The influence of entry point and radius of curvature on femoral intramedullary nail position in the distal femur.

AIM Perforation of the anterior cortex during femoral intramedullary nailing can be a major complication. We aim to determine the influence of entry point and radius of curvature on intramedullary nail position in the distal femur using a synthetic bone model. METHODS Using synthetic femora, the greater trochanter was measured and entry points marked in two planes. A standard recommended technique was used to insert two different Stryker Gamma 3 intramedullary nails of different radius of curvature. The synthetic femora were sectioned and the centre of nail to anterior cortex distance (CAD) was measured. Statistical interpretation of the results was performed using linear regression analyses. RESULTS We found that the more posterior entry points led to a more anterior placement in the distal femur in both nails of differing radius of curvature (11 mm and 13.5 mm CAD). The smaller radius of curvature led to a more central placement of the nail tip in the distal femur. CONCLUSION Anterior penetration of the distal femur can be minimized by a more anterior entry point and with the use of a femoral intramedullary nail with a smaller radius of curvature.