Femoral malrotation after unreamed intramedullary nailing: an evaluation of influencing operative factors.

OBJECTIVE:
The objective of this study was to determine which clinical factors influence the presence and extent of femoral malrotation during unreamed nail insertion performed without a fracture table.

DESIGN:
Retrospective chart review.

SETTING:
Academic trauma center.

INTERVENTION:
Patients were treated statically locked femoral nails inserted without reaming in either a retrograde or antegrade manner without the use of a fracture table between April 1, 2000, and December 31, 2005. All patients received postoperative computed tomography scans. Institutional radiographic threshold for revision surgery was 15° of either internal or external rotation.

MAIN OUTCOME MEASUREMENTS:
Postoperative computed tomography measurements of rotation were compared with the opposite side. Patients were grouped by 1) Orthopaedic Trauma Association fracture classification; 2) closed versus mini open reduction; 3) surgeon experience; 4) antegrade versus retrograde femoral nail; and 5) time of day surgery performed (day shift versus night shift). The following parameters were measured from the chart and x-ray: rotational malalignment, x-ray time, and duration of surgery.

RESULTS:
There were 82 femurs in 82 patients, 59 men and 23 women, with a mean age of 32 years (range, 17-83 years). Eighteen femurs (22%) showed a malrotation of greater than 15°. Seven were internally malrotated (mean, 23°; range 16°-32°), whereas 11 were externally malrotated (mean, 24.2°; range, 16°-39.7°). After clinical examination, only 11 of the 18 patients (61%) underwent revision surgery, six patients for external malrotation (mean, 27.47°; range, 21.9°-39.7°) and five for internal malrotation (mean, 23.6°; range, 16°-32°). Malrotation varied significantly with fracture severity with Type C averaging 19.4° (24 patients), Type B 9° (26 patients), and Type A 6.6° (32 patients). No difference was found between an open and closed technique nor the experience of surgeon or the type of implant. There was a significant difference depending on the time of surgery in which an average malrotation of 15.2° (14 patients) was found on the night shift and an average malrotation of 10.3° (68 patients) was found during the day.

CONCLUSION:
Rotational malalignment greater than 15° was found in 22% of femurs treated in this study. Fracture comminution and time of day the surgery was performed had the greatest effect on the severity of malrotation.