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Zorluk: ZorPediatric Musculoskeletal Disorders

A 12-year-old boy is brought to the outpatient clinic by his parents due to a 4-week history of dull, aching pain in his left knee. The pain worsens after physical activity and improves with rest. He denies any direct trauma, falls, or fevers. His medical history is unremarkable, and his BMI is 32 kg/m². Vital signs are within normal limits. On physical examination, the patient has an antalgic gait and walks with the left foot pointing slightly outward. Inspection and palpation of the left knee reveal no erythema, swelling, or focal point tenderness. Anterior drawer, posterior drawer, and McMurray tests of the knee are negative. When the patient is placed in the supine position and the left hip is passively flexed to 90 degrees, the thigh obligately rotates externally. Which of the following is the most appropriate next step in diagnosis?

  1. Anteroposterior and frog-leg lateral radiographs of the pelvisCevap
  2. B
    Magnetic resonance imaging of the left knee
  3. C
    Measurement of erythrocyte sedimentation rate and C-reactive protein levels
  4. D
    Diagnostic arthrocentesis of the left knee
  5. E
    Reassurance and scheduling physical therapy for patellofemoral pain syndrome

Cevap

Anteroposterior and frog-leg lateral radiographs of the pelvis
The patient's clinical presentation is highly suspicious for Slipped Capital Femoral Epiphysis (SCFE), an orthopedic disorder common in obese adolescents where the proximal femoral epiphysis displaces relative to the femoral neck. A classic diagnostic pitfall is that pathology of the hip often refers pain to the thigh or knee via the sensory branches of the obturator nerve. The physical exam finding of obligate external rotation during passive hip flexion (Drehmann sign) strongly localizes the pathology to the hip, despite the patient's complaints being isolated to the knee. The most appropriate next diagnostic step is to obtain anteroposterior and frog-leg lateral radiographs of both hips (pelvis) to identify the epiphyseal slip.

Adım Adım Çözüm

1
Analyze the demographic and clinical presentation.
The patient is an obese 12-year-old male with chronic knee pain, an antalgic gait, and outward pointing of the foot.
Identifying the at-risk demographic (obese adolescent) is critical for forming the differential diagnosis for pediatric musculoskeletal pain.
2
Evaluate the physical examination findings.
The knee exam is completely normal, but passive flexion of the hip results in obligate external rotation (Drehmann sign).
This localizes the true pathology to the hip joint. Pain in the knee is referred pain mediated by the obturator nerve.
3
Determine the most likely diagnosis and the next best step to confirm it.
The presentation is classic for Slipped Capital Femoral Epiphysis (SCFE). The definitive diagnostic modality is bilateral hip radiographs.
Bilateral imaging (anteroposterior and frog-leg lateral views) is required to visualize the posterior and inferior displacement of the femoral epiphysis and to evaluate the contralateral hip, which is often asymptomatically involved.

Anahtar Kavram

Slipped Capital Femoral Epiphysis (SCFE) often presents as referred thigh or knee pain. The physical exam finding of obligate external rotation during passive hip flexion strongly localizes the pathology to the hip, requiring anteroposterior and frog-leg lateral radiographs of the pelvis for diagnosis.
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Pediatric Musculoskeletal Disorders

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