In the treatment of tibial shaft fracture with intramedullary nail. reaming effectively lengthens the isthmus of the tibia and there by extends the number of fractures amenable to this technique.

Reming process, however, destroys the endosteal blood supply, may impair bony union and provecate infection in open fracture.

Eighty-eight cases of tibial shaft fractures treated with reamed nail(56 cases) and unlearned nail(32 cases) from January 1991 to August 1994 at Yonsei Medical Center were analyzed.

Average follow-up period was 7.3 months.

Results were as follows

1. In closed fractures, there was no difference in union time between reamed and unlearned group, and low energy injury group had shorter union time than high energy injury group.

2. In open fractures, unlearned group had shorter union time than reamed group.

3. Unlearned group had less complications such as infection and delayed union, and had more cases of interlocking screw breakage(3 cases) which did not dusturb the bony union.

In conclusion, unlearned tibial nailing was useful method to treat not only open fracture but also closed fracture.