In Ilizarov distraction osteogenesis for tibial lengthening, the standard distraction rate and rhythm are:
- A 2 mm/day in a single increment; corticotomy performed without a latency period
- B 0.5 mm/day in a single increment; immediate distraction after surgery
- C 1 mm/day in 4 increments of 0.25 mm each; corticotomy performed after a 7-day latency period ✓
- D 1.5 mm/day in 3 increments; no latency period required
Correct answer: C. 1 mm/day in 4 increments of 0.25 mm each; corticotomy performed after a 7-day latency period
Explanation
The optimal distraction rate is 1 mm/day divided into 4 increments of 0.25 mm (or sometimes as frequent as 60 times daily with motorised devices) to maintain the blood supply and stimulate organised fibrous tissue formation in the regenerate zone. A latency period of 5–7 days after corticotomy allows formation of the initial callus before distraction commences. Faster distraction (> 2 mm/day) produces a fibrous non-union; slower distraction (< 0.5 mm/day) causes premature consolidation.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.