Book: Hip Sonography: Diagnosis and Management of Infant Hip Dysplasia
Orthopaedic surgeons, paediatricians and radiologists
all deal with the problem of dislocation
and dysplasia of the infant hip. If dysplasia
and displacement of the infant hip are described
together under the heading “Disorders of Hip
Maturation” then together they constitute the
commonest disease of the musculoskeletal system.
These disorders have implications not only
for the child itself and its entire family, but they
are of enormous consequence for public health.
It is currently thought that 9%–10% of all hip replacements
carried out are necessary because of
a hip maturation disorder. Hence the importance
of early detection. Generally, authors agree that
early detection of dysplasia or displacement is
fundamental for adequate treatment. However,
opinion differs widely as to what requires treatment.
Should only displaced or dislocated hips
be treated or should a dysplastic bony acetabulum
without any displacement be treated? How
many resolve spontaneously without treatment?
Should “unstable” hip joints be treated? There is
no consensus about how “instability” should be
defined. Does instability require treatment only
if the femoral head can be dislocated out of the
socket or if, under pressure, the femoral head
shifts within the socket?
Hip ultrasonography with its ability not only
to visualise the unossified parts of the newborn
hip but also to show movement of the femoral
head within the socket has brought about an
enormous improvement in infant hip diagnosis.
Hip ultrasound is practicable, reproducible, and
able to be taught and learnt.
It is easy to be impressed by observing with
ultrasound the movements of the femoral head
in the acetabulum. However, these observations
are purely subjective and can lead to misdiagnosis.
The cartilaginous and bony parts of the hip
joint must be objectively measured and quantified
in relation to the age of the baby, otherwise
sonography ends in catastrophe.