During remodelling of a fracture callus, which cellular mechanism allows angular deformity correction in children under 10 years?
- A Endochondral ossification across the physeal plate
- B Appositional periosteal bone deposition on the concave side and resorption on convex side (Wolff's law) ✓
- C Intramembranous ossification by activated osteoblasts of the endosteum
- D Chondrocyte hypertrophy within the secondary cartilaginous callus
Correct answer: B. Appositional periosteal bone deposition on the concave side and resorption on convex side (Wolff's law)
Explanation
Remodelling corrects angular deformity via Wolff's law: mechanical stresses cause osteoclastic resorption of bone on the convex (tension) side and osteoblastic deposition on the concave (compression) side, straightening the cortex. This process is most active in children under 10 with significant remaining growth, allowing up to 20–30° of residual angulation to remodel completely in femoral shaft fractures. Physeal growth contributes indirectly but is not the mechanism of deformity correction itself.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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