1. Imaging, 14 (2002), 179–187 E 2002 The British Institute of Radiology
Imaging of children’s hips
1
D WILSON, MBBS, BSc, FRCP, FRCR and 2G ALLEN, BM DCH, MRCGP, MRCP, FRCR
1
Nuffield Orthopaedic Centre, Oxford and 2Royal Orthopaedic Hospital, Birmingham, UK
Children may present with hip disease in a
variety of ways. In the newborn it may be detected Summary
by routine clinical examination. In the older child
pain, stiffness and limping are the primary
symptoms. In the toddler ‘‘going of their feet’’
N Ultrasound is an important tool in thedysplasia
and management of developmental
detection
may be the presenting event. of the hip.
Most children who complain of pain in the hip
have genuine pathology. It is an unusual location N Universal screening for developmental
for a child to make up or exaggerate complaints. dysplasia of the hip by ultrasound may be wise
Imaging has a pivotal role in the management of but there is currently insufficient evidence to
these patients who may have disease that requires clearly recommend this a national policy.
urgent medical or surgical treatment.
In most cases a child or infant complaining of a
N A painful hip in childhood is a clinical
emergency.
painful hip should be examined and investigated
as a matter or urgency. Hospitals should provide N Ultrasound is the definitive method for
on-call imaging and general practitioners should detecting joint effusion.
be fully aware of local facilities and management
protocols.
N Ultrasound cannot determine whether a joint
effusion is due to infection, haemorrhage or
transudate.
Developmental dysplasia
N Imaging has a role in determining the cause of
Between 1 and 3 newborns per 1000 live births snapping hips.
will be diagnosed as suffering from developmental
dysplasia of the hip (DDH), formerly known as
congenital dislocation of the hip, with a female vehement advocates. In reality, local outcome
preponderance of 9:1. This hides the much larger measures must be the standard by which these
incidence of premature osteoarthritis that devel- techniques are judged. The best method applied
ops in young adults who have a shallow and badly or administered ineffectively will be of less
mechanically disadvantaged hip that is not bad use than a less technically demanding method that
enough to have presented in infancy. Many who is used rigorously with top quality clerical and
undergo hip replacement in their middle years are management support.
undiagnosed cases of DDH. The true incidence of
DDH is therefore much higher, although there are
no clear figures in the literature (Figures 1 and 2).
There is good evidence that early treatment of
DDH with splint therapy improves prognosis [1].
This is only effective in the first 6 months of
life when remodelling is very active. Therefore if
diagnosis is made early enough, overall popula-
tion morbidity may be reduced. It was this rationale
that led to the now universal clinical screening
protocols using Barlow and Ortolani manoeuvres
to detect subtle subluxation and instability of the
hip. Unfortunately clinical examination, even in
the best of hands, will overlook a substantial
proportion of cases that would benefit from early
treatment. Ultrasound introduces an additional
Figure 1. Plain radiograph of a 28-year-old who has
method of screening that considerably improves early osteoarthritis secondary to developmental dys-
detection [2–7]. A number of methods have been plasia that was asymptomatic as a child and young
developed and each has strong and sometimes adult.
Imaging, Volume 14 (2002) Number 3 179
2. D Wilson and G Allen
Figure 2. Plain radiograph of a pseudarthrosis result-
ing from unrecognized dislocation of the hip.
Most techniques stem from that developed by
Professor Graf, an Austrian orthopaedic surgeon.
Figure 4. Ultrasound of a shallow acetabulum that
Graf uses coronal plane ultrasound to produce a would be treated by a splint or harness.
standard section equivalent in orientation to a
frontal radiograph of the hip. Lines drawn on the More contentious is deciding upon the popula-
image are used to measure the angular depth of tion to be screened. Infants with family history of
the acetabulum and the cover of the femoral head. hip dysplasia, those born by breech delivery and
Strict adherence to the technique is essential as those with other congenital anomalies are at much
small variations in measurement will alter classi- higher risk of developing DDH. Screening of
fication and affect management protocols. Others those at high risk in addition to those who are
have introduced less demanding methods of mea- suspected as being abnormal on routine clinical
surement, although still requiring discipline in examination is the most common practice in the
image acquisition (Figures 3–5). It has been UK. Others argue that this policy will fail to
argued that a static image alone is less sensitive provide the most accurate and sensitive detection
than a morphological measure plus a dynamic of all who might benefit from early treatment and
stress test, and there is evidence that this improves suggest universal screening [11]. In Austria and
detection [8]. In most practices a combination of Germany, child benefit entitlement is linked to
static and dynamic imaging is employed [9, 10]. attending for screening. One counter to this
Figure 3. Ultrasound of a borderline depth acetabu- Figure 5. Ultrasound of a dislocated hip that required
lum with measurement using the Morin method. surgical reduction.
180 Imaging, Volume 14 (2002) Number 3
3. Imaging of children’s hips
argument is that required resources are not cost to immediate pain relief [25, 26]. There are no
effective, although this is a difficult line to take in organisms present on Gram stain and culture will
what is an emotionally charged topic. Indeed be negative.
there is evidence that the overall saving in Pain may be treated with analgesia, however,
resources is conquerable in all screening strategies this is not very effective. Some advocate skin
[12, 13]. More telling is the point that standards of traction and bed rest but this requires hospital
detection are likely to drop in any universal admission. A diagnostic aspirate of the joint is a
screening project and that there is currently no more effective method of analgesia as there is
evidence that overall population outcome is better instant pain relief and restoration of function.
in those centres where it is practiced. Further Local anaesthetic jelly and ultrasound guidance
epidemiological research is required before firm allow a safe and rapid joint puncture and prevent
recommendations can be made, and current hospital admission in many cases.
advice in the UK is to perform ultrasound
screening in infants in the high risk category only.
Septic arthritis
In complex congenital hip disorders a combina-
tion of ultrasound, plain radiography and MRI Pyogenic organisms may infect the hip via a
are indicated, especially for planning surgery [14, blood borne route. Staphylococcus aureus and
15]. For example, in deficiency of the proximal haemophylus influenzae are the most common
femur either ultrasound or MRI may be used to organisms. If infection is untreated the joint will
detect whether there is a cartilage fragment in the be rapidly destroyed. Consequent septicaemia
gap and to determine the integrity of the hip joint may be life threatening. The only effective therapy
[16]. is a combination of arthotomy with joint lavage
Following surgery or splint therapy, MRI is and intravenous antibiotics. Clinical presentation
useful to assess the degree and efficacy of reduc- is often indistinguishable from transient synovitis.
tion [17]. In managing pelvic and femoral Fever and serological signs of inflammation are
osteotomies the information from cross-sectional often absent. The degree of irritability does not
imaging is important [18, 19]. predict diagnosis and ultrasound appearances of
septic arthritis are no different from transient
synovitis [27]. The only effective means of diag-
Irritable hip
nosis is aspiration, Gram stain and culture.
Children between the ages of 3 years and 12 Fortunately the condition is rare and those who
years commonly suffer from acute episodes of hip rely on ineffective methods of diagnosis will only
pain. The vast majority are suffering from rarely cause permanent damage.
transient synovitis, which is a benign and self-
limiting condition. Unfortunately, a small but
Perthes disease
important minority have a more serious com-
plaint such as septic arthritis and need urgent Osteochondrosis of the hip, Legg–Calve– ´
surgical management to minimize long-term Perthes disease, is an uncommon disease of
disability [20]. The challenges are detecting and unknown cause. The most convincing theory is
treating this small subset whilst treating the pain that it is the result of trauma in an immature
and discomfort of the majority in a timely and joint. Again, presentation is with pain and
safe manner. limitation of movement. The child may be older
(7–14 years) and there is sometimes a history of
previous episodes of pain. Plain radiography is
Transient synovitis
diagnostic showing fragmentation, roughening,
The cause of transient synovitis is not known. flattening and distortion of the femoral capital
There are postulates that it is traumatic or epiphysis (Figures 6–8). In the early phase the
infective in origin, but neither is proven. The plain radiograph shows widening of the hip joint
condition presents with a short history of pain owing to cartilage overgrowth. Long-term dis-
and limping, which typically resolves within 3–4 ability may result owing to alteration in shape and
days. Although MRI, CT and ultrasound will all mechanical stress. Treatment is based around
detect effusions [21], ultrasound is the established surgery designed to confine the femoral head
method of choice as it is readily available, easy to within the joint, and often includes pelvic and
perform and extremely accurate [22–24]. Ultrasound femoral osteotomies. Ultrasound examination in
examination shows a joint effusion with capsular the early stages of the condition will show joint
distension and a varied amount of synovial thicken- effusion [5, 28–30] and the fragmented epiphysis
ing. A difference of 2 mm or more between the may be visible, but this method should not be
hips is significant. Joint aspirate will be clear and relied upon. For older children with an irritable
straw coloured and depressurizing the joint leads hip a plain radiograph is mandatory to exclude
Imaging, Volume 14 (2002) Number 3 181
4. D Wilson and G Allen
predicting osteonecrosis by assessing vascular
supply to the epiphysis [38]. MRI also has
important roles in surgical planning and in
detecting occult disease in the opposite hip. It is
also valuable in assessing the late sequelae of
Perthes disease [39, 40].
Slipped epiphysis
Older children (8–14 years) may suffer from
slipped upper femoral capital epiphysis (SUFE).
This typically occurs in boys heavier than average
and is thought to be the result of mechanical
stress on the immature growth plate. Presentation
is also with pain and limping of short duration.
Figure 6. A frog lateral view of a child with sus-
pected slipped upper femoral capital epiphysis;
The only effective treatment is surgical fixation,
appearances are normal. most commonly achieved by inserting pins into
the epiphyses via the femoral neck. If treatment is
delayed the slip will worsen with considerably
increased risk of osteonecrosis in the displaced
epiphysis and severe long-term consequences [41,
42]. Detection and treatment are therefore urgent.
Whilst ultrasound will show an effusion in 75% of
cases, and may show the step in the contour of the
femoral head [43–45], it is not as safe and
effective as plain radiograph examination using a
frog lateral projection. SUFE represents a Salter–
Harris 1 type lesion of the proximal femoral
epiphysis. The slip most often occurs in a postero-
medial direction and may be difficult to see on
anteroposterior (AP) radiography [46]. A frog
lateral is mandatory. It is reasonable to omit the
conventional AP film to reduce radiation dose to
Figure 7. The same child as in Figure 6, 1 month the patient. MRI is useful to asses direction and
later, showing contour changes and sclerosis of severity of the slip, especially in planning surgery
Perthes disease.
[47]. It is particularly useful in detecting occult or
subtle slip in the opposite asymptomatic hip,
which may occur in up to 60% of cases. This
examination should be performed prior to surgery
on the affected hip as prophylactic pinning under
the same anaesthetic is possible [48] (Figures 9–11).
Investigation of irritable hip
From the above it should be apparent that a
child with an irritable hip should be seen as an
emergency. The clinician should take a history
and confirm the hip as the origin of pain by
clinical examination. Ultrasound examination
Figure 8. Established Perthes disease with frag-
should be arranged as an emergency [49, 50]. If
mentation and flattening of the right femoral capital there is no joint effusion plain radiography should
epiphysis. be undertaken [44, 45]. If this is normal then other
causes of pain should be considered, e.g. retro-
slipped epiphysis and Perthes disease [31]. Children caecal appendicitis, muscle strain and referred
with recurrent irritable hip should be examined by back pain.
MRI as this technique may detect the condition If ultrasound examination shows fluid, a
when plain radiograph changes have not yet therapeutic and diagnostic aspiration should be
occurred [32–37] (Figure 3). Gadolinium (Gd) performed. Fluid should be sent for urgent Gram
DTPA enhancement may prove to be useful in stain and culture (Figures 12 and 13).
182 Imaging, Volume 14 (2002) Number 3
5. Imaging of children’s hips
Figure 9. Early slipped epiphysis missed as the subtle
changes were not noticed and a lateral view was not
performed.
Figure 11. MRI of advanced slipped epiphysis.
Figure 10. 6 weeks after the image in Figure 9, the
slip was recognized. There is now significant change,
the epiphysis being rendered avascular with a poor
outcome. Figure 12. Ultrasound of a normal hip without an
effusion.
In older children (over 8 years) plain radiog-
raphy in a frog lateral should be performed. Presentation varies greatly from an acutely
In complex or recurrent cases, MRI should be painful region, immobility and systemic toxicity
considered as an additional investigation [51, 52]. through to a completely occult disease with minimal
If MRI is not available there is a role for isotope local symptoms and just s general sense of ill
bone scintigraphy to detect occult bone lesions health.
[53]. Acute infection is typified by bone oedema and
subperiosteal reaction. The latter may be seen on
plain radiography but both are readily apparent
on MRI. The oedema extends beyond the area
Osteomyelitis that is histologically identifiable as active inflam-
Bone infection may be primary due to blood matory response but it is difficult, if not impossible,
borne organisms or secondary due to implantation, to distinguish this margin using imaging. It has
surgery or other forms of trauma. Occasionally been suggested that areas of true infection would
infection spreads to bone from septic arthritis. enhance with intravenous Gd DTPA injection on
Imaging, Volume 14 (2002) Number 3 183
6. D Wilson and G Allen
Juvenile arthritis
Juvenile arthropathy may present in the hip,
although other joints such as the wrist or knees
are more common presenting locations. It should
be considered as a possible diagnosis in recurrent
or complicated cases where diagnosis of transient
synovitis is in doubt. Synovial reaction will be
visible on ultrasound as thickening and irregular-
ity of the capsule. MRI may be more difficult to
interpret as the high signal from fluid in the joint
seen on T2 weighted or short tau inversion recovery
(STIR) images will be the same signal as exhibited
by thickened and oedematous synovium [56]
(Figure 14). Intravenous Gd DTPA enhancement
would resolve this issue but ultrasound is cheaper,
faster and more acceptable to the patient. Ultrasound
is the imaging method of choice for detecting
Figure 13. Ultrasound of a hip with a substantial effusion and pannus [57] and it has a very useful
effusion. Aspirate was sterile. The appearances of role in follow-up studies [58].
septic arthritis may be identical.
Trauma
MRI, however, this is not a reliable test and in Fractures and dislocations around the hip
practice it is rare for contrast enhancement to are rare in children [59, 60]. They tend to be
assist in management. Subperiosteal reaction may associated with high energy injuries. Fractures
be detected using ultrasound. A positive finding should be apparent on plain radiography but
on ultrasound is very specific but a negative study minimally displaced fractures and stress lesions
does not exclude acute osteomyelitis. may not. MRI is the definitive test and will show
Chronic infection and acute infection after all fractures as low signal lines on T1 weighted
antibiotic therapy are best studied by a combina- images surrounded by high signal material on T2
tion of plain radiographs to detect bony destruc- weighted or STIR sequences. MRI also has a role
tion and sclerosis, with MRI to show the extent of in complex fractures of the acetabulum when CT is
diseased bone, abscess within and outside bone not conclusive [61]. Non-accidental injury should
and the extent and nature of soft tissue involve-
ment [54]. Ultrasound is useful in excluding or
defining soft tissue abscesses [55]. CT is sometimes
useful in defining the shape and extent of sclerotic
sequestered fragments. The response to drug
treatment and planning of surgical debridement
depends very much on follow up studies. Serial
MRI studies are invaluable in deciding timing and
extent of surgery. Again, contrast enhancement
rarely alters clinical decisions.
Tumours may mimic infection and vice versa.
In most cases biopsy is indicated and MRI will be
important in deciding where to biopsy and via
which route. Infection in bone is notorious for the
difficulty in identifying the organisms. Even in
proven and definite osteomyelitis only 30% of
biopsy specimens will grow organisms. For this
reason it is important to send biopsy material for
histological examination as this is more often the
means by which infection is established. Image
guided needle biopsy is valuable. However, in
children an open biopsy under general anaesthesia
is not only kinder but may also treat symptoms
as the marrow oedema may be depressurized, Figure 14. T2 weighted coronal MRI of a joint effu-
relieving some of the pain. sion and synovitis in juvenile arthritis.
184 Imaging, Volume 14 (2002) Number 3
7. Imaging of children’s hips
always be considered in younger age groups. 5. Terjesen T. Ultrasonography in the primary evalua-
Ultrasound can also pick up fractures in the tion of patients with Perthes disease. J Pediatr
Orthop 1993;13:437–43.
younger patient. 6. Terjesen T. Ultrasound as the primary imaging
Acute chondral injuries due to sheering forces method in the diagnosis of hip dysplasia in children
may cause an acute arthropathy. If there is a aged ,2 years. J Pediatr Orthop B 1996;5:123–8.
resulting defect in the articular surface, symptoms 7. Poul J, Bajerova J, et al. Selective treatment
may persist and fail to resolve. Conventional MRI program for developmental dysplasia of the hip in
an epidemiologic prospective study. J Pediatr
may show the lesion especially on T2 weighted fast
Orthop B 1998;7:135–7.
spin echo images, although it may be necessary to 8. Finnbogason T, Jorulf H. Dynamic ultrasono-
perform MR arthrography to be sure. CT arthrog- graphy of the infant hip with suspected instability.
raphy is also effective but is less suitable in A new technique. Acta Radiol 1987;38:206–9.
children as the radiation burden is large. 9. Joseph KN, Meyer S. Discrepancies in ultrasono-
Muscle strains and tears may mimic irritable graphy of the infant hip. J Pediatr Orthop B
1996;5:273–8.
hip. They may be invisible on all imaging but 10. Poul J, Garvie D, et al. Ultrasound examination of
significant tears will be well seen on ultrasound as neonate’s hip joints. J Pediatr Orthop B 1998;7:59–
defect in the myofibrillar structure, oedema and 61.
scar tissue. Dynamic stress ultrasound will show 11. Marks D, Clegg J, et al. Routine ultrasound
muscle tears by the retraction of muscle and screening neonatal hip instability. Can it abolish
late-presenting congenital dislocation of the hip.
bulging of the margins of the tear. In the acute J Bone Joint Surg 1994;76:534–8.
phase, MRI of the affected area may be the most 12. Davids JR, Benson LJ, et al. Ultrasonography and
sensitive test. developmental dysplasia of the hip: a cost-benefit
Growth plate injuries are a particular problem analysis of three delivery systems. J Pediatr Orthop
in children. Their management depends on the 1995;15:325–9.
13. Clegg J, Bache CE, et al. Financial justification for
extent and the skeletal age of the child. MRI is
routine ultrasound screening of the neonatal hip. J
the best method of studying the nature of the Bone Joint Surg Br 1999;81:852–7.
injury [62]. 14. Exner GU, Frey E. [Hip dysplasia in infancy.
Proton spin tomography and computerized tomo-
graphy]. Orthopade 1997;26:59–66. (In German.)
15. Tegnander A, Terjesen T. Reliability of ultrasono-
Snapping hip graphy in the follow-up of hip dysplasia in children
above 2 years of age. Acta Radiol 1999;40:619–24.
A variety of clicks and snaps may occur around 16. Court C, Carlioz H. Radiological study of severe
the hip. These are most common in teenage girls. proximal femoral focal deficiency. J Pediatr Orthop
They include iliopsoas snaps, iliotibial tract 1997;17:520–4.
snapping, greater trochanteric bursitis and glenoid 17. Kashiwagi N, Suzuki S, et al. Prediction of
labral injuries. Static ultrasound will demonstrate reduction in developmental dysplasia of the hip
by magnetic resonance imaging. J Pediatr Orthop
inflamed bursae and thickening whilst dynamic 1996;16:254–8.
ultrasound is much more useful as it will show the 18. Lin CJ, Romanus B, et al. Three-dimensional char-
clicking or snapping tendon [63–65]. Local anaes- acteristics of cartilaginous and bony components
thetic blocks of the snapping tendon guided by of dysplastic hips in children: three-dimensional
imaging are useful in confirming diagnosis when computed tomography quantitative analysis. J Pediatr
Orthop 1997;17:152–7.
more invasive forms of treatment are being 19. MacDonald J, Barrow S, et al. Imaging strategies in
considered. Labral tears will only be visible on the first 12 months after reduction of developmental
MRI or CT arthrography [66–69]. They are more dislocation of the hip. J Pediatr Orthop B
common anteriorly than superiorly and imaging 1995;4:95–9.
should include axial sections following the joint 20. Champoux A, Bockers T, et al. Septic arthritis
versus transient synovitis of the hip: the value of
injection.
screening laboratory tests. Ann Emerg Med
1992;21:1418–22.
21. Ranner G, Ebner F, et al. Magnetic resonance
imaging in children with acute hip pain. Pediatr
References Radiol 1989;20:67–71.
1. Teo EL. Clinics in diagnostic imaging (69). Bilateral 22. Wilson D, Green D, et al. Arthrosonography of the
developmental dysplasia of the hip. Singapore Med painful hip. Clin Radiol 1984;35:17–9.
J 2002;43:49–52. 23. Egund N, Wingstrand H, et al. Computed tomo-
2. Berman L, Klenerman L. Ultrasound screening for graphy and ultrasonography for diagnosis of hip
hip abnormalities. Preliminary findings in 1001 joint effusion in children. Acta Orthop Scand
neonates. BMJ 1986;293:719–22. 1986;57:211–5.
3. Novick G. Sonography in paediatric hip disorders. 24. Harcke H, Grissom L. Pediatric hip sonography.
Radiol Clin North Am 1988;26:29–53. Diagnosis and differential diagnosis. Radiol Clin
4. Castelein R, Sauter A, et al. Natural history of North Am 1999;37:787–96.
ultrasound hip abnormalities in clinically normal 25. Berman L, Fink A, et al. Technical note: identifying
newborns. J Pediatr Orthop 1992;12:423–7. and aspirating hip effusions. BJR 1995;68:306–10.
Imaging, Volume 14 (2002) Number 3 185
8. D Wilson and G Allen
26. Fink A, Berman L, et al. The irritable hip: 44. Castriota-Scanderbeg A, Orsi E, et al.
immediate ultrasound guided aspiration and pre- [Ultrasonography in the diagnosis and follow-up
vention of hospital admission. Arch Dis Child of hip pain in children]. Radiol Med (Torino)
1995;72:110–3. 1993;86:808–14. (In Italian.)
27. Zawin JK, Hoffer FA, et al. Joint effusion in 45. Castriota-Scanderbeg A, Orsi E. Slipped capital
children with an irritable hip: US diagnosis and femoral epiphysis: ultrasonographic findings.
aspiration. Radiology 1993;187:459–63. Skeletal Radiol 1993;22:191–3.
28. Wirth T, LeQuesne G, et al. Ultrasonography in 46. Shanker VS, Hashemi-Nejad A, et al. Slipped
Legg-Calve-Perthes disease. Pediatr Radiol 1992; capital femoral epiphysis: is the displacement
22:498–504. always posterior? J Pediatr Orthop B 2000;9:119–
29. Bosch R, Niedermeier C, et al. [Value of ultrasound 21.
in differential diagnosis of pediatric hip joint 47. Umans H, Liebling M, et al. Slipped capital femoral
effusion (Perthes disease, C. fugax, epiphysiolysis epiphysis: aphyseal lesion diagnosed by MRI, with
coapitis femoris]. Z Orthop Ihre Grenzgeb 1998; radiographic and CT correlation. Skeletal Radiol
136:412–9. 1998;27:139–44.
30. Eggl H, Drekonja T, et al. Ultrasonography in the 48. Futami T, Suzuki S, et al. Sequential magnetic
diagnosis of transient synovitis of the hip and Legg- resonance imaging in slipped capital femoral
Calve-Perthes disease. J Pediatr Orthop 1999;8:177– epiphysis: assessment of preslip in the contralateral
80. hip. J Pediatr Orthop B 2001;10:298–303.
31. Robben SG, Meradji M, et al. US of the painful hip 49. Konermann W, Gruber G, et al. [Standardized
in childhood: diagnostic value of cartilage thicken- sonographic examination of the hip joint].
ing and muscle atrophy in the detection of Perthes Ultraschall Med 2000;21:137–41. (In German.)
disease. Radiology 1998;208:35–42. 50. Marchal GJ, Van Holsbeeck MT, et al. Transient
32. Toby EB, Koman LA, et al. Magnetic resonance synovitis of the hip in children: role of US.
imaging of pediatric hip disease. J Pediatr Orthop Radiology 1987;162:825–8.
1985;5:665–71. 51. de Pellegrin M, Fracassetti D, et al. [Coxitis fugax.
33. de Sanctis N, Rega AN, et al. Prognostic evaluation The role of diagnostic imaging]. Orthopade
of Legg-Calve-Perthes disease by MRI. Part I: the 1997;26:858–67. (In German.)
role of physeal involvement. J Pediatr Orthop 52. Thomas S, Tytherleigh-Strong G, et al. Adductor
2000;20:455–62. myositis as a cause of childhood hip pain. J Pediatr
34. Hosokawa M, Kim WC, et al. Preliminary report Orthop B 2002;11:117–20.
on usefulness of magnetic resonance imaging for 53. Alexander JE, Seibert JJ, et al. A protocol of plain
outcome prediction in early-stage Legg-Calve- radiographs, hip ultrasound, and triple phase bone
Perthes disease. J Pediatr Orthop B 1999;8:161–4. scans in the evaluation of the painful pediatric hip.
35. Minio Paluello GB, De Pellegrin M, et al. Clin Pediatr (Phila) 1988;27:175–81.
[Persistent coxalgia in the child. The value of magnetic 54. Kearney SE, Carty H. Pelvic musculoskeletal
resonance]. Radiol Med (Torino) 1997;89:402–8.(In infection in infants—diagnostic difficulties and
Italian.) radiological features. Clin Radiol 1997;52:782–6.
36. Ranner G. [Osteochondrosis deformans coxae 55. Tran-Minh VA, Pracros JP, et al. Sonography of
juvenilis (Legg-Calve-Perthes disease) in the MR the hip and soft tissues of the thigh in children.
tomogram: diagnosis and follow-up assessment Radiol Med (Torino) 1993;85(5 Suppl. 1):247–51.
correlated with x-rays and skeletal scintigraphy]. 56. Lamer S, Sebag GH. MRI and ultrasound in
Rofo Fortschr Geb Rontgenstr Neuen Bildgeb children with juvenile chronic arthritis. Eur J Radiol
Verfahr 1990;153:124–30. (In German.) 2000;33:85–93.
37. Schittich I, Gradinger R, et al. [Legg-Calve-Perthes 57. Eich GF, Halle F, et al. Juvenile chronic arthritis:
disease in the MRI: possibilities and limits]. Z Orthop imaging of the knees and hips before and after
Ihre Grenzgeb 1990;128:404–10. (In German.) intraarticular steroid injection. Pediatr Radiol
38. Sebag G, Ducou Le Pointe H, et al. Dynamic 1994;24:558–63.
gadolinium-enhanced subtraction MR imaging—a 58. Friedman S, Gruber MA. Ultrasonography of the
simple technique for the early diagnosis of Legg- hip in the evaluation of children with seronegative
Calve-Perthes disease: preliminary results. Pediatr juvenile rheumatoid arthritis. J Rheumatol
Radiol 1997;27:216–20. 2002;29:629–32.
39. Lahdes-Vasama TT, Lamminen AE, et al. MRI in 59. Gennari JM, Merrot T, et al. X-ray transparency
late sequelae of Perthes’ disease: imaging findings interpositions after reduction of traumatic disloca-
and symptomatology in ten hips. Pediatr Radiol tions of the hip in children. Eur J Pediatr Surg
1996;26:640–5. 1996;6:288–93.
40. Mastantuono M, Milella PP, et al. [Role of 60. Macnicol MF. The Scottish incidence of traumatic
magnetic resonance in the evaluation of the normal dislocation of the hip in childhood. J Pediatr
and osteochondrosis hip in early and late child- Orthop B 2000;9:122–4.
hood]. Radiol Med (Torino) 1997;94:571–8. (In 61. Rubel IF, Kloen P, et al. MRI assessment of the
Italian.) posterior acetabular wall fracture in traumatic
41. Cowell H. The significance of early diagnosis dislocation of the hip in children. Pediatr Radiol
and treatment of slipping of the capital femoral 2002;32:435–9.
epiphyses. Clin Orthop 1966;48:89–94. 62. Futami T, Foster BK, et al. Magnetic resonance
42. Boles C, el-Khoury G. Slipped capital femoral imaging of growth plate injuries: the efficacy and
epiphysis. Radiographics 1997;17:809–23. indications for surgical procedures. Arch Orthop
43. Kallio P, LeQuesne G, et al. Ultrasonography in Trauma Surg 2000;120:390–6.
slipped capital femoral epiphysis. J Bone Joint Surg 63. Pelsser V, Cardinal E, et al. Extraarticular snapping
1991;73:884–9. hip: sonographic findings. AJR 2001;176:67–73.
186 Imaging, Volume 14 (2002) Number 3
9. Imaging of children’s hips
64. Wunderbaldinger P, Bremer C, et al. Efficient 67. Grainger AJ, Elliott JM, et al. Direct MR
radiological assessment of the internal snapping arthrography: a review of current use. Clin Radiol
hip syndrome. Eur Radiol 2001;11:1743–7. 2000;55:163–76.
65. Choi YS, Lee SM, et al. Dynamic sonography of 68. Erb RE. Current concepts in imaging the adult hip.
external snapping hip syndrome. J Ultrasound Med Clin Sport Med 2001;20:661–96.
2002;21:753–8. 69. Petersilge CA. MR arthrography for evaluation of
66. Ghebontni L, Roger B, et al. MR arthrography the acetabular labrum. Skeletal Radiol 2001;30:423–
of the hip: normal intra-articular structures and 30.
common disorders. Eur Radiol 2000;10:83–8.
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