tic dislocation.

To keep the head in the socket, the limb must be maintained in the
position of right-angled abduction and external rotation (90 deg.) by a
plaster case, which includes the lower part of the trunk and both
limbs down to the knee. Under the plaster, stockinette drawers are
worn, and the bony prominences are padded with cotton wool. The
plaster should overlap the costal margin. The first case is worn for
two months or more, and is then renewed at shorter intervals, the
degree of abduction being diminished at each renewal until the limbs
are nearly parallel. The child is only kept in bed for a week or two,
and is then allowed up, being provided with a boot and high sole on
the affected side, but should not use crutches. At the end of six
months, by which time the capsule has become tightened up round the
head of the femur, the plaster is given up and massage and exercises
are employed.

_In bilateral cases_ both dislocations are reduced at one sitting if
possible, and a plaster case applied with both thighs abducted and
flexed to a right angle, the so-called "frog position."

In the event of failure to reduce a dislocation at the first attempt,
the limb should be fixed in plaster in the abducted attitude for ten
days or a fortnight, and then another attempt made. The greatest
number of successes in bilateral cases is met with under five years of
age, and in unilateral cases under seven. Reduction may sometimes be
accomplished, however, in older children.

If it is found impossible to restore the head of the femur to the
acetabulum, an attempt should be made by similar manipulations to
wedge it under the long head of the rectus femoris, or, failing this,
below the anterior iliac spine under the sartorius and tensor fasciae
femoris. By thus converting a posterior into an anterior dislocation,
the tilting of the pelvis and the lordosis are greatly diminished.
This procedure, named by Lorenz _anterior transposition of the head of
the femur_, is specially applicable to cases in which relapse has
taken place after reduction, and to those above the age when reduction
should be attempted.

_Reduction by open operation_ may be had recourse to in cases in
which, after several attempts, reduction has failed, or in which
re-dislocation has occurred; it is, however, a serious operation.
Attempts have also been made by means of pegs and other contrivances
to fix the head of the bone and prevent it sliding upwards