PELVIC OSTEOTOMY FOR SPASTIC HIP DISLOCATION
ORTHOPAEDIC DEPARTMENT
THE ALFRED I. DUPONT INSTITUTE
WILMINGTON, DELAWARE
Patients who had not had prior muscle release surgery or whose contracture
had reoccurred and limited hip abduction, first had an open complete release
of the adductor longus and brevis, gracilus, and an anterior branch obturator
neurectomy. This was followed with a varus osteotmy using the AO blade
plate as previously described. The chisel was inserted with the goal of
creating 90 to 100 degrees varus neck-shaft angle for non- ambulators and
110 to 120 degree neck-shaft angle for
ambulators. After the femoral osteotomy, care was taken to remove the
whole lesser trocanter including the cartilage cap to provide a complete
release of the iliopsoas for marginal or non- ambulators. For community
ambulators, intermusclar lengthening of the Iliopsoas is performed with
preservation of the lesser trocanter on the proximal fragment. Next, the
proximal fragment is abducted and evaluated under fluoroscopy to document
that the femoral head will reduce into the acetabulum 
.
If it does not reduce, an anterior and medial capsulectomy is performed
through the femoral osteotomy. By abducting the proximal fragment good
visualization of the medial capsule is possible and the aspect of the capsule
which prevents reduction can easily be released. If the femoral head does
reduce with abduction but continues to be unstable in the acetabular with
superior pressure or had windshield wiper movement with 30 degrees of abduction
in the expected range after fixation of the osteotomy or the sourcil of
the acetabulum slopes superiorly or is diffuse, a pelvic osteotomy was
indicated. This was done before fixation of the femoral osteotomy by packing
the femoral site leaving the proximal fragment abducted. An anterior bikini
incision was made just distal to the anterior supior iliaec spine. The
iliac apophysis was split and the lateral aspect of the ileum only was
subperiosteally exposed down to the hip capsule. The interval between sartorius
and fascia lata was developed down to the anterior inferior spine. The
interval between the iliac spines was incised and the capsule
was identified from the inferior iliac spine all the way posterior to
the triradiate cartilage. The posterior dissection was performed using
a cobb elevator, however the sciatic notch is not entered. The posterior
dissection is all inferior to the sciatic notch. Using a 4- 6 mm wide straight
osteotome with constant fluoroscopic control the initial cut is made directly
lateral to medial starting 3- 5 mm above the osseous corner
of the acetabulum directed medially to the middle of the triradiate
cartilage. The cut is than completed anteriorly with the anterior 1 cm
cutting across both tables of the ileum. The cut is continued posteriorly
by continuing to aim at the center of the triradiate cartilage making sure
that all of the posterior cortex is cut down to the triradiate. 
With the osteotome in the most posterior aspect of the osteotomy, the osteotomy
should easily open. A tricortical bank bone graft is cut into a triangle
10 - 15 mm tall and long enough to be just short of the triradiate cartilage.
The
posterior graft is inserted first trying to get it directed anteriorly
so there is more opening posterior. 
A second smaller anterior graft is next inserted. The position of the hip
is now checked under fluoroscopy to make sure that it remains stable with
movement in the expected range after fixation of the femoral osteotomy.
After this the femoral osteotomy is reduced and held manually with the
hip flexed 90 degrees and the knee fully extended. The femur is shortened
so the osteotomy has no compression force in the straight leg raising position.
This usually requires 2- 6 cm of further femoral shortening. If the patient
is a very function ambulator than distal hamstring lengthening should be
done first so less femoral shortening is required. The femoral osteotomy
is next fixed with an AO blade plate. 
Careful attention is given to placing the femur in zero to 15 degrees anteversion
so the knee should rest in external rotation with the hip extended and
the hip must come to neutral rotation at 90 degrees of knee and hip flexion
for comfort and ease of sitting. Retroversion must be avoided. If the contra-
lateral hip is also subluxated or dislocated the same procedure is performed
at the same setting. If the opposite leg had an abduction contracture or
was more than 2 cm longer, a concurrent varus osteotomy was performed to
provide for symmetrical hip motion and leg length.
An xray at the conclusion of the procedure should show well reduced
hips
which are symmetrical and well covered. The windswept position pre-operatively
if
present must be converted to as symmetrical a position post-operatively
as possible. 
The outcome of this procedure is reliable
and good on follow-up.
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.
If it does not reduce, an anterior and medial capsulectomy is performed
through the femoral osteotomy. By abducting the proximal fragment good
visualization of the medial capsule is possible and the aspect of the capsule
which prevents reduction can easily be released. If the femoral head does
reduce with abduction but continues to be unstable in the acetabular with
superior pressure or had windshield wiper movement with 30 degrees of abduction
in the expected range after fixation of the osteotomy or the sourcil of
the acetabulum slopes superiorly or is diffuse, a pelvic osteotomy was
indicated. This was done before fixation of the femoral osteotomy by packing
the femoral site leaving the proximal fragment abducted. An anterior bikini
incision was made just distal to the anterior supior iliaec spine. The
iliac apophysis was split and the lateral aspect of the ileum only was
subperiosteally exposed down to the hip capsule. The interval between sartorius
and fascia lata was developed down to the anterior inferior spine. The
interval between the iliac spines was incised and the capsule 
