A 35-year-old man sustains a closed diaphyseal femur fracture in a road traffic accident. Intramedullary nailing is planned. Which of the following best describes the mechanism by which reamed intramedullary nailing achieves fixation stability?

• A Three-point bending resistance within the medullary canal plus proximal and distal interlocking screws ✓
• B Screw-plate compression across the fracture site
• C Load sharing through callus bridging the fracture gap
• D Cerclage wire tension banding the periosteal sleeve

Explanation

An intramedullary nail achieves primary stability through three-point contact with the endosteum of the medullary canal, resisting bending and torsional forces. Interlocking screws proximally and distally prevent rotation and shortening. This is a load-sharing device, not load-bearing like a plate; callus forms secondarily. Cerclage wires are not part of standard IM nail technique.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.