What is Slipped Capital Femoral Epiphysis (SCFE)?
Slipped capital femoral epiphysis (SCFE) is a disorder of the adolescent hip in which the upper part of the femur (head) slips through the growth plate (physis) and results in displacement of the overlying head on the neck of the femur. The top part of the thigh bone (femur) is shaped like a ball (femoral head). The ball is connected to the rest of the thigh bone by the growth plate. The head of the femur (capital femoral epiphysis) should sit squarely on the femoral neck and forms most of the “ball” on the ball-and-socket hip joint. In SCFE, the top of the ball slips off the rest of the femur through the growth plate. Think of the ball as being like a scoop of ice cream that falls off its “cone” the thigh bone. The femoral head remains in the acetabulum (hip socket) and the metaphysis (neck of the femur) move in an anterior direction with external rotation. A SCFE can happen suddenly, or slowly over time.
What are the Signs and Symptoms of SCFE?
Patients, usually between the ages of 10 and 14, typically present with groin pain or a limp. However, they may present with only pain in the thigh or knee. The pain may be bilateral (on both sides) as up to 40% of cases involve slippage on both sides. The typical adolescent with a SCFE is overweight but children with normal BMIs (Body Mass Index) can also develop SCFEs. After a first SCFE, when a second SCFE occurs on the other side, it typically happens within one year. Signs may include waddling gait, decreased range of motion and a painful limp. The range of motion is restricted in internal rotation, abduction and flexion. Thus, a patient may have a hard time fully straightening the hip, turning their foot or knee inwards or moving it comfortably. A patient with a SCFE may hold their hip in flexion (bent up) and external rotation (twisted away from the body).
Who is at Risk of SCFE?
Several factors play a role in the development of a SCFE including mechanical and endocrine (hormone related) factors. Mechanical risk factors include obesity and femoral or acetabular retroversion (the alignment of the bones of the hip and thigh that the patient is born with). Obesity is the most significant risk factor. SCFE is most common in adolescent males, especially black males, but also affects females. Endocrine diseases that increase the risk of SCFE include hypothyroidism, hypopituitarism and renal osteodystrophy. Other risk factors include family history, radiation/chemotherapy and mild trauma.
How is SCFE Diagnosed?
The diagnosis is a combination of clinical evaluation and radiographic imaging. 20-50% of SCFE are missed or misdiagnosed on their first presentation because the first symptom may be knee pain and the SCFE is overlooked. X-ray of the pelvis may show the SCFE. The head of the femur appears like a “melting ice cream cone.”
What is the Treatment for SCFE?
Lurie Children’s orthopaedic surgeons have extensive experience in identifying, treating and managing SCFE. Almost all children with the condition require surgery. The procedure involves the placement of one or two screws (“pins”) into the femoral head to prevent further slippage. Pinning of the unaffected side may be recommended if a second SCFE is likely due to age or risk factors. If SCFE is suspected, the patient should be non-weight bearing and placed on bed rest and use a wheelchair.
What are the Complications of SCFE?
Failure to treat a SCFE may result in complete separation of the femoral head on the neck. This may result in avascular necrosis (AVN), hip osteoarthritis, destruction of the hip joint, gait abnormalities and chronic pain. SCFE is also associated with a greater risk of arthritis of the hip joint later in life.
What if I Suspect a SCFE?
Early diagnosis and immediate referral is the goal for the provider who suspects SCFE. X-rays are critical for the diagnosis. It is not recommended that patients with a SCFE go home prior to surgery as the slip may progress and further damage to the hip may occur. Mild slips can rapidly progress to severe slips with significantly worse outcomes. Early treatment is critical to getting the best outcome.