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Difficulty: MediumOrthopedic Surgery

A 1313-year-old boy is brought to the pediatric clinic by his mother due to a 44-week history of a right-sided limp and intermittent dull pain in his right anterior thigh and knee. He denies any recent trauma, fever, or prior episodes of similar pain. His medical history is unremarkable. His height is at the 50th50^{\text{th}} percentile and weight is at the 97th97^{\text{th}} percentile for his age. Vital signs are within normal limits. Physical examination reveals a waddling, antalgic gait. The right knee examination shows no effusions, joint line tenderness, or ligamentous laxity. On examination of the right hip, internal rotation is significantly restricted compared to the left. When the clinician passively flexes the right hip to 90∘90^\circ, the right thigh obligatorily rotates externally. Radiographs of the pelvis demonstrate posterior and inferior displacement of the right proximal femoral epiphysis. Which of the following is the most appropriate next step in the management of this patient?

  1. Strict non-weight-bearing and prompt percutaneous in situ screw fixationAnswer
  2. B
    Closed reduction followed by application of a hip spica cast
  3. C
    Prescription of nonsteroidal anti-inflammatory drugs and physical therapy
  4. D
    Ultrasound-guided aspiration of the right hip joint
  5. E
    Magnetic resonance imaging of the right knee and lumbar spine

Answer

Strict non-weight-bearing and prompt percutaneous in situ screw fixation is the standard of care to stabilize the physis and prevent further displacement.
The correct intervention is strict non-weight-bearing and prompt percutaneous in situ screw fixation. The patient's clinical presentation (obese adolescent, thigh/knee pain, obligatory external rotation with hip flexion) and radiographic findings confirm the diagnosis of Slipped Capital Femoral Epiphysis (SCFE). In SCFE, the proximal femoral epiphysis displaces posteriorly and inferiorly relative to the metaphysis through the growth plate. The primary goal of treatment is to prevent further slippage by mechanically stabilizing the physis. This is achieved via percutaneous placement of a single screw across the physis (in situ fixation) as soon as the diagnosis is made.

Step-by-Step Solution

1
Analyze the patient's demographics, clinical presentation, and physical exam findings.
The patient is an obese adolescent boy with referred knee/thigh pain, a limp, and obligatory external rotation of the hip with passive flexion, which is the classic presentation of Slipped Capital Femoral Epiphysis (SCFE).
Referred pain to the knee is a common pitfall in diagnosing pediatric hip disorders. Obligatory external rotation is the hallmark physical exam sign of SCFE.
2
Interpret the described diagnostic imaging.
Pelvic radiographs confirm posterior and inferior displacement of the proximal femoral epiphysis.
Plain radiographs definitively diagnose SCFE, eliminating the need for further diagnostic studies like MRI or joint aspirations.
3
Determine the most appropriate definitive management.
Immediate non-weight-bearing status and urgent percutaneous in situ screw fixation.
Surgical pinning stabilizes the physis to prevent further slippage. Attempting closed reduction is contraindicated due to the high risk of avascular necrosis of the femoral head.

Key Concept

Management of Slipped Capital Femoral Epiphysis (SCFE)
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Topics

Orthopedic Surgery

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