Slipped capital femoral epiphysis is movement of the femoral neck superiorly and anteriorly on the femoral epiphysis. Diagnosis is with radiographs of both hips; sometimes other imaging is needed. Treatment is surgical repair.
Slipped capital femoral epiphysis (SCFE) refers to the superior and anterior movement of the femoral neck upward and forward on the femoral epiphysis.
SCFE usually occurs in early adolescence and seems to have a male preponderance. Obesity is a significant risk factor. Genetic factors also contribute. SCFE is bilateral in one-fifth of patients, and unilateral SCFE becomes bilateral in up to two-thirds of patients.
The exact cause of SCFE is unknown but probably relates to weakening of the physis (growth plate), which can result from trauma, hormonal changes, inflammation, or increased shearing forces due to obesity.
Symptoms and Signs of SCFE
The onset is usually insidious, and symptoms of slipped capital femoral epiphysis are associated with stage of slippage.
The first symptom of SCFE may be hip stiffness that abates with rest; it is followed by a limp, then hip pain that radiates down the anteromedial thigh to the knee. In a prospective cohort study in the United States between 2009 and 2015, 26% of patients presented with knee pain, and 35% presented with thigh pain (1). The true problem (hip) may be missed until slippage worsens.
Pearls & Pitfalls
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In more advanced stages, findings may include pain during movement of the affected hip, with limited flexion, abduction, and medial rotation; knee pain without specific knee abnormalities; and a limp or Trendelenburg gait. The affected leg is externally rotated. If blood supply to the area is compromised, avascular necrosis and collapse of the epiphysis may occur.
Symptoms and signs reference
1. Uvodich M, Schwend R, Stevanovic O, Wurster W, Leamon J, Hermanson A. Patterns of Pain in Adolescents with Slipped Capital Femoral Epiphysis. J Pediatr. 2019;206:184-189.e1. doi:10.1016/j.jpeds.2018.10.050
Diagnosis of SCFE
Plain radiographs
Sometimes MRI or ultrasound
Early hip examination may not reliably detect pain or limitation of movement. If there is clinical suspicion of disease, early radiographic diagnosis of SCFE is vital because the treatment of advanced slippage is difficult.
Anteroposterior and frog-leg lateral radiographs of both hips are taken. Radiographs show widening of the epiphyseal line or apparent posterior and inferior displacement of the femoral head. To help determine displacement, Klein lines (an arbitrary line drawn along the superior edge of the femoral neck in the anteroposterior or frontal view) are drawn on the radiograph on the superior border of the femoral neck. The femoral head will be below the Klein line on the affected side, whereas a significant portion of the femoral head will be above the Klein line on the unaffected side.
Ultrasound and MRI are also useful, especially if radiographs are normal.
Klein lines are drawn on the superior border of the femoral neck in this patient with slipped capital femoral epiphysis (SCFE) of the right hip. Note that the femoral head is below the Klein line on the affected right side, whereas a significant portion of the femoral head is above the Klein line on the unaffected left side.
Treatment of SCFE
Surgical repair
SCFE usually progresses; it requires surgery as soon as it is diagnosed. Patients should not bear weight on the affected leg until SCFE has been excluded or treated.
Surgical treatment consists of screw fixation through the physis.
