of injury, the
finding of the smooth broad end of the diaphysis in the popliteal
space or on the front of the thigh, according to the displacement,
usually serve to establish the diagnosis. The X-rays afford reliable
information as to the position of the fragments. Pressure on the
popliteal vessels is a serious aggravation of the injury, and adds
greatly to the difficulties of treatment.

[Illustration: FIG. 82.--Radiogram of Separation of Lower Epiphysis of
Femur, with backward displacement of the diaphysis; pressure on
popliteal vessels caused sloughing of calf.]

[Illustration: FIG. 83.--Separation of Lower Epiphysis of Femur, with
fracture of lower end of diaphysis.]

The treatment is the same as for supra-condylar fracture, but, owing
to the serious disability that follows on incomplete reduction, it may
be necessary to have recourse to operation. After an epiphysial
separation, the growth of the limb is sometimes, although not always,
interfered with.

#Either condyle# may be broken off without the continuity of the shaft
being interrupted, by a direct blow or fall on the knee, or by violent
twisting of the leg. The separated condyle may not be displaced, or it
may be pushed upwards or rotated on its transverse axis.

There is broadening of the knee but no shortening of the thigh, and
the ecchymosis, crepitus, and pain are localised to the affected side
of the joint; the knee can usually be moved towards the injured side
in a way that is characteristic. If allowed to unite with the condyle
displaced, the articular surface is oblique and bow- or knock-knee
results.

If there is difficulty in replacing the broken condyle and maintaining
it in position, it may be fixed by means of a steel nail inserted
through the skin.

FRACTURE OF THE UPPER END OF THE TIBIA

#Fracture of the head of the tibia# is a comparatively rare injury. It
may result from a direct blow, such as the kick of a horse, or from
indirect forms of violence, and the line of fracture may be
transverse or oblique. Occasionally the distal fragment is impacted
into the proximal and comminutes it. In oblique fracture a gliding
displacement is liable to occur and cause bow- or knock-knee.
Transverse fracture of the head of the fibula sometimes accompanies
fracture of the head of the tibia, and there is always considerable
effusion into the knee-joint. One or other of the condyles may be
chipped off by forcible adduction or abduction at the knee