Production of spiral fractures in human cadaver long bones by use of a simple torsion machine.
A simple machine was developed so that long bones could be torqued to failure in order to estimate applied moment and study the resulting spiral fracture pattern. Detailed study of the fragments enabled the postulation of an orderly manner of fracture propagation. Twenty-seven embalmed human cadaver femurs were studied. The machine held one end of the bone in a fixed vise and the other in a rotating vise. Spring scales were used to apply force to a bar connected to the rotating vise which allowed for a crude estimation of torsional moment. Male femurs (72.8 yrs old sigma = 11.4) fractured at a mean torque of 106.7 N-m (sigma = 23.8), while female femurs (78.0 yrs old sigma = 6.7) failed at a mean torque of 96.7 N-m (sigma = 39.4). There were no statistically significant differences between the ages (p = 0.20) or the torsional moments at fracture (p = 0.41) for the male and female femurs. Given the similarities in this study population, an eye was turned towards anthropomorphic measurements in order to determine factors that might be indicative of bone strength. Several measurements were made on the fragments especially in the midshaft region. These included six cortex thicknesses, bone depth, width and circumference. Simple statistical analyses were performed.
Porta
D J
DJ
Biology Department, Bellarmine College, Louisville, KY 40205, USA.
Frick
S J
SJ
Kress
T A
TA
Fuller
P M
PM
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D004615:Embalming; D004867:Equipment Design; D005260:Female; D005264:Femoral Fractures / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D013314:Stress, Mechanical