In septic arthritis of the hip in a neonate, the mechanism of joint destruction that necessitates urgent joint drainage is:
- A Intracapsular pressure-related vascular compromise of the femoral head combined with proteolytic enzyme-mediated cartilage destruction ✓
- B Direct cartilage toxicity from bacterial exotoxins only
- C Periosteal elevation causing avascular necrosis
- D Synovial membrane fibrosis leading to adhesive capsulitis
Correct answer: A. Intracapsular pressure-related vascular compromise of the femoral head combined with proteolytic enzyme-mediated cartilage destruction
Explanation
In neonatal septic arthritis of the hip, increased intracapsular pressure from purulent effusion compresses the circumflex femoral vessels (which supply the femoral head in neonates as the blood supply traverses intracapsularly), causing ischemia and avascular necrosis of the femoral head. Simultaneously, neutrophil-derived proteolytic enzymes (collagenase, hyaluronidase) rapidly degrade articular cartilage. This dual mechanism makes neonatal hip septic arthritis an orthopedic emergency requiring surgical joint drainage within 6–8 hours to prevent femoral head destruction.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
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