A 13-year-old obese boy presents with a 3-week history of progressive groin pain and antalgic limp. On examination, the affected hip shows obligate external rotation on passive flexion (Drehmann sign). AP radiograph of the pelvis is obtained. The structure marked **B** (Klein line) in the diagram is noted to fail to intersect the lateral aspect of the capital epiphysis. Which of the following is the most appropriate next step in management?
A. Forceful closed reduction followed by spica casting
B. Percutaneous cannulated-screw pin fixation in situ through the centre of the epiphysis
C. Observation with serial radiographs and physiotherapy
D. Traction followed by open reduction and internal fixation
Explanation
Why Percutaneous cannulated-screw pin fixation in situ is correct
The failure of the Klein line to intersect the lateral aspect of the capital epiphysis on the AP radiograph is a pathognomonic sign of slipped capital femoral epiphysis (SCFE). According to Tachdjian's Pediatric Orthopaedics, SCFE is the most common hip disorder of adolescence and requires ALWAYS SURGICAL management. The gold standard treatment is in-situ percutaneous cannulated-screw pin fixation through the centre of the epiphysis to stabilise the slip and prevent further progression. This approach avoids the high risk of avascular necrosis (up to 50% in unstable slips) associated with forceful reduction.
Why each distractor is wrong
Forceful closed reduction followed by spica casting: Attempts at forceful reduction significantly increase the risk of avascular necrosis and are contraindicated in SCFE management. This approach is outdated and dangerous.
Traction followed by open reduction and internal fixation: Traction and open reduction are not standard management for SCFE. Open reduction carries higher morbidity and increased AVN risk compared to in-situ pinning.
Observation with serial radiographs and physiotherapy: SCFE is a surgical emergency, particularly when the Drehmann sign is present and radiographic evidence of slip is documented. Conservative management risks progression of the slip, worsening deformity, and complications including chondrolysis and early osteoarthritis.
High-YieldNEET PG
Klein line failing to intersect the epiphysis on AP radiograph = SCFE confirmed → in-situ percutaneous cannulated-screw pinning is the standard of care; never attempt forceful reduction.
Tachdjian's Pediatric Orthopaedics, 6th ed
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