Ilizarov's tension-stress effect states that gradual distraction of living tissue produces metabolic activation and regenerative growth. In distraction osteogenesis, the optimal rate and rhythm of distraction is:

• A 2 mm/day in a single daily increment
• B 0.5 mm/day in two increments of 0.25 mm each
• C 1 mm/day divided into 4 increments of 0.25 mm each (four-times daily) ✓
• D 3 mm/day in a single daily increment

Explanation

Ilizarov established that the optimal rate for distraction osteogenesis is 1 mm per day; slower rates (< 0.5 mm/day) lead to premature consolidation and failure to lengthen, while faster rates (>2 mm/day) cause hypovascularised regenerate with poor bone quality and increased non-union risk. Critically, the rhythm matters as much as the rate: dividing the 1 mm/day into smaller increments (ideally 4 × 0.25 mm every 6 hours) produces more uniform mechanical stress and superior regenerate quality compared to a single large daily distraction, as each increment maintains constant tension-stress on the fibroblasts and osteoblasts in the distraction zone.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.