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 pelvis). Ball-and-socket joints offer the greatest range of movement of all types of joints, which is why you can move your legs forward, backward, and all around.
In kids and teens who are still growing, there is also a growth plate at the top of the thighbone (femur), just under the "ball" portion of the joint. This is called the physis, and it's made out of cartilage, which is weaker than bone. The job of the physis is to connect the femoral head (the "ball") to the femur while still allowing the bone to lengthen and grow.
When someone has SCFE, the epiphysis slips off of the top part of the femur, 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 it can also happen gradually, with no previous injury.
Keep in Mind
SCFE is always treated with surgery to stabilize the bone that slipped. But even before the surgery, the doctor will try to prevent any further slippage by recommending rest and the use of crutches to avoid putting weight on the affected leg. During surgery, the doctor stabilizes the top of the thighbone by inserting one or more screws.
All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.