while the arch structure of the femoral neck showed narrow oval profile. The fine structure of the trabeculae in the femoral head could be divided into three zones: superficial zone central zone and transitional zone. Under weight-bearing, the central zone suited to sustain the load, while the superficial zone could produce elastic deformation lest fracture should ensue. These structural characteristics endowed the femoral head cancellous bone tissues the capability to bear weight and to absorb the impulsive load. The arch structure of the femoral head-neck junction and the femoral neck facilitates weight-bearing under physiological condition. However, external violence in the form of either adduction or abduction force, would act in a horizontal direction on the long axis of the oval and narrow oval arches. Under such circumstances, the arch structures would lose their mechanical advantage, and thus subcapital or transcervical fracture of femur might take place in aged people suffering from osteoporosis.
Chai
B F
BF
Shanghai Institute of Traumatology and Orthopaedics.
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D005260:Female; D005270:Femur Head / Q000648:ultrastructure*; D005272:Femur Neck / Q000648:ultrastructure*; D006620:Hip Fractures / Q000473:pathology*; D006801:Humans; D008297:Male