Biomechanical analysis of antegrade and retrograde flexible intramedullary nail fixation of pediatric femoral fractures using a synthetic bone model.

Biomechanical testing was performed to evaluate the stability of simulated transverse and comminuted femoral fractures after retrograde and antegrade flexible titanium intramedullary nail fixation. Ten synthetic adolescent-sized femoral bone models were used. Five underwent retrograde fixation with two C-shaped nails inserted from medial and lateral entry portals. The other five underwent antegrade fixation using one C- and one S-shaped nail through lateral entry holes just inferior to the greater trochanter. Retrograde nail fixation demonstrated significantly less axial range of motion and greater torsional stiffness than antegrade fixation in both transverse and comminuted fracture patterns. However, there appeared to be a biomechanical trend of greater resistance to shortening for antegrade nails.