Slipped Capital Femoral Epiphysis(SCFE) is an uncommon but often overlooked condition affecting a childs hip.
SCFE is a condition where the growth plate at the upper end of the femur is weakened. The femoral head will slip off the femoral neck at the growth plate.
The growth plate is naturally slightly weaker then the bone around it. In SCFE, the growth plate separates allowing the bone on either side to displace. The femoral head will stay in the hip socket and the femoral neck will slide superiorly and anteriorly. Most of the time, this happens slowly over weeks or months, but is can also happen rapidly.
The x-ray shown above demonstrates a SCFE. Notice that no part of the femoral head is above Kleins line. In a normal hip, some part of the femoral head will show above Kleins line. Also, notice on the right image that the femoral head seems to be sliding right off the femoral neck.
This condition usually effects adolescents around the time they are reaching puberty. Males are effected more frequently then females and the adolescents with SCFE are usually overweight. Once SCFE is diagnosed in one hip, there is approximately a twenty-five percent chance that the opposite hip will be effected, usually within eighteen months from the initial diagnosis, so after treating one hip, I keep a close eye on the other side over this time period.
SCFE is broadly classified into two groups, stable and unstable. If the child can bear weight on the effected leg, the SCFE is said to be stable. If the child can not bear weight on the effected leg, the SCFE is said to be unstable. The classification of SCFE between stable and unstable is important because the complications associated with SCFE are much more frequently seen in unstable slips compared to stable ones. There will be more about these complications shortly.
Most commonly a child with SCFE will present to the office complaining on ongoing hip pain and an occasional limp especially after a lot of activity. These symptoms may have been present for months and are usually getting worse prompting a visit to the doctor. The child does not always complain of hip pain. It is well documented that a child with SCFE may complain of knee pain. Any early adolescent child with knee pain must have a thorough hip examination as part of their overall evaluation.
On physical examination, the child will usually have their hip externally rotated while laying on their back. There will be pain and limitation of hip motion especially internal rotation. There may also be a small leg length discrepancy with the effected leg being slightly shorter.
SCFE requires urgent treatment. If the hip is stable, then you want to treat the hip before it has a chance to become unstable. Treatment involves insitu pinning of the hip. Insitu pinning involves placing a screw across the growth plate into the femoral head which will stop the slipping and cause the growth plate to close. Once SCFE is diagnosed, the patient should be admitted into the hospital and placed on bedrest. The surgery should be done when there is reasonable operating room available
Once the hip slips, it is pinned without being reduced. Reducing the hip to an anatomic position can cause serious complications, such as avascular necrosis (AVN). The effected hip will have a not have the same range of motion as the unaffected side, because its anatomy has been changed by the slipping. Still, when treated properly, most children resume normal activities without pain.
AVN is the most serious potential complication from SCFE. This means that the blood supply to part of or the whole femoral head is disrupted. This causes cells within the bone to die, leading to bone weakness, collapse, pain and decreased function. If the AVN is severe, there are very few good treatment options for the child. Some type of osteotomy or a hip fusion may be required. It is best to try to avoid AVN.
Another potential complication is called chondrolysis. Chondrolysis is the term used to describe the breakdown of cartilage that can occur if the hip screw is protruding into the hip joint. Hip range of motion will rub the end of the screw against the hip cartilage causing it to break down and become painful. The screw is removed or revised if this happens.
Once a childs hip is pinned, I will limit their activities for at least three months as the growth plate begins to close. For a severe slip, I will keep the child on crutches for the first four weeks.