Comparison of morphological features in the femur between femoral neck fractures and femoral intertrochanteric fractures

The purpose of this study is to make proximal femur fracture types more predictable by considering morphological features of an acetabulum as well as of a proximal femur in the Japanese population. A retrospective review of radiographs of the proximal femoral fractures was conducted in patients registered from 2010 to 2012, dividing into patients with femoral neck fractures; Group Neck (n = 101), and patients with femoral intertrochanteric fractures; Group IT (n = 99). Intergroup comparison was conducted: age, sex, height, weight, the ratios of femoral intertrochanteric length (IT Length), femoral neck length (Neck Length), femoral neck width (Neck Width), lateral offset length (Offset) to femoral head diameter, neck-shaft angle (N-S angle), and center-edge angle of the acetabulum (C-E angle), adjusting for age. Multiple logistic regression analysis was conducted among these parameters. The Group IT showed significantly older age than the Group Neck. Greater C-E angle in Group IT was observed in the patients in their 80s and 90s years of age. The Group Neck showed greater N-S angle only in the patients in their 80s years of age. In multiple logistic regression analysis, the impact of the age and the C-E angle on the fracture types was similar (odds ratio 1.08, 1.09, respectively, p < 0.01 both). Age, N-S angle, and C-E angle could be independent predictors for determining the proximal femur fracture types.