After the determination of the shear strength and modes of failure of
the capital femoral epiphyseal plates in twenty-five pairs of hips obtained
post mortem from children five days to fifteen years and ten months old,
with the plate intact on one side and with the perichondrial
fibrocartilaginous complex removed on the other, the gross and microscopic
morphology was studied. The shear strength of the human epiphyseal plate
varied with age and was greatly dependent on the surrounding perichondrial
complex in infancy and early childhood, but less so in adolescence. When
this complex was excised, the strength of the epiphyseal plate was
diminished, especially in specimens from younger children. The forces
necessary to cause slipping were found to be within the physiological range
of the force that would be generated in overweight children, suggesting
that purely mechanical factors may play a major role in the etiology of
slipped capital femoral epiphysis.