Riyadh Military hospital
What is DDH
• The natural history of DDH dictates that
this is not necessarily a simple task.
• DDH is composed of two elements:
• (1) instability and
• (2) abnormal morphology.
• The technique for performing an infant hip
sonogram may vary depending upon one's belief
as to pathophysiology.
• Initial focus of hip sonography by Graf was on
acetabular morphology, using a single static
• Harcke et al, on the other hand, emphasized
assessment of instability in addition to
morphology and advocated a dynamic
• The current recommendation for
sonographic examination of the infant hip
incorporates assessment of both instability
and morphology so the pathophysiology
issue is resolved with respect to
performance of the sonographic
TABLE 1 -- HIP SONOGRAPHY FOR DEVELOPMENTAL DYSPLASIA OF THE HIP
Stability (if stressed)
Used with Pavlik harness
Stress required (except during treatment)
Used with Pavlik harness
Femoral head position
Data from Harcke HT, Grissom LE: Performing dynamic sonography of the infant hip. AJR Am J Roentgenol 155:837-844, 1990;
• This system is based upon the
appearance of the acetabulum in a
coronal neutral position and describes
measurement of acetabular slope (alpha
angle) and position of the acetabular
labrum (beta angle).
• It is a well-recognized feature of DDH that
the condition changes with time.
• It is greater at birth and decrease
spontaneously in the first few months of
life without treatment.
• Of particular relevance is the distinction of
normal and abnormal in the first few
weeks of life. It is recognized that a large
number of newborns have a mild instability
that has been described as physiologic
laxity. In association with this is mild
acetabular dysplasia consisting of a
slightly increased angulation of the bony
acetabulum as determined by Graf alpha
angles (type 2A).
How to make good
• The proper coronal view, whether the femur is in
neutral or in flexion, contains three elements .
• (1) The echoes from the bony ilium should be in
a straight line parallel to the surface of the
• (2) The transition from the os ilium to the
triradiate cartilage must be seen definitively.
• (3) Finally, the echogenic tip of the cartilage
labrum needs to be present in the same plane
that contains the other two elements.
Graf classification of infant hips based on the depth and shape
of the acetabulum as seen on coronal ultrasonograms.
Type I: normal; characterized by a well-formed acetabular cup
with the femoral head beneath the acetabular roof.
Type II: immature in infants less than three months of age and
mildly dysplastic in infants older than three months;
characterized by a shallow acetabulum with a rounded rim.
Type III: subluxated; characterized by a very shallow
acetabulum with some displacement of the femoral head.
Type IV: dislocated; characterized by a flat acetabular cup and
loss of contact with the femoral head.
II- Stability assesment
• The assessment of instability incorporates
dynamic technique in two views that
include application of stress.
• Both views are performed with the hip
flexed: the transducer orientation is
coronal for one view and axial for the
Relax your patient
• Assessing the hip when the infant is not
relaxed masks the presence of instability.
• To ensure a cooperative infant, it is
recommended that a sonogram be
performed in a quiet, semidarkened
environment with a parent present and
visible to the child.
• Bottle feeding the infant during the
examination is helpful.
• Examination by ultrasound is modeled
after the clinical examination and is based
upon the provocative test for dislocation of
an unstable hip (Barlow test) or the
reduction of a dislocated hip (Ortolani
• With subluxation and lesser degrees of
instability, the flexed hip tends to seat with
• Displacement is noted during adduction
• The key feature of instability is the lateral
movement (toward the transducer) of the
femoral head along the ischium. This results in
increased echogenic soft tissue medially.
• Whereas a normal hip shows slight changes in
the appearance of the medial tissues between
abduction and adduction, with instability, the
thickness more than doubles
• At rest :Normal.
• With stress
and B angle
Ultrasonic evaluation of DDH includes:
I-Morphology assesment (Graf angles)
II-Stability assesment (dynamic exam )
Acquired data depend on proper