It didn’t bother him every day, but after a particularly active day, Sylvester would often complain of leg pain to his dad. The pain was hard to pinpoint, so both Sylvester and his father tended to minimize the problem. Rest almost always made it better. And because Sylvester was slightly overweight, he was quite willing to lie on the couch and play video games while his leg was recuperating. The frequency of his leg pain began to increase and so the father/son team presented to the pediatric orthopedic clinic at Rocky Mountain Hospital for Children. There the physical exam and x-rays confirmed that Sylvester had a slipped capital femoral epiphysis in its very early stages. He was scheduled in the operating room for a simple screw fixation that same day.
What is Slipped Capital Femoral Epiphysis (SCFE pronounced like “skiffee”)
To understand SCFE, you first have to know a little about the hip joint. The hip is a ball-and-socket joint. The ball is at the top end of the thighbone (femur) and the socket is in 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.
In kids and teens who are still growing, there is a growth plate (physis) at the base of the ball (femoral head). This growth plate is made of cartilage which is softer than bone. The growth of the top part of the thighbone depends on this physis.
When a child has SCFE, the femoral head of the thighbone slips at 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’s a slow process with vague pain that is easily dismissed.
Usually, SCFE is classified as:
Stable SCFE. This is referred to as a "mild slip," which causes a child to experience some stiffness or pain in the knee or groin area, and possibly to develop a limp. The pain and the limp usually tend to come and go, worsening with activity and getting better with rest. With stable SCFE, your child is still able to walk although crutches may be necessary.
Unstable SCFE. This is a more severe slip that is usually much more painful. Your child will not be able to bear weight on the affected side, and range of motion tends to be severely limited. An unstable SCFE is also more serious because it can restrict blood flow to the hip joint, leading to a condition called avascular necrosis of the femoral head.
What are the symptoms of Slipped Capital Femoral Epiphysis?
The early warning signs of SCFE are often not recognized or are minimized. Kids will have thigh and knee pain that seems to improve with rest leading the patient and family to believe it’s just an “overuse” problem. SCFE irritates the nerves in the leg causing referred pain (pain that originates in one part of the body but is felt in another). In this case, pain originates in the abnormal hip joint but is felt in the thigh and around the normal knee joint.
What causes SCFE?
No one knows for sure what causes SCFE. However, it is known that it mostly occurs in kids between 11 and 16 years old who are going through a growth spurt. It's more common in boys, though girls can be affected too. It's also more likely to happen in kids who have the following risk factors, all of which can have an effect on bone health:
- obesity (carrying extra weight puts increased pressure on the growth plate)
- endocrine disorders such as diabetes, thyroid disease, or growth hormone problems
- kidney disease
- cancer treatments like radiation and chemotherapy
- certain medications, such as steroids
- a family history of SCFE
How is Slipped Capital Femoral Epiphysis diagnosed?
A thorough physical exam will help the doctor determine that the “knee pain” is truly originating at the hip. Range of motion will be decreased and altered when compared to the unaffected side. X-rays will usually show the subtle change in position associated with the stable SCFE. Occasionally, in a very early presentation, the x-rays may appear normal. An MRI, in this rare case, will show inflammation and edema at the growth plate.
How common is Slipped Capital Femoral Epiphysis?
In terms of musculoskeletal conditions, SCFE is one of the more common with an incidence of 10 per 100,000. Although many cases of SCFE affect only one hip, up to 40% are bilateral (affecting both hips).
How is Slipped Capital Femoral Epiphysis treated?
For both the stable and the unstable SCFE, treatment involves surgical intervention. The stable SCFE can be managed with one or two large screws placed through relatively small incisions to anchor the femoral head in place so that it can slip no further. The unstable SCFE may require a much more extensive surgery to correct the abnormal position and provide stability of the femoral head on the femoral neck.
At the time of surgery, the doctor will assess the risk of the unaffected hip. Especially for patients who are young, there is a high likelihood that the normal hip may also develop SCFE. Sometimes the surgeon will stabilize the other side as well, even if it hasn't slipped yet, just because the risk is high that it could happen. This limits your child’s need for a second anesthesia and a second recovery.
Follow up visits are required to insure that femoral head is healing to the femoral neck. Gradual return to play will be permitted as healing progresses and the surgeon is reassured that the blood supply to the femoral head hasn’t been interrupted by the SCFE.
As a part of his pre-op and intra-op evaluation, his surgeon determined that Sylvester’s overall maturity factors indicated he was at a low risk for the same problem in the other hip. While recovering from surgery at Rocky Mountain Hospital for Children, Sylvester and his family requested counseling from the nutritionist in hopes of adopting healthy food choices at home. The family was enthusiastic to implement a new nutritional plan to help Sylvester and his siblings lose weight and minimize risks of a slipped capital femoral epiphysis. In post-op follow ups, the family was delighted to share that the new eating program had been very successful with all members of the family looking more trim and healthy. The added benefit for Sylvester was that he had no symptoms on the opposite hip and he felt more energetic and athletic.
What is the long-term outlook for my child?
When SCFE is detected and treated early, most kids do well. They will likely receive physical therapy to strengthen the hip and leg muscles, and will continue to have follow-up X-rays to monitor the condition. But in most mild cases, further surgery is not needed.
Kids with unstable SCFE, however, do have a greater chance of developing other problems, 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 realign the hips as they grow.
Of course, there's no way to prevent SCFE in every child. But one thing parents can do to lessen the risk is to encourage kids to keep their weight in a healthy range. Maintaining a healthy weight can go a long way in sparing kids' bones and joints from the excess wear and tear that can weaken and damage them. So if you need help figuring out how to get your child started on a safe diet and exercise plan, talk to your doctor.