Ilizarov's law of tension-stress states that gradual distraction osteogenesis generates new bone formation. The standard distraction rate and rhythm used in clinical practice is:

• A 1 mm per day in 4 sessions (0.25 mm each) ✓
• B 1 mm per day in 2 sessions (0.5 mm each)
• C 2 mm per day in 2 sessions (1 mm each)
• D 0.5 mm per day in 2 sessions (0.25 mm each)

Explanation

Ilizarov established that distraction at 1 mm per day, divided into 4 equal increments of 0.25 mm each (or at minimum 3–4 increments), produces optimal distraction osteogenesis with consistent new bone formation and minimal risk of premature consolidation or non-union. A rate faster than 1 mm/day risks fibrous non-union (tissue cannot keep pace); slower than 1 mm/day risks premature consolidation before the desired length is achieved. The latency period (waiting 5–7 days after corticotomy before beginning distraction) allows adequate callus formation.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.