Diagnostic ultrasound ( PDFDrive )

CHAPTER 55 The Pediatric Hip and Other Musculoskeletal Ultrasound Applications 1929
A
B
C
FIG. 55.4 Hip Anterior Views—Anterior Axial With Flexion and Abduction. (A) Scan area (dotted lines) on a computed tomography (CT)
scan. a, Acetabulum; A, anterior; L, lateral; m, metaphysis. (B) Normal hip sonogram shows sonolucent femoral head (H) bordered by metaphysis
(m) laterally and acetabulum (a) medially. (C) Dislocated hip sonogram shows posterior displacement of femoral head (H) and metaphysis (m).
be noted. Deformity and increased echogenicity of the cartilage
are indications of more severe acetabular dysplasia.
Evaluation During Treatment
he usefulness of sonography in the follow-up of infants with
DDH, whether for observation of resolving abnormality or in
conjunction with a deined treatment regimen, is widely accepted.
Currently, sonography is routinely used to follow borderline
cases, particularly in very young infants, before a commitment
is made to a treatment regimen. When treatment is indicated,
ultrasound is typically used to monitor hip position during
treatment. Dynamic splints, such as the Pavlik harness, hold the
hip in a lexed abducted position. hese restraints and similar
devices are popular, and ultrasound has been tested as a way of
monitoring hip position for infants in splint devices. 34,39,40 he
sonographic examination in these patients is limited to the
transverse/lexion and coronal/lexion views. he stress portion
of the examination should not be performed unless requested.
Typically, stress is not used until the conclusion of treatment,
when weaning from the harness is instituted.
One of the problems with follow-up sonography has been its
reliability in morphologic assessment of the bony acetabulum.
Reports of discrepancies between the sonographic appearance
of the bony acetabulum and the radiographic appearance
indicate inexact correlation. 34 his may result from observer
variation and the nature of the ultrasound measurements. he
American Academy of Orthopaedic Surgeons (AAOS) guideline
states that at 4 to 6 months of age it is appropriate to shit to
the radiograph when following a patient. 41 We have chosen to
include the pelvic radiograph as a baseline toward the end of the
treatment protocol. he older the infant, the more we tend to
consider radiography, particularly when the ossiication centers
are large. Ater successful treatment, continued monitoring of
acetabular development by periodic radiographs is prudent.
Residual acetabular dysplasia is reported in a small number
of patients. 42