Ultrasound evaluation of femoral rotational deformity following closed reduction and intramedullary nailing for fracture of middle femoral shaft

Abstract

Objective To assess the feasibility and accuracy of the ultrasound evaluation of femoral rotational deformity following closed reduction and intramedullary nailing for fracture of middle femoral shaft.Methods Enrolled in this study were 20 adult patients with fracture of middle femoral shaft who had been treated with closed reduction and intramedullary nailing from January 2012 to January 2013 in our department.They were 12 men and 8 women,aged from 18 to 52 years (average,30.5 years).All the cases were unilateral closed fractures.According to the AO/ASIF classification,8 cases were 32A2,4 cases 32B1,3 cases 32B2,and 5 cases 32C2.Ultrasound examinations were conducted 5 to 7 days postoperation (average,5.7 days).The femoral thick line was observed with the patients in prone position.Next,the minor axis of femoral shaft was observed at both the proximal and distal ends of the fracture.Based on the tip-shaped strong echo images of the femoral thick line on the screen,the angle of ultrasound probe was adjusted to measure the rotational angle of the femoral deformity using an arc angle gauge,60 cm in diameter.The accuracy of ultrasound evaluation was verified by comparing the angles measured by ultrasound examination and by CT scanning.Results The ultrasonic measurement revealed that the average angle of the femoral rotational deformity after operation was 5.82° ± 3.38° in the 20 patients.The CT measurement showed that the average angle of the femoral rotational deformity was 6.00° ± 3.72°.There was no statistically significant difference between the 2 measurements (t =0.808,P =0.429).According to the ultrasonic measurement,14 cases had deformity of distal external rotation,5 deformity of internal rotation,and one was free of rotational deformity,showing a complete agreement with the results of CT measurement.Conclusion Ultrasound evaluation of the femoral thick line at the affected side can accurately detect the rotational condition of the femurs and accurately measure the angle of rotation deformity following closed reduction and iedullary nailing for fracture of middle femoral shaft. Key words: Femoral fractures; Fracture fixation, intramedullary; Ultrasonography; Rotation