Examkin

Question

Difficulty: MediumPediatric Musculoskeletal Disorders

A 13-year-old boy is brought to the clinic by his mother due to a 3-week history of right knee pain and a progressive limp. He describes the pain as a dull, constant ache that worsens with physical activity. He denies any recent trauma, fever, chills, or weight loss. His medical history is unremarkable. He is at the 95th percentile for weight and 50th percentile for height. Vital signs are within normal limits. On physical examination, the right knee has no effusion, erythema, warmth, or tenderness to palpation. Ligamentous and meniscal testing of the knee is unremarkable. When asked to walk, the patient demonstrates an antalgic gait. During range of motion testing of the right lower extremity, passive flexion of the right hip results in obligatory external rotation of the thigh. Which of the following is the most appropriate next step in management?

  1. Bilateral hip radiographsAnswer
  2. B
    Radiographs of the right knee
  3. C
    Arthrocentesis of the right knee
  4. D
    Reassurance and limitation of physical activity
  5. E
    Serum erythrocyte sedimentation rate and C-reactive protein

Answer

Bilateral hip radiographs are the most appropriate next step to diagnose Slipped Capital Femoral Epiphysis.
The correct answer is bilateral hip radiographs because this patient's presentation is pathognomonic for Slipped Capital Femoral Epiphysis (SCFE). SCFE typically occurs in obese adolescents and frequently presents with insidious onset of a limp and referred pain to the ipsilateral thigh or knee. The physical exam finding of obligatory external rotation of the thigh during passive hip flexion is a classic sign of SCFE. The appropriate next step to confirm this diagnosis is obtaining bilateral anteroposterior and frog-leg lateral radiographs of the hips.

Step-by-Step Solution

1
Analyze the patient demographics and symptoms.
The patient is an obese 13-year-old adolescent with atraumatic chronic knee pain and a limp.
Identifying the demographic profile points strongly toward specific age-stratified pediatric musculoskeletal disorders, such as SCFE.
2
Evaluate the physical examination findings.
The knee exam is completely normal, but passive flexion of the right hip causes obligatory external rotation.
A normal knee exam with an abnormal hip exam indicates referred pain from the hip, which is a classic presentation of hip pathology mediated by the obturator nerve.
3
Determine the most likely diagnosis and the appropriate diagnostic test.
The presentation is classic for Slipped Capital Femoral Epiphysis (SCFE). Bilateral AP and frog-leg lateral radiographs of the hips are the required diagnostic imaging.
Hip radiographs confirm the slippage of the femoral head relative to the femoral neck. Bilateral imaging is needed because SCFE can frequently be bilateral or asymptomatic on the contralateral side.

Key Concept

Slipped Capital Femoral Epiphysis (SCFE) frequently presents with referred knee or thigh pain. A normal knee exam coupled with obligatory external rotation of the hip during flexion is highly suspicious for SCFE, requiring prompt bilateral hip radiographs.
Estimated Time:1m 0s
Rate this question

Topics

Pediatric Musculoskeletal Disorders

More questions from this topic