The biological principle underlying Ilizarov's technique of distraction osteogenesis is that gradual tensile stress applied across a corticotomy stimulates new bone formation. This process is best described as:

• A Endochondral ossification with a fibrocartilage bridge across the distraction zone
• B Intramembranous ossification through periosteal activation at 1 mm/day in 4 increments ✓
• C Enchondral bone formation stimulated by piezoelectric effect
• D Cortical remodeling through Haversian canal expansion

Explanation

Ilizarov distraction osteogenesis uses a low-energy corticotomy (preserving periosteum and medullary vessels) followed by a latency period of 5–7 days, then distraction at 1 mm/day in 4 equal increments (0.25 mm per increment every 6 hours). The new bone forms by intramembranous ossification from activated periosteum and endosteum at the distraction gap — creating a central fibrovascular zone ('interzone') flanked by calcifying columns oriented parallel to the distraction vector. This is distinct from endochondral ossification (fracture healing) because there is no cartilage template.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.