In this lecture, we will discuss structural leg problems of infancy. Let’s start with developmental
dysplasia of the hip. In children with this problem, they will have a partial or complete dislocation
or subluxation of the femoral head out of the acetabulum. As you can see here in this figure,
the first patient is normal. That femoral head is sitting perfectly in the acetabulum. In the next case,
the head is starting to sublux. It’s starting to move out but it hasn’t moved out yet. The next case
is a low dislocation. It’s dislocated but the femoral head is still low and close to the acetabulum.
In the last case which is more severe, this is a high dislocation where the hip has come completely out
and is fairly far from the acetabular space. So, this affects 1 in 1000 births in Caucasians
and is less common in African-Americans and other races. In an older child, the problem is
that they can become fixed bony changes in their hip such that they’re really not able to use
that hip well and may be unable to ambulate. This disease is more common in infants with cramped
intrauterine environment, so for example, children with a breech presentation. It’s much more common
in females than it is in males. There are some long term complications of developmental dysplasia
of the hip. They may develop an osteoarthritis of the hip later on in life. This can be a painful condition.
They may have an abnormal gait. They may have decreased mobility. They may develop flexion
contractures that can further render them less able to move. The way developmental dysplasia
of the hip is detected in a child is through two maneuvers which are highly likely to appear on a test.
These are called the Ortolani and Barlow procedures. Let’s go through what they are.
Basically, the Ortolani procedure is when you try to dislocate the femoral head out of the hip
by pressing down. The Barlow is then trying to relocate the hip with a twisting motion.
You can see in this picture a doctor performing an Ortolani and Barlow procedure. They’ve already tried
to dislocate the hip. Now, they are relocating it. They may feel a clunk noise as that hip gets relocated
into the acetabular space. This test, while cited highly on exams actually has a reasonably high false
positive rate. Oftentimes, hips can sublux in this period of infancy without any long term sequelae
and doctors can feel slight mobility to that hip. They may be concerned there’s a problem when in fact,
there isn’t. There should be a lot of laxity in a dislocated hip. A perhaps more accurate way to test
for a dislocated hip when it’s in the dislocated state is a leg length discrepancy. Since they bend
both legs such the child would be in a sitting position if they were on a chair and measure the height
of the knees as they lie on their back. This should be the same. If there's a difference, it’s possible
that lower leg has been dislocated posteriorly. So, when do we test for problems in dysplasia of the hip?
Well, the best time to ultrasound a hip is after six weeks and before four months. The reason we don’t
like to check for this problem before six weeks is that there are high rates of false positives.
Additionally, after four months, the ultrasound is no longer the test of choice. Now, it’s probably
better to get an X-ray, both a frog leg and AP view of the bilateral hips. If a patient does have
developmental dysplasia of the hip, early detection is useful because we can do a non-surgical approach.
These patients should be referred to a pediatric orthopedist. The doctor will do the early treatment
of placing the child in a Pavlik harness. The Pavlik harness as pictured here is successful
about 90% of the time. So, this is an effective way of treating this problem. By placing the child
in this harness for a long period of time, they’re able to function. Diaper care can continue.
That hip will now grow better into that space without any required surgery.
However, in severe cases or cases where there’s a delay in diagnosis, surgery may be necessary.