119. The fractures which occur in the lower extremity of the os
femoris, are of two kinds very different from each other. Sometimes
situated above the condyls, they only separate these from the body
of the bone: at other times, affecting the condyls themselves,
they extend into the very joint. My attention shall at present be
confined exclusively to the latter kind, as the other may, in almost
every respect, be classed with the fractures which have been already
considered. Most authors have neglected to treat of fractures of
this kind, under a distinct head, from a persuasion, that, owing to
their communication with the joint, they ought to be ranked among
complicated fractures, which are known to require a mode of treatment
very different from that employed in such as are simple. But I shall
presently show what regard ought to be paid to this ancient opinion.
120. The division presents itself, in general, under two different
forms: 1st, running obliquely from above downwards, and from within
outwards or from without inwards, it may separate a greater or smaller
portion of one of the condyls from the rest of the bone: 2dly, these
two bony protuberances may be divided from each other by a longitudinal
fracture, meeting another transverse or oblique fracture, which by
either passing through the whole thickness of the bone, separates both
condyls from it, or extending only half way through it, separates but
one of them. The fracture is single in the first case, but double in
the second. The latter occurs in practice more frequently than the
former. Both are usually produced directly, that is, by the immediate
action of external bodies. Yet the following fact seems to evince that
the accident may, possibly at least, arise from a counter stroke.
CASE X. The corpse of a man of forty, was brought into the amphitheatre
of Desault, soon after he became a public teacher. One of the pupils,
on preparing to dissect the body, discovered a preternatural mobility
in one of the condyls. The knee was examined. A double fracture was
found, accompanied by a separation of the two condyls. On inquiry
it was ascertained that the corpse came from the Hotel-Dieu. It
was further discovered, with certainty, that the injured subject,
in jumping through a window, had alighted on his feet, and that he
experienced instantly a severe pain in his knee, and fell on the
ground, unable to support himself.
Here, no doubt but the condyls, by being violently pressed between the
weight of the body and the articulating surfaces of the tibia, had been
fractured by a counter-stroke.
§ XIX.