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Slipped Upper Femoral Epiphysis

Slipped upper femoral epiphysis (SUFE) is a condition of the hip that usually affects adolescents, in which the physis (growth plate) of the femur (thighbone) is weak and the epiphysis (head part of bone) becomes separated from the rest of the bone. The epiphysis is located at the top of the femur, and the femoral head will usually slip backward and inward in SUFE.

Facts

SUFE affects approximately 2-10 adolescents/100,000 in the U.K

SUFE usually occurs in early adolescents during a rapid growth spurt (age10-13
in females, 12-16 in males)

SUFE is BILATERAL (involves BOTH hips) in approximately 25-40% of patients

The incidence of SUFE is higher than normal in children with the following risk factors:

  1. Male Sex (approx 60-65% or cases occur in males)
  2. Obesity (most children are greater than the 95% for their weight)
  3. Pacific Islanders (have the greatest prevalence of SUFE of any ethnic
    group or geographical region)
  4. African-Americans (the condition is approximately 2X more common
    in African-Americans compared to Caucasians)

What causes SUFE?

There are many theories as to the cause of SUFE, however it is believed be caused by both mechanical as well as constitutional factors. Most likely, SUFE is caused by multiple factors (multifactorial) including local trauma, obesity overcoming the physeal plate (growth plate), inflammatory factors, and possible endocrine abnormalities (increased incidence seen in hypothyroidism, panhypopituitaryism, renal osteodystrophy).

Obesity seems to be the strongest risk factor for SUFE, and it is believed that the child’s increased weight causes excessive mechanical stress on the physis (growth plate). Many studies have shown that SUFE tends to occur during an adolescents’ rapid growth spurt, as the growth plate appears to be most vulnerable to shear stress and injury at this time. Slipped upper femoral epiphysis NEVER occurs once the growth plate has closed.

How is SUFE diagnosed?

The diagnosis of SUFE is made based on your child’s symptoms, physical examination, as well as radiographs (x-rays) of the pelvis. Typically, a child with a stable slipped upper femoral epiphysis has a history of intermittent limp and pain of several weeks duration that is often poorly localized to the thigh, the groin, and often the knee.

Frequently, a vague history of prior trauma calls attention to the limp and pain. As the epiphysis continues to slip, there may be decreased range of motion and a pronounced limp. There may also be automatic external rotation of the lower extremity with flexion of the hip.

Patients with unstable acute slipped upper femoral epiphysis usually have an acute onset of severe pain, often after a sports-related trauma or fall. They will be unable to bear weight on the affected leg. Although the diagnosis is often made with plain x-rays, further radiographical studies such as an MRI may be necessary.

What is the treatment for SUFE?

It is important to prevent the femoral head (top of the thigh bone) from further slippage. Early diagnosis of SUFE provides the best chance to achieve the treatment goal of stabilizing the hip. The standard treatment for SUFE is to place a single screw across the growth plate through a very small incision on the thigh. This procedure is commonly referred to as a percutaneous pinning. However, if the slip is severe, a more involved procedure or corrective surgery may be necessary.

The goal of treatment is to prevent increasing deformity of the hip or increased slipping of the epiphysis. Therefore, the goal of surgery is to stop slipping while the growth plate is still open. Once the growth plate has closed, no further slipping can occur.

Your child will be admitted to the orthopaedic service and taken to the operating theatre for the percutaneous pinning. He/She will likely be in the hospital for 24-48 hours after the surgery. They will then be discharged with instruction to be non-weightbearing for 6 weeks. There will be physiotherapy during this time to encourage gentle hip movements. At 6 weeks there will be a follow up and if all is well, gradual return to all activities. The child will be followed up episodically until the growth plate fuses.

Because of the high association of bilaterality seen in SCFE (approx 25-40%), patients will need to be closely monitored to ensure that the OTHER hip does not slip. If the patient is to develop any hip, groin, or knee pain in the other leg (especially in the first 6-12 months after surgery), he/she should be evaluated by the orthopaedic surgeon as soon as possible.

What are the potential complications of SUFE?

The majority of patients with stable slips that have undergone percutaneous pinning do not have any complications. With early recognition and timely treatment, the long-term prognosis is good for patients with a stable SUFE. However, there are several potential complications associated SUFE. The most common are avascular necrosis (AVN) of the femoral head (top of the thigh bone) and chondrolysis. Avascular necrosis is loss of blood supply to the head of the femur, causing death of the bone. This condition is much more likely if the slip is severe or unstable. Patients with avascular necrosis will often have early onset arthritis of the hip. Chondrolysis or loss of articular cartilage of the hip joint is another potential complication of SUFE. This may cause a loss of hip motion, flexion contracture, and pain. This is a relatively rare complication that again is seen more frequently in patients with a severe or unstable slip. The orthopaedic surgeon will see the patient in follow-up visits, and x-rays will be obtained to evaluate for these potential complications.

There is also a link between the severity of the slip and the development of osteoarthritis of the hip in the future. With an increasing awareness of the problem of hip impingement, this is something that is being looked at closely with a view to changing the shape of the hip surgically if necessary.