The interlocking medullary nail widens the range of the indication for medullary osteosynthesis of the femoral shaft fractures.

Twenty one cases with the comminuted fracture of the femoral shaft were reviewed, which had been treated by closed or or semi-open IM nailing at the Department of Orthopedic Surgery, Pusan Paik Hospital from March 1991 to December 1993.

The results were as follows

1. The period of fracture union was 22.1 weeks in Winquist-Hansen Grade III,27.4 weeks in Grade IV , 19.6 weeks in segmental. And its period was 22.6 weeks in closed and 26.2 weeks in semi-open IM nailing.

2. The result of closed interlocking medullary nailing was better and complications were less than semi-open interlocking medullary nailing.

3. The severely comminuted femoral shaft fractures were unstable and there were the risk of shortening, rotation and inadequate reduction. Therefore, when the closed interlocking medullary nailing did not gain the anatomical reduction, it was altemative method to perform semi-open interlocking medullary nailing.

From above result, we conclude that closed interlocking medullary nailing or semi-open interlocking medullary nailing seems to be a favorabel method for treatment of severe comminuted femoral shaft fracture.