The morphology of the femur in elderly Japanese females: Analysis using 3D

While various implants are currently used for the treatment of femoral trochanteric fractures in Japan, ‘mismatches’ have been known to occur between patient and implant type. The purpose of this study is to identify morphological characteristics of elderly Japanese females, both in terms of the shape of proximal femur and its anterior curvature in order to evaluate the suitability of implants for treatment of femoral trochanteric fractures using 3D-computed tomography (CT) scanning. This study used CT scan data taken from 50 elderly females (aged 70 years or older). Neck–shaft (NS) angle and height of the greater trochanter (GT) were measured under defined conditions (TPI: theoretical plane to place implant). Anterior curvature of the femoral shaft was also measured. On average, the NS angle was found to be 128.1° and GT height was 62.4 mm. Average curvature radius was 1040 mm. As for the NS angle, the centrum-collum-diaphysis angles of existing implants (125° or 130°) are reasonable. In elderly Japanese patients, the proximal femur shows specific characteristics. As GT height is very short, the implant may easily interfere with the lateral cortex. Additionally, the curvature radius calculated (1040 mm) was smaller than that of past reports, indicating strong curvature in the Japanese elderly. Our measurement results are potentially useful in the avoidance of intraoperative trouble caused by mismatch of implants