The New Proximal Femoral Nail Antirotation-Asia: Early Results

Abstract

The proximal femoral nail antirotation system was introduced by the Arbeitsgemeinschaft fur Osteosynthesfragen/Association for the Study of Internal Fixation (AO/ASIF) in 2003 and is suitable for treating unstable trochanteric fractures. However, proximal femoral nail antirotation was designed according to the geometric proportions of the White population, and it is known that important differences exist between Asians and Americans with regard to femoral geometry. Reports of serious postoperative complications also exist when used for the elderly Asian population. Therefore, geometrical mismatch between proximal femoral nail antirotation and the femora of Asians has led the AO/ASIF to design a new proximal femoral nail antirotation for Asia with adapted sizes and geometry. This article reports early clinical results of using proximal femoral nail antirotation for Asians in 84 consecutive patients to stabilize unstable trochanteric fractures (AO classification, 31.A2 and A3). Patients were followed up for an average 8 months (range, 4-11 months). Intraoperative and postoperative complications, surgical details, and outcome measurements were evaluated. Fractures were treated by closed reduction and intramedullary fixation. The proximal femoral nail antirotation Asia position was ideal in 80 cases (95%). No patients showed complication related to the mismatch between the nail and femora. The mean time to bone healing was 14 weeks. Functionally, 90% of the patients regained pretrauma mobility. According to the Harris hip scoring system, 63 patients (78%) had an excellent or good outcome. The new proximal femoral nail antirotation Asia yields better results in the treatment of unstable trochanteric fractures in elderly patients by closely matching Asian femoral anatomy and thereby reducing complications related to the implants.