A 35-year-old male sustains a closed femoral shaft fracture. Intramedullary nailing is planned. The reamer diameter is 1 mm larger than the final nail diameter. Which biomechanical principle does reaming achieve in this scenario?

• A Increase in bending stiffness by enlarging the medullary canal
• B Creation of endosteal contact points that distribute load and improve rotational stability ✓
• C Reduction of cortical vascularity to stimulate periosteal new bone formation
• D Elimination of the tension band effect by converting eccentric to axial loading

Explanation

Reaming enlarges the medullary canal, allowing a larger-diameter nail to achieve multiple cortical contact points along the diaphysis. These contact points distribute axial and rotational loads, improving torsional stability and reducing nail-bone stress concentration. While reaming temporarily disrupts endosteal blood supply, periosteal circulation compensates; the primary biomechanical benefit is improved nail fit and load sharing, not deliberate vascular disruption to stimulate periosteal bone.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.