Preoperative Assessment and Preparation
A plain anteroposterior radiograph of the pelvis confirms a high-riding
dislocation of the femoral head. In the original series, unilateral skin tape
traction was applied to the affected side for two weeks, at which time a
repeat radiograph was made to confirm that the femoral head had descended to a
position opposite the acetabulum. Skeletal traction was sometimes required in
older children to achieve this end point. We no longer employ skin traction;
rather, a simultaneous shortening osteotomy of the femur is done in children
who are more than three years of age when the femoral head persists in a
high-riding position.
Operative Set-up
The child is positioned supine on a radiolucent operating table under
general anesthesia. An appropriately sized bolster is placed under the
ipsilateral hemithorax to facilitate skin preparation and draping
(Fig. 2).
Operative Protocol
A percutaneous adductor tenotomy is first performed and the skin wound is
closed.
An anterior approach to the hip joint is used. An oblique
"bikini-line skin incision" is made in the groin crease, centered
on and 1 cm distal to the anterior superior iliac spine
(Fig. 3). It should continue
inferiorly for a distance sufficient to allow adequate distal exposure of the
capsule and the transverse acetabular ligament. This can nonetheless be
achieved through an incision that sweeps medially below the anterior inferior
iliac spine rather than one that has a vertical component inferiorly. The
latter produces an ugly scar.
The fascia at the interval between the sartorius and the tensor fascia
femoris is incised longitudinally, and the muscles are separated. This
interval is reliably located immediately below the anterior inferior iliac
spine, but some surgeons find it easier to identify the interval more distally
where it is more easily palpated. A leash of vessels at the inferior end of
the wound, marking the ascending branch of the medial circumflex femoral
artery, requires cauterization to provide adequate distal exposure. The rectus
femoris tendon is dissected free from the underlying joint capsule, is tagged
distally with a suture for later repair, and is cut to leave a proximal stump
while the muscle is retracted distally. The iliac apophysis is split evenly
with a scalpel from the anterior inferior iliac spine to the midpoint of the
iliac crest (Fig. 4). The iliac
apophysis is a thick layer in this age group, and a large blade may facilitate
the development of equal apophyseal flaps. The periosteum is elevated in a
continuous sheet from the outer and inner tables of the ilium with a
long-handled elevator. In younger children, this layer can initially be simply
peeled off the crest with a sponge or swab. Care must be taken to stay within
the periosteal sheath at the greater sciatic notch in order to avoid injuring
the sciatic nerve and the superior gluteal artery or vein. The sciatic notch
and subperiosteal spaces thus created are packed with sponges.
If the full width of the direct head of the rectus femoris has been
sectioned and retracted distally, a distinct plane opens up over the capsule.
The reflected head of the rectus femoris is a useful guide to this interval,
which is developed proximally between the dislocated femoral head and the
gluteal muscles. These are partially adherent to the false capsule. Once this
plane has been developed to the apex of the femoral head, the pouch thus
created is connected with the subperiosteal space of the outer table of the
ilium. This completes the exposure of the superior capsule. Inferiorly, a
blunt periosteal elevator is used to gently develop the interval between the
capsule and the psoas tendon and muscle.
Once this plane has been cleared, the psoas tendon, which is always tight
and overlying the introitus to the true socket, is released over the pelvic
brim to facilitate reduction and to lessen the pressure on the reduced femoral
head. The subperiosteal dissection of the inner table of the ilium is followed
distally and inferomedially to the anterior inferior iliac spine, bringing
into direct view the fibers of the iliopsoas over the pelvic brim. The
periosteum that was previously stripped from the inner table of the ilium is
incised longitudinally to facilitate this exposure. The psoas tendon lies deep
to these fibers and is brought into the wound with a forceps or closed,
curved, blunt-tipped scissors. With care being taken to ensure that the
dissection is deep to the femoral nerve, the tendon is sectioned sharply, with
the muscle fibers being left intact. Hip flexion facilitates retraction of the
tendon into the wound, and the ability to place a finger over the pelvic brim
as the hip is brought into extension is useful to confirm an adequate
release.
The capsule of the hip joint is incised 1 cm distal and parallel to the
edge of the acetabular labrum (Fig.
5). Once the femoral head is visualized, additional incisions are
made over a MacDonald elevator to protect the articular cartilage. The
capsular incision extends medially to the depth of the acetabulum so that the
transverse acetabular ligament can be released under direct vision. A surgical
headlamp is very helpful for achieving adequate visualization in order to
avoid damaging the articular cartilage, as standard operating room overhead
lighting is often inadequate. The ligamentum teres, which is usually
hypertrophied and therefore excised, can be sectioned from the femoral head
and grasped with a Kocher clamp (Fig.
6). Pulling up on this structure provides a guide down to the
transverse acetabular ligament. The capsular incision is then extended
proximally until it is level with the top of the dislocated femoral head. This
facilitates gentle extraction of the femoral head from the false capsule and
overlying abductor muscles.
The hip may now be reduced into the true acetabulum without undue pressure
in the younger child, particularly one who is less than three years of age.
Neither excision nor incision of the cartilaginous labrum is ever required
because doing so will compromise the future development of the
acetabulum4. In the
older child, a shortening osteotomy of the femur is usually required if
preoperative traction has been omitted; if so, the hip wound is packed with
sponges at this juncture.
The femoral osteotomy is performed through a separate straight longitudinal
incision from the tip of the greater trochanter along the proximal quarter of
the femur. Separate pelvic and femoral incisions leave less skin scarring than
a single incision does but require an adequate intervening tissue bridge. The
femur is exposed subperiosteally, and a four-hole straight plate of
appropriate size is selected. The plate is attached to the femur with two
screws that are inserted proximal to the proposed osteotomy site. The proximal
edge of the plate is placed at the level of the apophyseal line of the greater
trochanter. A transverse osteotomy is then performed with an oscillating saw
either with the plate in situ or temporarily removed. A second osteotomy,
parallel to the first, is made distally, with the removal of sufficient bone
to permit reduction of the femoral head without undue pressure. Conservative
initial cuts are recommended to avoid excessive shortening, which may
compromise hip joint stability; the plate can be repositioned after the
removal of more bone if necessary. Typically, shortening of 1 to 2 cm is
sufficient. Judicious derotation is performed to leave a minimum of 25° of
femoral anteversion; excessive derotation combined with an innominate
osteotomy may lead to posterior dislocation of the femoral head
postoperatively. When appropriate tension through the hip joint has been
established and the hip is stable in slight abduction and internal rotation,
the plate is fixed distally with two screws.
We use a straight plate rather than an angled blade-plate with medial
offset. Medial displacement of the distal osteotomy fragment may lead to
abutment of the femur against the ischium and may predispose the hip to
postoperative lateral subluxation. Substantial femoral neck valgus is seldom
if ever present in cases of primarily treated developmental hip dislocation;
if varus angulation is desired after derotation, a straight plate applied to
the curved subtrochanteric portion of the femur will produce 5° to 10°
of varus. A preoperative plain anteroposterior radiograph of the pelvis with
the hips internally rotated will usually confirm that any observed valgus
angulation is most typically only apparent and due to excessive femoral neck
anteversion.
The femoral wound is closed, and the pack is then removed from the hip
wound. The femoral head is reduced into the acetabulum under the labrum. An
incision is made in the distal capsule, perpendicular to the first incision
and just lateral to the anterior inferior iliac spine. This incision is
continued parallel to the femoral neck to create a T-shaped capsulotomy
(Fig. 7). The redundant
proximal portion of the lateral flap of capsule is excised. As the hip is
reduced and rotated internally, the triangular defect created in the capsule
is closed, converting the "T" to a "V"
(Fig. 8). Commencing from
medial to lateral, heavy, nonabsorbable, figure-of-eight sutures are placed in
the apposed capsular edges to hold the femoral head internally rotated in the
true acetabulum and to obliterate the false compartment into which it might
otherwise redislocate (Figs. 9-A and
9-B). The stability of the reduction is now much improved, but the
sutures are not tied until after the innominate osteotomy is performed.
The sponges are removed from the subperiosteal spaces and sciatic notch,
into which a suitable pair of blunt-tipped lever retractors are placed. Again,
diligence is required to stay within the subperiosteal space and to minimize
bleeding. We use Rang
retractors5 (Jantek
Engineering, Pasa Robles, California), which are inserted into the sciatic
notch with their spadeshaped tips interlocking
(Figs. 10-A and 10-B). These
retractors create a protected channel through which it is easy to pass a Gigli
saw without snagging or otherwise violating the surrounding soft tissues. This
can usually be done manually, although a right-angle clamp may facilitate this
maneuver, with the saw passing from medial to lateral. The cut is made to exit
at the proximal margin of the anterior inferior iliac spine, with the saw
being moved perpendicular to the iliac crest rather than perpendicular to the
operating room table. Correct placement of the handles of the Rang retractors
helps to guide the course of the Gigli saw through the ilium
(Fig. 11), and they should be
kept apart to prevent binding of the saw teeth. Lowering the table prior to
sawing is helpful; one should not be perturbed if the saw exits the bone and
saw handles under tension at the end of the cut.
After completion of the osteotomy, the distal fragment tends to displace
posteriorly. This is overcome by packing a sponge into the sciatic notch
posterior to the distal fragment with a periosteal elevator. A triangularly
shaped bone graft is then removed from the iliac crest with an oscillating
saw. The base of the triangular graft is the distance between the anterior
superior and anterior inferior iliac spines; this will reliably produce
15° of lateral and 25° of anterior cover. The proximal fragment is
grasped with a towel clip to steady it only; there should be no displacement
of the proximal fragment. A second towel clip, with the tentacles placed well
posteriorly near the greater sciatic notch, grasps the distal fragment to
rotate it downward and forward in line with the ilium. The rotation occurs
about the mobile symphysis pubis. In this manner, the osteotomy site is opened
anteriorly but is kept closed posteriorly and the distal fragment must not be
permitted to displace posteriorly. Similarly, it must not be spread apart with
distraction instruments; this will produce iliac lengthening (and therefore
limb lengthening) rather than rotation and redirection of the acetabulum. The
bone graft is shaped with bone cutters to fit into the osteotomy site
(Fig. 12) and is secured with
two heavy threaded Kirschner wires or Steinmann pins that are inserted under
image-intensifier guidance. The first pin is drilled through the proximal
fragment, across the graft, and well into the distal fragment so that the tip
is just proximal to the triradiate cartilage, posterior and medial to the
acetabulum. As the capsulorrhaphy sutures have not yet been tied, a finger may
be inserted into the acetabulum to confirm that the pin has not penetrated the
joint. A second threaded wire is inserted parallel to the first, and its
position is confirmed with additional imaging.
Secure hip reduction is confirmed before the previously-placed
capsulorrhaphy sutures are tied with the leg held in 20° each of internal
rotation, abduction, and flexion (Fig.
13). The previously tagged distal stump of the rectus femoris
tendon is sutured to its proximal stump at the anterior inferior iliac spine.
The iliac apophysis is reapproximated over the iliac crest with a piercing
towel clip and is carefully repaired with heavy interrupted (number-1)
absorbable sutures. The fascia over the interval between the tensor fascia
femoris and the sartorius is similarly closed. The threaded Kirschner wires
are cut just proud of the repaired iliac apophysis for ease of subsequent
removal. The subcutaneous tissue is closed with a continuous absorbable suture
as is the skin in a subcuticular fashion.
A well-padded single hip spica cast is applied with the hip in 20° of
flexion, abduction, and internal rotation. The cast extends from the nipple
line to just proximal to the ipsilateral ankle, leaving generous space for the
perineum, with a hole cut over the upper abdomen for comfort of feeding.
Careful molding over the posterior aspect of the greater trochanter
discourages posterior subluxation of the femoral head
(Fig. 14). Static imaging of
the hip with fluoroscopy is used to confirm an adequate reduction and
placement of the innominate osteotomy and pins.
A limited transverse-cut computed tomography or magnetic resonance imaging
scan is done the day following surgery to confirm maintenance of reduction.
Because the child is immobilized in a hip spica cast, additional general
anesthesia is not required for imaging.
The cast need not be excessively restrictive, which we believe is important
in preventing postoperative hip stiffness, so the contralateral thigh is
intentionally not incorporated in the cast, and the ipsilateral foot and ankle
may move freely. Weight-bearing in the cast is not permitted, but the child is
allowed to crawl and scoot on the floor. The cast is removed six to eight
weeks postoperatively, and gradual return to normal activity is permitted,
although no specific therapy is prescribed. In fact, the child typically has a
mild internal rotation and abduction contracture, which protects the stability
of the hip and resolves spontaneously in two to three months. If there was
concern intraoperatively about stability of the hip following the
capsulorrhaphy, then abduction casts with a spreader bar may be applied for an
additional four weeks. These permit free flexion and extension of the hip but
prevent adduction.
CRITICAL CONCEPTSINDICATIONS:Open Reduction and Innominate OsteotomyDevelopmental dislocation in a patient who is more than eighteen months of
age at the time of presentation.The risk of residual dysplasia at skeletal maturity (Severin grade III or
IV) is 35% after successful open or closed reduction at this age and
approaches 50% after twenty-four months of
age6. Innominate
osteotomy is performed through the same exposure for open reduction and adds
relatively little risk to the procedure. We therefore recommend simultaneous
innominate osteotomy at the time of the open reduction to avoid a later major
secondary procedure in the majority of children with complete dislocation
presenting at this age.A femoral shortening osteotomy is generally required after the age of three
years to reduce the pressure on the reduced femoral head; reduction at this
age may otherwise predispose to osteonecrosis of the femoral head.The upper age limit for open reduction of a unilateral dislocation is nine
years; for bilateral dislocations, it is six years.Innominate Osteotomy AlonePersistent dysplasia after previous successful open or closed reduction
(when done before the age of eighteen months).We recommend a one-year period of observation in this younger age group, in
which there is a high rate of spontaneous improvement in the first year after
a successful
reduction7. If the
acetabular index remains increased when the patient reaches preschool age (3.5
to four years), then an innominate osteotomy should be performed. Cutoff
values for the acetabular index at which to intervene have been previously
published6. The
individual surgeon must select a cutoff and operate for a high, medium, or low
risk of persisting acetabular dysplasia at skeletal maturity according to his
or her philosophy regarding the risk of surgery as compared with the risk of
early-onset osteoarthritis. However, residual acetabular dysplasia must be
corrected prior to the appearance of secondary changes to the acetabulum such
as widening of the acetabular teardrop. Once these changes appear, they
rapidly progress and become irreversible, thereby compromising the future
function of the hip joint.If there is femoral head subluxation after a previous successful open or
closed reduction, then immediate innominate osteotomy is indicated, together
with an open capsulorrhaphy to ensure concentric reduction of the femoral
head.CONTRAINDICATIONS:Inability to bring the head of the femur opposite the acetabulum. Femoral
shortening is then indicated.Residual tightness of the adductor and iliopsoas muscles after prior closed
or open reduction. Lengthening of these structures is an integral part of the
innominate osteotomy procedure.Incomplete reduction of the femoral head into the true acetabulum.Incongruity of the hip joint surfaces.Marked limitation of hip joint motion.Neuromuscular conditions with acetabular dysplasia such as cerebral palsy
and myelodysplasia. Typically, the deficiency of the acetabulum in these
conditions is posterior, which would be aggravated rather than improved by an
innominate osteotomy.PITFALLS:Failure to achieve concentric reduction leading to postoperative
dislocation in the cast or persistent subluxation despite the innominate
osteotomy.Failure to ensure gentle reduction, which may subsequently lead to
osteonecrosis. A femoral shortening osteotomy should be performed if
difficulty is encountered reducing the hip without using excessive force.Tying the sutures placed for the capsulorrhaphy prior to completing the
innominate osteotomy. As there is considerable manipulation of the distal
osteotomy fragment containing the acetabulum, an unrecognized intraoperative
redislocation may occur. Also, by leaving the sutures untied, the hip may be
left dislocated during the introduction of the pins and a finger can be placed
in the acetabulum to check for joint penetration.Failure to keep the posterior part of the osteotomy closed (at the sciatic
notch) while rotating around the mobile symphysis pubis. The osteotomy will
simply be distracted rather than opened anteriorly, and the distal fragment
may displace posteriorly. Each or a combination of these pitfalls will result
in failure to correct the acetabular dysplasia and lead to limb lengthening,
with an unintended increase in the pressure on the reduced femoral head.AUTHOR UPDATE:Remarkably, the essential components of the surgical technique have not
changed in the fifty years since the innominate osteotomy was introduced.Preoperative traction is no longer used for the child who is less than
three years of age, and skeletal traction has been replaced by femoral
shortening in the child who is more than three years of age. The rate of
osteonecrosis of the femoral head in the original series was
low3 but has not
increased since the abandonment of preoperative skeletal traction. A secondary
benefit of overhead skin traction was to stretch the contracted hamstring
muscles, which may otherwise force the femoral head out of the acetabulum,
despite capsulorrhaphy, if the knee is fully extended. We are therefore
careful to keep both the hip and the knee flexed 20° to 30° while
tying the capsulorrhaphy sutures, through wound closure, and until the spica
cast has fully set. We now use fiberglass casting material instead of plaster
of Paris.Modern imaging (computed tomography or magnetic resonance imaging) with
cross-sectional cuts to confirm the concentricity of the reduction
postoperatively now provides us with greater certainty than can be achieved
with use of plain radiographs. Such imaging can be performed on the first
postoperative day and at subsequent times if necessary without general
anesthetic or sedation while the child remains immobilized in the hip spica
cast.The addition of Rang retractors since the original cohort of patients was
treated has greatly facilitated the ease and safety of passing the Gigli saw
through the sciatic
notch5. We now use
them routinely.We still cleanly incise (split) the iliac apophysis from the anterior
inferior iliac spine to almost the midpoint of the iliac crest because
follow-up at forty-five years has confirmed minimal if any clinical or
radiographic deformity of the iliac crest and excellent abductor strength. We
cannot recommend the so-called iliac crest-sparing incision because it
interferes with the blood and nerve supply to the hip abductors, causes
excessive blood loss, and damages the origin of the abductor muscles, leading
to a persistent limp.Many modifications have been proposed to the original technique described
for innominate osteotomy. We do not recommend placing a notch in the proximal
fragment of the ilium for the posterior margin of the distal fragment to
achieve additional stability unless the procedure is a revision. In this
situation, the modification can be helpful to shorten the ilium. It can also
lead to excessive anterior displacement and possible hip impingement, so we do
not recommend it for routine cases. Furthermore, because of the contour of the
ilium, the distal fragment never fits very well into the notch placed in the
proximal fragment.
CRITICAL CONCEPTS
INDICATIONS:
Open Reduction and Innominate Osteotomy
Developmental dislocation in a patient who is more than eighteen months of
age at the time of presentation.The risk of residual dysplasia at skeletal maturity (Severin grade III or
IV) is 35% after successful open or closed reduction at this age and
approaches 50% after twenty-four months of
age6. Innominate
osteotomy is performed through the same exposure for open reduction and adds
relatively little risk to the procedure. We therefore recommend simultaneous
innominate osteotomy at the time of the open reduction to avoid a later major
secondary procedure in the majority of children with complete dislocation
presenting at this age.A femoral shortening osteotomy is generally required after the age of three
years to reduce the pressure on the reduced femoral head; reduction at this
age may otherwise predispose to osteonecrosis of the femoral head.The upper age limit for open reduction of a unilateral dislocation is nine
years; for bilateral dislocations, it is six years.
Developmental dislocation in a patient who is more than eighteen months of
age at the time of presentation.
The risk of residual dysplasia at skeletal maturity (Severin grade III or
IV) is 35% after successful open or closed reduction at this age and
approaches 50% after twenty-four months of
age6. Innominate
osteotomy is performed through the same exposure for open reduction and adds
relatively little risk to the procedure. We therefore recommend simultaneous
innominate osteotomy at the time of the open reduction to avoid a later major
secondary procedure in the majority of children with complete dislocation
presenting at this age.
A femoral shortening osteotomy is generally required after the age of three
years to reduce the pressure on the reduced femoral head; reduction at this
age may otherwise predispose to osteonecrosis of the femoral head.
The upper age limit for open reduction of a unilateral dislocation is nine
years; for bilateral dislocations, it is six years.
Innominate Osteotomy Alone
Persistent dysplasia after previous successful open or closed reduction
(when done before the age of eighteen months).We recommend a one-year period of observation in this younger age group, in
which there is a high rate of spontaneous improvement in the first year after
a successful
reduction7. If the
acetabular index remains increased when the patient reaches preschool age (3.5
to four years), then an innominate osteotomy should be performed. Cutoff
values for the acetabular index at which to intervene have been previously
published6. The
individual surgeon must select a cutoff and operate for a high, medium, or low
risk of persisting acetabular dysplasia at skeletal maturity according to his
or her philosophy regarding the risk of surgery as compared with the risk of
early-onset osteoarthritis. However, residual acetabular dysplasia must be
corrected prior to the appearance of secondary changes to the acetabulum such
as widening of the acetabular teardrop. Once these changes appear, they
rapidly progress and become irreversible, thereby compromising the future
function of the hip joint.If there is femoral head subluxation after a previous successful open or
closed reduction, then immediate innominate osteotomy is indicated, together
with an open capsulorrhaphy to ensure concentric reduction of the femoral
head.
Persistent dysplasia after previous successful open or closed reduction
(when done before the age of eighteen months).
We recommend a one-year period of observation in this younger age group, in
which there is a high rate of spontaneous improvement in the first year after
a successful
reduction7. If the
acetabular index remains increased when the patient reaches preschool age (3.5
to four years), then an innominate osteotomy should be performed. Cutoff
values for the acetabular index at which to intervene have been previously
published6. The
individual surgeon must select a cutoff and operate for a high, medium, or low
risk of persisting acetabular dysplasia at skeletal maturity according to his
or her philosophy regarding the risk of surgery as compared with the risk of
early-onset osteoarthritis. However, residual acetabular dysplasia must be
corrected prior to the appearance of secondary changes to the acetabulum such
as widening of the acetabular teardrop. Once these changes appear, they
rapidly progress and become irreversible, thereby compromising the future
function of the hip joint.
If there is femoral head subluxation after a previous successful open or
closed reduction, then immediate innominate osteotomy is indicated, together
with an open capsulorrhaphy to ensure concentric reduction of the femoral
head.
CONTRAINDICATIONS:
Inability to bring the head of the femur opposite the acetabulum. Femoral
shortening is then indicated.Residual tightness of the adductor and iliopsoas muscles after prior closed
or open reduction. Lengthening of these structures is an integral part of the
innominate osteotomy procedure.Incomplete reduction of the femoral head into the true acetabulum.Incongruity of the hip joint surfaces.Marked limitation of hip joint motion.Neuromuscular conditions with acetabular dysplasia such as cerebral palsy
and myelodysplasia. Typically, the deficiency of the acetabulum in these
conditions is posterior, which would be aggravated rather than improved by an
innominate osteotomy.
Inability to bring the head of the femur opposite the acetabulum. Femoral
shortening is then indicated.
Residual tightness of the adductor and iliopsoas muscles after prior closed
or open reduction. Lengthening of these structures is an integral part of the
innominate osteotomy procedure.
Incomplete reduction of the femoral head into the true acetabulum.
Incongruity of the hip joint surfaces.
Marked limitation of hip joint motion.
Neuromuscular conditions with acetabular dysplasia such as cerebral palsy
and myelodysplasia. Typically, the deficiency of the acetabulum in these
conditions is posterior, which would be aggravated rather than improved by an
innominate osteotomy.
PITFALLS:
Failure to achieve concentric reduction leading to postoperative
dislocation in the cast or persistent subluxation despite the innominate
osteotomy.Failure to ensure gentle reduction, which may subsequently lead to
osteonecrosis. A femoral shortening osteotomy should be performed if
difficulty is encountered reducing the hip without using excessive force.Tying the sutures placed for the capsulorrhaphy prior to completing the
innominate osteotomy. As there is considerable manipulation of the distal
osteotomy fragment containing the acetabulum, an unrecognized intraoperative
redislocation may occur. Also, by leaving the sutures untied, the hip may be
left dislocated during the introduction of the pins and a finger can be placed
in the acetabulum to check for joint penetration.Failure to keep the posterior part of the osteotomy closed (at the sciatic
notch) while rotating around the mobile symphysis pubis. The osteotomy will
simply be distracted rather than opened anteriorly, and the distal fragment
may displace posteriorly. Each or a combination of these pitfalls will result
in failure to correct the acetabular dysplasia and lead to limb lengthening,
with an unintended increase in the pressure on the reduced femoral head.
Failure to achieve concentric reduction leading to postoperative
dislocation in the cast or persistent subluxation despite the innominate
osteotomy.
Failure to ensure gentle reduction, which may subsequently lead to
osteonecrosis. A femoral shortening osteotomy should be performed if
difficulty is encountered reducing the hip without using excessive force.
Tying the sutures placed for the capsulorrhaphy prior to completing the
innominate osteotomy. As there is considerable manipulation of the distal
osteotomy fragment containing the acetabulum, an unrecognized intraoperative
redislocation may occur. Also, by leaving the sutures untied, the hip may be
left dislocated during the introduction of the pins and a finger can be placed
in the acetabulum to check for joint penetration.
Failure to keep the posterior part of the osteotomy closed (at the sciatic
notch) while rotating around the mobile symphysis pubis. The osteotomy will
simply be distracted rather than opened anteriorly, and the distal fragment
may displace posteriorly. Each or a combination of these pitfalls will result
in failure to correct the acetabular dysplasia and lead to limb lengthening,
with an unintended increase in the pressure on the reduced femoral head.
AUTHOR UPDATE:
Remarkably, the essential components of the surgical technique have not
changed in the fifty years since the innominate osteotomy was introduced.Preoperative traction is no longer used for the child who is less than
three years of age, and skeletal traction has been replaced by femoral
shortening in the child who is more than three years of age. The rate of
osteonecrosis of the femoral head in the original series was
low3 but has not
increased since the abandonment of preoperative skeletal traction. A secondary
benefit of overhead skin traction was to stretch the contracted hamstring
muscles, which may otherwise force the femoral head out of the acetabulum,
despite capsulorrhaphy, if the knee is fully extended. We are therefore
careful to keep both the hip and the knee flexed 20° to 30° while
tying the capsulorrhaphy sutures, through wound closure, and until the spica
cast has fully set. We now use fiberglass casting material instead of plaster
of Paris.Modern imaging (computed tomography or magnetic resonance imaging) with
cross-sectional cuts to confirm the concentricity of the reduction
postoperatively now provides us with greater certainty than can be achieved
with use of plain radiographs. Such imaging can be performed on the first
postoperative day and at subsequent times if necessary without general
anesthetic or sedation while the child remains immobilized in the hip spica
cast.The addition of Rang retractors since the original cohort of patients was
treated has greatly facilitated the ease and safety of passing the Gigli saw
through the sciatic
notch5. We now use
them routinely.We still cleanly incise (split) the iliac apophysis from the anterior
inferior iliac spine to almost the midpoint of the iliac crest because
follow-up at forty-five years has confirmed minimal if any clinical or
radiographic deformity of the iliac crest and excellent abductor strength. We
cannot recommend the so-called iliac crest-sparing incision because it
interferes with the blood and nerve supply to the hip abductors, causes
excessive blood loss, and damages the origin of the abductor muscles, leading
to a persistent limp.Many modifications have been proposed to the original technique described
for innominate osteotomy. We do not recommend placing a notch in the proximal
fragment of the ilium for the posterior margin of the distal fragment to
achieve additional stability unless the procedure is a revision. In this
situation, the modification can be helpful to shorten the ilium. It can also
lead to excessive anterior displacement and possible hip impingement, so we do
not recommend it for routine cases. Furthermore, because of the contour of the
ilium, the distal fragment never fits very well into the notch placed in the
proximal fragment.
Remarkably, the essential components of the surgical technique have not
changed in the fifty years since the innominate osteotomy was introduced.
Preoperative traction is no longer used for the child who is less than
three years of age, and skeletal traction has been replaced by femoral
shortening in the child who is more than three years of age. The rate of
osteonecrosis of the femoral head in the original series was
low3 but has not
increased since the abandonment of preoperative skeletal traction. A secondary
benefit of overhead skin traction was to stretch the contracted hamstring
muscles, which may otherwise force the femoral head out of the acetabulum,
despite capsulorrhaphy, if the knee is fully extended. We are therefore
careful to keep both the hip and the knee flexed 20° to 30° while
tying the capsulorrhaphy sutures, through wound closure, and until the spica
cast has fully set. We now use fiberglass casting material instead of plaster
of Paris.
Modern imaging (computed tomography or magnetic resonance imaging) with
cross-sectional cuts to confirm the concentricity of the reduction
postoperatively now provides us with greater certainty than can be achieved
with use of plain radiographs. Such imaging can be performed on the first
postoperative day and at subsequent times if necessary without general
anesthetic or sedation while the child remains immobilized in the hip spica
cast.
The addition of Rang retractors since the original cohort of patients was
treated has greatly facilitated the ease and safety of passing the Gigli saw
through the sciatic
notch5. We now use
them routinely.
We still cleanly incise (split) the iliac apophysis from the anterior
inferior iliac spine to almost the midpoint of the iliac crest because
follow-up at forty-five years has confirmed minimal if any clinical or
radiographic deformity of the iliac crest and excellent abductor strength. We
cannot recommend the so-called iliac crest-sparing incision because it
interferes with the blood and nerve supply to the hip abductors, causes
excessive blood loss, and damages the origin of the abductor muscles, leading
to a persistent limp.
Many modifications have been proposed to the original technique described
for innominate osteotomy. We do not recommend placing a notch in the proximal
fragment of the ilium for the posterior margin of the distal fragment to
achieve additional stability unless the procedure is a revision. In this
situation, the modification can be helpful to shorten the ilium. It can also
lead to excessive anterior displacement and possible hip impingement, so we do
not recommend it for routine cases. Furthermore, because of the contour of the
ilium, the distal fragment never fits very well into the notch placed in the
proximal fragment.