Treatment for Trochanteric Fracture of the Femur with Short Femoral Nail: A Comparison between the Asian Intramedullary Hip Screw (IMHS) and the Conventional IMHS.

INTRODUCTION: We usually use short femoral nails for the treatment of trochanteric fracture of the femur. In this retrospective study, we investigated and compared the clinical results of the conventional intramedullary hip screw (IMHS) and the Asian IMHS, which is a redesigned version of the former.

MATERIALS AND METHODS: The subjects were 42 patients; 21 treated with the Asian IMHS and 21 were treated with the conventional IMHS. From the clinical records, we retrospectively investigated the patients' age, sex, in-hospital waiting period for operation, operating time, intraoperative blood loss, walking ability before fracture and at discharge, and complication pertaining to the operation.

RESULTS: The 21 patients (4 men and 17 women) receiving the Asian IMHS and the 21 patients (5 men and 16 women) receiving the conventional IMHS did not differ significantly in mean age, sex ratio, preoperative waiting period, mean postoperative hospital stay, mean operation time, or mean intraoperative blood loss. Among patients receiving the Asian IMHS, the complications of intraoperative fractures of the femur developed in 3 patients and breakage of the implant occurred in 1 patient. No complications occurred in patients receiving the conventional IMHS.

DISCUSSION AND CONCLUSION: Compared with the conventional IMHS, the Asian IMHS is smaller, has increased variations in the shaft/neck angle of the lag screw, and has a titanium-alloy construction, allowing magnetic resonance imaging. The intraoperative fracture may have occurred because of the configuration of the distal interlocking screw in the Asian IMHS. Breakage of the implant likely occurred because the nail was too small in diameter, and too short in length for the unstable AO 31-A3 fracture. If careful attention is paid to the configuration of its distal interlocking screw intraoperatively and a nail of appropriate size is selected, the Asian IMHS is better suited than the conventional IMHS for treating Japanese patients, who generally have a small physique, because of its many variations in size and angle.