A good, stable connection at the hip joint is what lets us walk, run, jump, and
many other things. But in some kids — particularly
those who are obese
— the thighbone and the hipbone are a little less well connected than they should
be because of a condition called slipped capital
femoral epiphysis(SCFE). SCFE is a shift at the upper
part of the thighbone, or femur, that results in a weakened hip joint.
Fortunately, when caught early, most cases of SCFE can be treated successfully.
About Slipped Capital Femoral Epiphysis
To understand SCFE, it helps to know a little about the hip joint. The hip is a
ball-and-socket joint, which means that the rounded end of one bone (in this case,
the "ball" of the thighbone) fits into the hollow of another bone (the acetabulum,
or cup-shaped "socket" of the pelvis). Ball-and-socket joints offer the greatest range
of movement of all types of joints, which explains why we can move our legs forward,
backward, and all around.
Kids and teens who are still growing also have a growth plate at the top of the
thighbone, just under the "ball" portion (also known as the femoral head) of the joint.
This growth plate is called the physis and it's made of cartilage, which is weaker
than bone. The job of the physis is to connect the femoral head to the thighbone while
allowing the bone to lengthen and grow.
In SCFE, the femoral head of the thighbone slips through the physis, almost the
way a scoop of ice cream might slip off a cone. Sometimes this happens suddenly —
after a fall or sports injury, for example — but often it happens gradually
with no prior injury.
Usually, SCFE is classified as:
Stable SCFE. A stable SCFE causes some stiffness or pain in the
knee or groin area, and possibly a limp that causes a child to walk with a foot outward.
The pain and the limp usually tend to come and go, worsening with activity and getting
better with rest. With stable SCFE, a child still can walk, even if crutches are needed.
Unstable SCFE. An unstable SCFE is a more severe slip that
usually happens suddenly, and is usually much more painful. A child will not be able
to bear weight on the affected side. An unstable SCFE is also more serious because
it can restrict blood flow to the hip joint, leading to tissue death in the head of
Sometimes SCFE can irritate the nerves that run down the leg, causing referred
pain (pain that starts in one part of the body but is felt in another). In
this case, pain begins in the abnormal hip joint but is felt in the normal knee joint.
Some cases of SCFE affect only one hip, but many are eventually found to affect
both hips (be bilateral). When SCFE affects one hip, doctors may closely watch the
other to see if it develops SCFE; or, if that's considered very likely, they might
treat both hips at the same time. Catching SCFE early makes a big difference in how
easily doctors can treat it.
Causes of SCFE
No one knows for sure what causes SCFE. But most cases are in kids between 11 and
16 years old who are going through a growth spurt. SCFE is more common in boys, though
girls can be affected, too.
SCFE is also more likely in kids who have these risk factors, all of which can
affect bone health:
obesity (carrying extra weight puts increased pressure on the growth plate)
endocrine disorders such as diabetes,
thyroid disease, or growth hormone problems
A child thought to have SCFE will see an orthopedic doctor, a specialist in the
treatment of bones. The doctor will do a thorough physical examination, checking the
range of motion of the hips and legs and seeing if there is any pain. The doctor will
also take X-rays
of the hips to look for any displacement at the head of the thighbone.
In rare cases, X-rays will come back normal, but the pain, stiffness, and other
problems will still be there. In these cases, a magnetic
resonance imaging study (MRI) might be ordered. An MRI can catch very early SCFEs,
before they start to slip very far.
SCFE is always treated with surgery to stabilize the growth plate that slipped.
But even before the surgery, the doctor will try to prevent any further slipping by
encouraging rest and the use of crutches to avoid putting weight on the affected leg.
Many doctors recommend admission to the hospital as soon as the SCFE is discovered
to make sure the patient rests, and so surgery can be done as soon as possible.
Surgery for SCFE is done under general anesthesia (when a patient is completely asleep). Using
a fluoroscope — a special X-ray machine that produces a real-time image of the
hip on a TV screen — as a guide, the surgeon will make a tiny incision near
the hip, then put a metal screw through the bone and across the growth plate to hold
it in place. The screw is placed deep into the bone, and cannot be felt by patients
Because some patients have a high risk of an SCFE in the other hip, the surgeon
might also stabilize that side too, even if it hasn't slipped yet.
Doctors decide how much weight can be placed on the affected leg after surgery
based on the severity of the slip. Patients usually can walk with crutches, but those
who have both hips treated may need to use a wheelchair for the first couple of weeks
Most kids do well when SCFE is caught and treated early. Doctors will continue
to order follow-up X-rays to monitor the condition. In the majority of cases, more
surgery isn’t needed.
However, kids with unstable SCFEs have a greater chance of developing other problems
later, such as stiff hips, early arthritis, leg length differences, or avascular necrosis
(where part of the "ball" dies from lack of blood supply). They're also more likely
to require additional surgery to take care of their hip.
Not everyone can prevent SCFE. But reaching and maintaining a healthy weight can
spare bones and joints from the excess wear and tear that can weaken and damage them.
If your child is overweight and you need help developing a safe diet and exercise
plan, talk to your child's doctor.