Management of hypertrophic femoral diaphyseal nonunion due to sclerotic bone formation (corticalization) at the intramedullary nail tip after dynamization.

The aim of this study was to investigate the effect of the presence of the "cortex sign" (corticalization) in femoral diaphysis fractures determined by the dynamization of nails because of delayed union. The study included 12 patients with a closed transverse femoral fracture (AO 32a3) treated with dynamization (all the screws distal of the nail were removed) because of delayed healing and followed up for at least 2 years. These patients were evaluated for the presence of bone union, cortex-like sclerosis (corticalization) distal to the nail, and the distance of the corticalization from the joint during follow- up after dynamization. The nail lengths and diameters, and time of dynamization were evaluated. In cases that developed pseudarthrosis and were treated with nailing, the length and diameter of the new nails were evaluated. Corticalization and hypertrophic pseudarthrosis were present in 12 patients after dynamization. The old nail was removed and nail exchange was performed with a longer and larger diameter nail to pass the region formed in the cortex approximately 2-3 cm inferior to the old nail. Union was obtained in 3-4 months in all patients. When corticalization is seen during follow up after dynamization is performed because of non-union of a transverse femoral fracture, nail exchange should be performed without further delay. More rigid fixation should be applied with a longer and thicker nail crossing the area of corticalization.