A new ultrasound-based method for the assessment of torsional differences following closed intramedullary nailing of femoral fractures

Abstract

Objective: A torsional difference of more than 15 degrees is found in up to 30% of patients following closed intramedullary nailing of femoral fractures. The diagnosis is usually established postoperatively by computed tomography. A torsional deformity of more than 15 degrees should be corrected by early derotation. In order to enable an intraoperative control and possible correction to avoid a second operation for the patient, a new ultrasound-based method suitable for the intraoperative setting has been developed, using the anterior condylar line as a distal reference line.

Design and patients: In a prospective study the torsional difference after closed intramedullary nailing of femoral fractures was measured postoperatively by ultrasound in 32 patients and compared with standard CT readings.

Results: Torsional differences measured by ultrasound and CT showed a high correlation (r = 0.8) and a median difference of less than +/-3 degrees.

Conclusions: By the introduction of the anterior condylar line as a distal reference line femoral torsion can accurately be assessed by ultrasound in a position required for intraoperative control and possible correction.