[Clinical study on the rotational deformity after interlocking nailing in femur shaft fracture].

Objective: To explore the approach to accurately judge the degree of rotational deformity in femur shaft fracture.
Methods: 110 patients with femur shaft fracture were divided into 3 groups: Group A (n = 62) with the distal end of the fractured femur at the traumatic side at neutral position so as to fix the fracture, Group B (n = 27), with both the distal and proximal ends of the fractured femur at the neutral position so as to fix the femur at an antiversion angle of 15 degrees d, and Group C (n = 21), with the degree of antiversion angle to be controlled to that on the intact side. X ray examination and CT scanning were conducted 3 days after intramedullary nailing to measure the degree of the antiversion angle on both sides. The difference between the degrees of antiversion angle at the 2 sides was considered the rotational deformity of the femur shaft after the nailing. The antiversion angles of the femurs at both sides of 11 healthy persons were measured as controls.
Results: The biggest value of antiversion angle was 26 degrees , the smallest value was 8 degrees , the average value at the left side was 12.8 degrees , and the average value at the right side was 12.45, and the biggest difference between the 2 side was 7 degrees in the control group. The average antiversion angle of the femur was 14.67 degrees , the biggest value was 51 degrees , and the smallest value was -24 degrees at the traumatic side; and the average antiversion angle of the femur was 14.27 degrees , the biggest value was 40 degrees , and the smallest value was -23 degrees at the intact side in the treatment groups. 53% and 52% of the patients in Groups A and B showed a rotational deformity < 10 degrees , and 9% and 11% of them showed a rotational deformity > 20 degrees , significantly different from those in the control group (all P < 0.05). The rotational deformity was < 10 degrees in all patients of Group C, not significantly different from that of the control group (P > 0.05).
Conclusion: Clinically about half of the femur shaft fractures are fixed in the position of rotational deformity > 10 degrees after nailing. The rotational deformity of femur shaft fracture should be prevented by comparing the antiversion angle on the intact side so as to achieve more reliable adequate reduction.