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A triple innominate osteotomy can be considered for the older child or adolescent in whom the triradiate cartilage remains open.. Salter stated that the potential for remod-Residual Untr

Although the true incidence of

per-sistent acetabular dysplasia in

adults is unknown, its role as a

sig-nificant cause of premature hip

osteoarthritis is well established.1-4

It is estimated that between 20%

and 50% of cases of degenerative

disease of the hip are secondary to

subluxation or acetabular

dyspla-sia.3 In a classic study of 130

pa-tients with degenerative arthritis of

the hip, Stulberg and Harris2found

that 63 patients (48%) had

underly-ing acetabular dysplasia

Ideally, patients with acetabular

dysplasia and subluxation are

identified and treated in infancy

Failing this, treatment instituted as

early as possible in childhood,

preferably before age 4, will take

maximum advantage of the

inher-ent remodeling capabilities of the

hip joint.5 In the older child or young adult, recognition of persis-tent acetabular dysplasia may at least allow treatment before the onset of irreversible cartilage in-jury and thereby favorably influ-ence an otherwise worrisome nat-ural history

The goal of treatment of patients with persistent acetabular dysplasia

is to forestall or prevent the devel-opment of osteoarthritis and to obviate the need for arthroplasty at

a relatively young age Pelvic oste-otomies can play a central role in this strategy by reorienting the architecture of the pelvis so as to normalize the forces of weight bear-ing To enhance understanding of this important tool in the preven-tion of hip osteoarthritis, we will outline the general categories of

pelvic osteotomies, discuss the indi-cations for their use, and provide a brief technical description of those that are most commonly utilized in current practice

Etiology and Biomechanics of Acetabular Dysplasia

The abnormally steep acetabular roof and the shallow joint surface

Dr Gillingham is Director, Division of Pediatric Orthopedics, Departments of Ortho-pedics and Clinical Investigation, Naval Medical Center, San Diego, Calif; and Assistant Professor of Surgery, Uniformed Services University, Bethesda, Md Dr Sanchez is Head, Department of Orthopedics, Naval Hospital, Twenty-nine Palms, Calif Dr Wenger is Director of Pediatric Orthopedics, Children’s Hospital, San Diego; and Clinical Professor of Orthopedic Surgery, University of California, San Diego.

Reprint requests: Dr Gillingham, Department

of Clinical Investigation, Naval Medical Center San Diego, Suite 5, 34800 Bob Wilson Drive, San Diego, CA 92134-1005.

The Chief, Bureau of Medicine and Surgery, Navy Department, Washington, DC, Clinical Investigation Program, sponsored this report S93-094 as required by NSHSBETHINST 6000.41A The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, the Department of Defense, or the United States Government.

Abstract

Persistent acetabular dysplasia is a well-known cause of premature hip

osteoarthritis In the dysplastic hip, point loading occurs at the edge of the

steep, shallow acetabulum Pelvic osteotomies reduce this load by increasing the

contact area, relaxing the capsule and muscles about the hip, improving the

moment arm of the hip, and normalizing the forces of weight bearing The

orthopaedic surgeon can choose from among a variety of pelvic osteotomies (e.g.,

redirectional, reshaping, and salvage) for the purpose of restoring normal

anato-my and biomechanical forces across the hip joint Treatment of residual

dyspla-sia is based on the patient's age and the presence or absence of congruent hip

reduction A Salter or Pemberton procedure is generally appropriate for a child

between the ages of 2 and 10 A triple innominate osteotomy can be considered

for the older child or adolescent in whom the triradiate cartilage remains open.

After triradiate closure, the Ganz periacetabular osteotomy can be considered in

addition to the triple innominate osteotomy.

J Am Acad Orthop Surg 1999;7:325-337

Dysplasia in Children and Young Adults

CDR Bruce L Gillingham, MC, USN; LCDR Anthony A Sanchez, MC, USNR; and

Dennis R Wenger, MD

that characterize acetabular

dyspla-sia can be due to several causes

Although acetabular dysplasia is

most commonly seen as a

compo-nent of developmental dysplasia of

the hip (DDH), it can also be a

residual of Legg-Perthes disease

and is frequently seen in patients

with neuromuscular diseases, such

as cerebral palsy and

myelomenin-gocele

The importance of a concentric

hip reduction during development

of both components of the hip joint

is well known.5,6 The development

of appropriate acetabular depth

depends in large part on the

stimu-lus of the femoral head pushing into

the triradiate cartilage Conversely,

if the femoral head is to achieve its

normal spherical shape in

adult-hood, it must be well seated within

the acetabulum during infancy and

early childhood Any condition that

interferes with this interdependent

relationship can lead to acetabular

dysplasia Left untreated, a

mean-ingful reduction in the longevity of

the hip joint can result.2

When evaluating an infant or

child with acetabular dysplasia, it is

important to ascertain whether

there is associated hip subluxation

Disruption of ShentonÕs line on a

standing anteroposterior (AP)

radio-graph of the pelvis indicates that

the femoral head is proximally and

laterally subluxated (ShentonÕs

line is created by drawing a line

along the proximal medial femoral

metaphysis and extending onto the

superior border of the obturator

foramen In a normal hip, the line

is an arc of continuous contour.) If

the condition is not treated,

prema-ture joint degeneration and clinical

disability predictably follow The

age at onset of symptoms correlates

well with the severity of the

sublux-ation.2,4,7 The patients with the

most serious disease begin to

expe-rience pain in the second decade;

those with the least serious disease

may reach the fifth decade before

noting symptoms.7 However, even

in moderate cases, functionally dis-abling symptoms can occur during the most vigorous and productive years of life

Less predictable is the effect of acetabular dysplasia without sub-luxation Patients without subluxa-tion are frequently asymptomatic, and osteoarthritis tends to develop much later and less commonly than in patients with subluxation.1 Cooper-man et al1concluded that the usual radiographic indices by which acetabular morphology is character-ized are not predictive of the rate at which osteoarthritis develops in patients with acetabular dysplasia alone In a more recent study of the contralateral hip in patients who had undergone a total hip replace-ment for osteoarthritis secondary to dysplasia, Murphy et al8 noted a

significant (P<0.0001) difference in

standard radiographic indices be-tween patients in whom osteoarthri-tis developed in the opposite hip before age 65 and those in whom it did not Adolescent patients with acetabular dysplasia without associ-ated subluxation should be carefully evaluated for clinical findings, as they (particularly females) are at greater risk than the general popu-lation for the development of clini-cal signs and symptoms of degener-ative hip disease.2

Acetabular dysplasia eventually results in degenerative joint disease due to alterations in load In a study of patients followed up for an average of 29 years after reduction

of a congenitally dislocated hip, Hadley et al9 concluded that over the long term, articular cartilage can tolerate mean contact pressures

of 2 MPa, with an inverse relation-ship between higher pressures and the time needed to develop degen-erative changes In a normal hip, peak acetabular contact pressures may be as high as 10 MPa, depend-ing on activity, but are distributed throughout the entire acetabulum,

with the dome being subjected to the highest pressure and the rim to essentially none.10

In the dysplastic hip, point load-ing occurs at the edge of the steep, shallow acetabulum Pelvic oste-otomies reduce this load by in-creasing contact area, relaxing the capsule and muscles about the hip, and improving the moment arm of the hip.10

Clinical Evaluation History and Physical Examination

The initial evaluation focuses on

a characterization of the patientÕs symptoms, activity level, functional limitations, and expectations The patient with residual dysplasia may

be asymptomatic or may experience only vague discomfort with strenu-ous weight-bearing activities The presence of more extensive com-plaints may suggest that degenera-tive arthritis is already established Most children and teenagers with radiographic evidence of severe subluxation that requires treatment will have no symptoms

Physical examination includes inspection of the extremity for muscle wasting of the quadriceps and gluteus, longitudinal malalign-ment of the limb, and limb-length discrepancy Analysis of the pa-tientÕs gait may reveal a limp or an abductor lurch Palpation of the posterior iliac crest is performed with the patient standing, in order

to detect pelvic obliquity The Trendelenburg test, performed both immediately and after a 20-second delay, allows assessment of the competence and resistance to fatigue of the hip abductors The range of hip motion is carefully documented, with particular atten-tion paid to hip rotaatten-tion and the presence of contractures Pain with active or passive motion sug-gests synovitis or impingement

Pain elicited by internal rotation

of the flexed and adducted hip

may signify the presence of a

de-tached limbus Termed

Òacetabu-lar rim syndromeÓ by Klaue et al,11

this condition is considered to be a

precursor of osteoarthritis of the

hip in patients with acetabular

dysplasia Most children and

ado-lescents, even those with severe

dysplasia, have few, if any,

physi-cal findings

Radiologic Evaluation

A comprehensive radiographic

evaluation is essential to clarify the

degree of deformity before

per-forming a hip osteotomy The

ini-tial plain films should include

weight-bearing (standing) AP,

frog-leg lateral, and abductionÐinternal

rotation views of the pelvis and

hips, as well as a faux profil (French

for Òfalse profileÓ) view of the

affected hip

Analysis of the AP view should

include a qualitative assessment of

ShentonÕs line and the acetabular

sourcil (a term derived from the

French word for ÒeyebrowÓ) As

mentioned previously, a break in

the normal smooth arc of ShentonÕs

line is suggestive of hip subluxation

The appearance of the acetabular

sourcil is a sensitive radiographic

indicator of asymmetric loading of

the hip joint.12 Ordinarily, this

dense subchondral bone appears as

a smooth curve of uniform

thick-ness In the dysplastic hip, lateral

sourcil thickening occurs, which

represents increased focal loading

due to underlying malalignment

(Fig 1) Careful analysis of the

sourcil, especially if there is

side-to-side asymmetry, is an important

tool for the hip surgeon

Measurements of the

center-edge angle of Wiberg,4the adult

acetabular angle of Sharp,13and the

acetabular depth are useful means

of quantitating the severity of the

dysplasia Prior to ossification of

the femoral head, the acetabular

index is generally used to assess acetabular configuration, with nor-mal mean values decreasing to less than 20 degrees by age 24 months (Table 1).14

The abductionÐinternal rotation view neutralizes femoral

antever-sion and allows accurate assess-ment of the true femoral neck-shaft angle In addition, this view simu-lates the coverage possible with a proximal femoral varus osteotomy

A single innominate osteotomy can

be simulated by taking a

radio-Fig 1 Anteroposterior radiograph of the pelvis of an 18-year-old girl with left hip dyspla-sia The right acetabular sourcil appears as a smooth curve of uniform thickness In con-trast, the left sourcil is wider laterally, indicating focal loading.

Table 1 Radiographic Assessment of the Hip *

Children Acetabular index at 3 months, degrees

Acetabular index at 24 months, degrees

Adults Acetabular angle, degrees 25-41 ³43 Acetabular depth, mm 15-27 <15 mm in men,

<14 mm in women Acetabular roof, degrees >0 ²0

Center-edge angle, degrees 24-46 ²20

Normal values represent mean ± 2 SD.

graph with the hip held in 25

de-grees of flexion, 10 dede-grees of

ab-duction, and neutral rotation, with

the x-ray beam directed posteriorly

and caudally 25 degrees.15

The faux profil view, first

de-scribed by Lequesne and de S•ze16

in 1961, is a true lateral view of

the acetabulum made with the

patient standing with the pelvis

rotated 25 degrees toward the

x-ray beam The result is a

center-edge angle-type assessment of

an-terior coverage

Fluoroscopic examination of the

hip in various positions can be a

useful means of gauging the effect

of a proposed osteotomy

Arthrog-raphy is of particular value when

assessing the incompletely ossified

femoral head of a child

The recent advances in

three-dimensional reconstruction of

computed tomographic (CT)

stud-ies have greatly expanded our

understanding of the underlying

pathoanatomy in patients with

residual acetabular dysplasia

This modality is emerging as a valuable preoperative tool for sur-gical decision making and plan-ning.17,18 The three-dimensional display provides superior infor-mation about the fit of the femoral head in the acetabulum, as well as the size, shape, and orientation of the acetabulum This increased detail has clearly demonstrated that acetabular dysplasia is more complex than previously thought

More than just malrotation or maldirection, acetabular dysplasia

is a combination of acetabular maldirection, margin erosion, tor-sion, hypoplasia (localized or global), abnormal shape, and decreased acetabular surface area.19 With this greater under-standing has come an improved ability to match the osteotomy to the type of acetabular deficiency

In addition, comparison of the ini-tial study with one performed postoperatively is a valuable tool

in assessing the success of the osteotomy in reproducing normal

hip architecture and will further refine the surgeonÕs ability to choose the appropriate osteotomy

Treatment Overview

The goal of treatment of the patient with acetabular dysplasia is to establish normal biomechanical forces about the hip joint The means by which this can be accom-plished vary greatly depending on the patientÕs age, the severity of dysplasia, and the morphology of the hip joint (Fig 2)

In the infant and young child, the initial assessment and treat-ment are directed toward ensuring that a concentric hip reduction is present Restoration of hip-joint concentricity may set the stage for profound remodeling The amount

of remodeling that can be relied on

to produce a normal acetabulum and the relationship of remodeling and age have been debated Salter stated that the potential for

remod-Residual

Untreated

Developmental dysplasia of the hip

Patient aged 8 years or older Patient aged

2-8 years

Innominate or Pemberton osteotomy

± proximal femoral osteotomy

Triple innominate osteotomy ± proximal femoral osteotomy

Triple innominate

or periacetabular osteotomy ± proximal femoral osteotomy

Patient aged

18 months

to 3 years

Patient aged

3 years or older

Patient aged

2 to 10 years

Patient aged

10 to 14 years (open triradiate)

Patient aged

14 years or older (closed triradiate)

Consider innominate osteotomy

Shelf procedure, Chiari osteotomy,

or hip fusion

± Femoral

derotational

osteotomy

Femoral derotational

and shortening

osteotomy

Open reduction and

capsulorrhaphy

Innominate osteotomy

Fig 2 Algorithm for treatment of developmental dysplasia of the hip.

eling was greatest at birth and

gradually decreased until age 18

months, when it would no longer be

ensured.20 Harris5concluded, on

the basis of a prospective radiologic

study of 79 dislocated hips, that the

critical point beyond which

restora-tion of hip congruence would not

necessarily result in a normal

ace-tabulum was age 4; the risk of

pro-ducing a moderately or severely

dysplastic acetabulum more than

doubled if hip reduction occurred

beyond this age Thus, in the

18-month-old to 3-year-old child with

acetabular dysplasia due to hip

dis-location, the need for an acetabular

procedure at the time of open

re-duction and capsulorrhaphy is

con-troversial One approach is to

delay a secondary procedure so

that the adequacy of the acetabular

remodeling response can be

as-sessed.21 Most North American

centers, however, are moving

toward following SalterÕs advice to

include the acetabular procedure at

the time of primary treatment in

order to maximize the likelihood

that a normal acetabulum will

ulti-mately develop.20,22

DelBello et al22compared the

re-sults of open reduction alone, open

reduction followed by delayed

innominate osteotomy, and open

reduction plus immediate

innomi-nate osteotomy in a group of older

children with DDH Only the

im-mediate osteotomy group achieved

acetabular indices comparable to

those in normal control subjects

In addition, the hips of 95% of the

patients in the immediate

innomi-nate osteotomy group were

classi-fied as group I or II on the Severin

hip dysplasia scale, compared with

61% in the group of patients who

underwent open reduction alone

and 60% in the delayed innominate

osteotomy group No differences

were found in the rate of

osteo-necrosis of the femoral head, the

estimated surgical blood loss, and

the operative time On the basis of

these findings, the authors recom-mended routine innominate oste-otomy at the time of open reduc-tion for all patients over the age of

18 months

In the child aged 3 years or older, innominate osteotomy is per-formed routinely because of the unpredictable remodeling potential beyond this age.23 In the patient older than age 8, the treatment plan

is based on the symptoms and the severity of the residual dysplasia

In terms of clinical characteristics, patients with DDH vary greatly, ranging from the asymptomatic patient in whom the dysplasia is an incidental finding to the severely incapacitated individual who is in constant pain

Nonoperative therapy is directed toward minimizing excessive point loading across the joint by avoiding unnecessary impact-loading activi-ties, achieving ideal body weight, and maintaining overall physical fitness and muscle tone This can

be supplemented by judicious use

of nonsteroidal anti-inflammatory agents in patients for whom they are not contraindicated While this can be an effective means of treat-ing the symptoms, this strategy does not address the underlying malalignment that is the ultimate cause of osteoarthritis It is impor-tant that parents and older patients understand this, particularly when there are few, if any, symptoms

Paradoxically, these are the pa-tients who may have the most to gain from surgery

The goal and type of surgery chosen depend on the severity of the patientÕs condition In general, there are two groups of patients with residual dysplasia.24 The group amenable to Òreconstruc-tiveÓ procedures are minimally symptomatic and have normal joint congruence and no irreversible car-tilage injury The goal of surgery

in this setting is realignment of the joint surfaces to produce more

nor-mal loading and to forestall the development of osteoarthritis Reconstructive osteotomies include Salter, Pemberton, triple innomi-nate, and periacetabular proce-dures.20,25-27 These procedures have

a relatively predictable outcome

In contrast, the ÒsalvageÓ group demonstrate evidence of irreversible cartilage injury In this setting, the goal of surgery is to relieve pain, delay the inevitable arthroplasty, and improve function in the mean-time The procedures used have a less certain outcome Examples in-clude Chiari28and shelf procedures, often performed on an incongruent, already distorted hip joint

Primary Treatment of Complete Hip Dislocation

If closed treatment has not been effective in a child less than 18 months of age, establishment of normal hip alignment can gener-ally be achieved by open reduc-tion and capsulorrhaphy alone

In patients between 18 months and 3 years of age, immediate in-nominate osteotomy at the time of open reduction maximizes the remodeling potential of the hip

In the presence of excessive fe-moral anteversion or valgus of the femoral neck, a varus derota-tional osteotomy can be included (Fig 3)

We do not advocate the Pember-ton or Dega procedure as part of the treatment for primary dislocation of the hip because both either decrease acetabular volume or change ace-tabular shape The Salter procedure allows redirection but avoids shape

or volume changes

For the child over age 3 years with untreated DDH, the approach

is similar The only difference is the addition of a derotational femoral shortening osteotomy to decrease the compressive forces on the fe-moral head after reduction

Treatment of Residual

Dysplasia

Treatment of residual dysplasia is

based on the patientÕs age and the

presence or absence of congruent

hip reduction In the child between

the ages of 2 and 10 with a

well-reduced hip with anterolateral

acetabular deficiency of a moderate

degree, either a Salter or a

Pember-ton procedure can be performed

Theoretically, with the Pemberton

procedure, the relative relationship

of the cuts in the inner and outer

tables of the ilium can be adjusted

to change the location of the

de-sired augmentation As a

configu-ration-changing osteotomy, the

Pemberton is particularly helpful in

the case of a shallow, capacious, or

ÒwanderingÓ acetabulum

Although many cogent

argu-ments have been made regarding

the relative usefulness of the Salter

and Pemberton procedures, there is

little objective basis for choosing

one over the other The Pemberton

procedure has the advantage that

because the osteotomy is so secure,

fixation pins are not required, and a

second operation to remove pins is

unnecessary If severe coxa valga

or anteversion is present, a femoral osteotomy may have to be added to achieve an anatomically correct radiographic appearance

In the older child or adolescent

in whom the triradiate cartilage remains open (usually over age 10), the triple innominate

osteoto-my26 is our procedure of choice

Although a more extensive dissec-tion is required, this procedure offers the advantage of increased acetabular fragment mobility and thus a wider range of coverage options

After triradiate cartilage closure, the periacetabular osteotomy pop-ularized by Ganz et al27can be con-sidered in addition to a triple oste-otomy The Ganz procedure is technically challenging, but it af-fords nearly unlimited acetabular mobility

In the patient between 2 and 8 years of age with an incongruent joint, a Salter or Pemberton inno-minate osteotomy can be consid-ered provided sufficient remodel-ing potential is present However, the outcome is less predictable than

in the child less than age 4 with

concentric reduction In such cir-cumstances, a femoral osteotomy is commonly added to decompress the joint Beyond age 8, when no remodeling will occur, a salvage osteotomy, such as a Chiari or shelf procedure, is necessary.28,29

Redirectional (Complete) Osteotomies

As their name implies, redirectional osteotomies improve the coverage

of the femoral head by shifting the position of the acetabulum The acetabulum itself remains un-changed Because these procedures involve complete cuts through the innominate bone, fixation is re-quired to maintain the new align-ment until the osteotomy heals In general, there is a direct relation-ship between the technical com-plexity of a redirectional osteotomy and the amount and range of cover-age possible

Single Innominate Osteotomy (Salter)

First described by Salter in 1961,20 the single innominate osteotomy

Fig 3 Bilateral DDH in a 2-year-old girl A, Preoperative AP radiograph of the pelvis B, AP radiograph obtained after staged bilateral

open reductions, proximal femoral varus osteotomies, and innominate osteotomies Ideal graft position is present on the left; undesirable slightly posterior displacement of the osteotomy is present on the right.

remains in widespread use (Fig 4).

Salter conceptualized that

acetabu-lar maldirection was responsible

for the deficiency of femoral head

coverage and designed an osteotomy

to redirect the acetabulum and

thereby provide a stable hip

reduc-tion in the funcreduc-tional weight-bearing

position The amount of acetabular

fragment mobility obtained with

the single innominate osteotomy

depends on rotation and hinging

through the pliable fulcrum of the

pubic symphysis

The primary indication for a

Salter osteotomy is a deficiency of

anterolateral femoral head coverage

in an otherwise concentrically

re-duced hip A shallow acetabulum

is a relative contraindication

Im-provement in the center-edge angle

of 20 to 22 degrees and a 10-degree

improvement in the acetabular

index can be expected.30,31

Skillful exposure and clearing of

the sciatic notch is critical The

Gigli saw cut begins low in the

sci-atic notch and exits just above the

anterior inferior iliac spine The

inferior fragment is pulled distally

and anteriorly with a towel clamp

to provide increased anterolateral

coverage Care should be taken to

prevent displacing the proximal fragment, as this will lead to open-ing of the osteotomy posteriorly at the sciatic notch, resulting primarily

in leg lengthening Mobility of the fragment is enhanced by placing the ipsilateral leg into the figure-of-four position of hip flexion, abduction, and external rotation A triangular wedge of anterior iliac crest is fixed into place at the osteotomy site with two threaded pins directed posteromedially These are subse-quently removed at 6 to 8 weeks in young children and at 3 to 4 months

in older children, who are at a greater risk for graft collapse An iliopsoas tenotomy at the pelvic brim is considered an essential com-ponent of the procedure to both de-crease compression on the femoral head and allow distal fragment mo-bility

In a review of the 15-year data

on 140 patients treated primarily for hip dislocation and subluxation, Salter and Dubos32 reported 93.6%

excellent or good results in patients aged 18 months to 4 years, with no failures In the 4- to 10-year-old age group, however, only 56.7%

had good or excellent results, and the failure rate was 6.6% Initial operative complications included superficial wound infections (inci-dence of 1.5%), femoral head osteo-necrosis (5.7%), loss of osteotomy position prior to the use of two pins (2.8%), redislocation (5.6%), resubluxation (14.3%), and supra-condylar femur fracture (6.4%)

There were no deep infections

Therefore, because less satisfactory results generally occur in older children, triple innominate osteot-omy is preferable for children over age 10

Triple Innominate Osteotomy

The triple osteotomy described

by Steel26in 1965 consists of oste-otomies of the ischium and pubis

in addition to a Salter innominate osteotomy (Fig 5) Tšnnis et al33

have described a modification of the triple osteotomy that is also widely used The triple osteotomy

is generally indicated for older children and adolescents, in whom symphyseal rotation is more limited than in younger children due to skeletal maturity and decreased ligamentous laxity (Fig 6) As is the case with the single innomi-nate osteotomy, concentric hip re-duction is a prerequisite Because

it is a circumacetabular osteotomy, significant mobility of the acetabu-lar fragment is possible In addi-tion, if the ischial osteotomy is directed obliquely from lateral to medial, the acetabular fragment can be displaced medially, moving the hip center to a more physio-logic position and improving gait mechanics

The triple osteotomy requires two incisions Steel26originally ad-vised a horizontal incision made over the ischial tuberosity for the ischial osteotomy and an anterior incision (as in the single innominate procedure) for the pubic and in-nominate osteotomies We now prefer to make the Salter cut only through the anterolateral incision and to make the superior pubic

Fig 4 Salter single innominate osteotomy.

Fig 5 Triple innominate osteotomy.

ramus and ischial cuts through a

single transverse groin incision

Placement of bone graft and

fixa-tion are performed as for the Salter

osteotomy Care must be taken to

avoid excessive external rotation of

the free distal fragment Also,

mus-cle should not intervene in the

pubic and ischial cuts, as

pseudar-throsis can occur Use of a

tempo-rary Schanz screw to guide the

ace-tabular segment allows appropriate

acetabular redirection, avoiding

excessive external rotation

In SteelÕs original series,26 the

results were considered to be

satis-factory in 19 of the 23 hips with

congenital dysplasia followed up

between 2 and 10 years

postopera-tively Five complications were

reported: two cases of

postopera-tive ileus, one ischial wound

infec-tion (Escherichia coli), and two

instances of pressure necrosis of

the skin over the anterior inferior

spine of the displaced acetabular

fragment

In a review of 44 patients (56

hips) an average of 7 years after

triple osteotomy, Faciszewski et

al34reported improvement in both

pain and function in 94% of pa-tients The center-edge angle in-creased by a mean of 33 degrees, and the acetabular angle decreased

by a mean of 15 degrees Two com-plications occurred: one pulmo-nary embolism and one superficial wound infection

Periacetabular Osteotomy

Introduced in 1988 by Ganz et

al,27 the periacetabular osteotomy allows extensive acetabular reori-entation, including medial and lat-eral displacement Osteotomies are performed in the pubis, ilium, and ischium A vertical posterior-column osteotomy connects the posterior extremes of the iliac and ischial osteotomies approximately

1 cm anterior to the sciatic notch (Fig 7) This osteotomy must be done after skeletal maturity, be-cause it crosses the triradiate carti-lage; therefore, it is indicated only for older adolescent and adult pa-tients with dysplastic hips that re-quire improvement of congruency and containment (Fig 8)

Because no complete cut is made into the sciatic notch (the posterior

column is split vertically), the Ganz procedure is very stable, and no postoperative cast is required Im-mediate crutch weight bearing is advised Additional advantages include preservation of the blood supply to the acetabular fragment, use of a single surgical approach, and preservation of the shape of the pelvis, which permits normal vaginal delivery A disadvantage

Fig 6 Images of a female patient with left acetabular dysplasia (same patient as in Fig 1) A, At age 18, AP radiograph of the abducted, internally rotated left hip shows joint congruence B, AP view obtained at age 19, 11 Ú 2 years after left proximal femoral varus osteotomy.

C,Three-dimensional reconstruction of a CT study of the hip obtained at age 21 demonstrates persistent left acetabular dysplasia with

deficient anterolateral coverage D, AP radiograph obtained after triple innominate osteotomy on the left shows improved coverage.

Fig 7 Ganz periacetabular osteotomy.

is that the procedure is difficult to

learn

In 1995, Trousdale et al35reported

the results of use of the Ganz

peri-acetabular osteotomy, with or

without intertrochanteric

osteot-omy, on 42 patients with

dysplas-tic, osteoarthritic hips The

aver-age follow-up interval was 4 years

They found that the Harris hip

score improved from an average

of 62 points preoperatively to 86

points postoperatively (P<0.0001).

The average anterior-edge angle

was 1 degree preoperatively and

27 degrees postoperatively

Com-plications included deep venous

thrombosis in 2 patients, pubic

nonunion in 2, and heterotopic

bone formation in 14 There were

no major neurovascular

complica-tions in this series, although nerve

and/or vessel injury is possible

with this rather complex

oste-otomy

Reshaping (Incomplete)

Osteotomies

The object of reshaping

osteoto-mies is restoration of acetabular

morphology by changing the shape

of the acetabulum They are

pri-marily indicated for the patient

with a capacious or wandering

acetabulum, as is commonly seen

in both childhood DDH and

cere-bral palsy Depending on the os-teotomy, additional lateral and/or posterior coverage can be obtained

They should be used only in the skeletally immature, as the osteot-omy hinges through the triradiate cartilage Because the osteotomy is incomplete, there is inherent stabil-ity after graft placement, and inter-nal fixation is not required

Pemberton Osteotomy

In 1965, Pemberton25 described

an incomplete osteotomy that hinges through the triradiate carti-lage (Fig 9) A Smith-Peterson approach is used to expose the in-ner and outer tables of the ilium

The outer ilium is osteotomized beginning immediately superior to the anterior inferior iliac spine

The osteotomy extends posteriorly 0.25 inch above and parallel to the joint capsule and is carried to the ilioischial limb of the triradiate car-tilage The inner ilium is osteoto-mized separately to match the outer cut (if anterior coverage is primarily desired); alternatively, the posterior limb may be shifted anteriorly to provide additional lat-eral coverage Care must be taken

to remain halfway between the anterior edge of the sciatic notch and the posterior rim of the acetab-ulum

The osteotomy is opened enough

to create an acetabular angle of

approximately 0 degrees A groove

is created to hold the graft in posi-tion, and a triangular wedge of bone from the anterior ilium is placed and impacted No internal fixation is required A spica cast is used for 8 weeks This osteotomy is appropriate for patients between the age of 18 months and skeletal maturity (Fig 10)

In PembertonÕs original series of

91 patients (115 hips), all 46 chil-dren less than 4 years of age had a good result.25 There were 20 good and 4 fair results in children aged 4

to 7 years, and 12 good, 6 fair, and

3 poor results in children between the ages of 7 and 12 years

Fig 8 Images of a 15-year-old girl with left acetabular dysplasia A, Preoperative AP radiograph of the pelvis B, Three-dimensional CT reconstruction shows significant uncovering of the left hip C, AP radiograph obtained after a Ganz periacetabular osteotomy.

Fig 9 Pemberton osteotomy.

plications included 5

redisloca-tions, 12 cases of osteonecrosis (all

eventually healed), and 2 sciatic

nerve palsies (in cases of high

dis-location)

Faciszewski et al36 reported the

results in 52 hips with acetabular

dysplasia treated with the

Pember-ton osteotomy The average age of

the 42 patients was 4 years at the

time of surgery The mean

follow-up interval was 10 years At the

time of follow-up, 42 hips (81%)

were radiographically normal No

patient had pain, three patients had

decreased range of motion, and one

patient had a positive

Trendelen-burg test There were no

complica-tions

Dega Osteotomy

The Dega osteotomy is an

tabuloplasty that also changes

ace-tabular configuration and shape

It provides increased

posterolater-al coverage by means of an osteot-omy of the lateral cortex of the ilium only, hinging through the open triradiate cartilage.37 The primary indication for this osteot-omy is the presence of a capacious acetabulum with posterolateral deficiency, as is often found in children with cerebral palsy

Some authors also use it for persis-tent acetabular dysplasia in DDH

The technique has been well de-scribed by Mubarak et al.37

Salvage/Augmentation Procedures

A salvage osteotomy may be indi-cated when a congruent reduction between the femoral head and the

acetabulum cannot be obtained Such an osteotomy may also be appropriate for an adolescent or adult with a painful subluxated hip

or for a patient with prior surgical failures Selection of one of the var-ious salvage/augmentation proce-dures presupposes that the remain-ing hyaline cartilage is inadequate

or cannot be redirected to provide coverage of the femoral head These procedures act to increase the weight-bearing surface and rely on capsular metaplasia to provide an articulating surface Commonly, an associated valgus or varus

osteoto-my will help to realign the joint and decompress the joint

Chiari Osteotomy

The primary indication for use of the Chiari osteotomy is a painful, subluxated hip without the

Fig 10 Images of a girl with bilateral acetabular dysplasia A, At 3 years of age, AP radiograph of the pelvis showed bilateral dysplasia.

B,At 7 1 Ú 2years of age, three-dimensional reconstruction of a CT study of the pelvis showed persistent dysplasia C, Radiograph of the right hip obtained during a Pemberton osteotomy D, Anteroposterior radiograph of the pelvis obtained 2 months after bilateral

Pemberton osteotomies shows graft incorporation and improved coverage.