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

Purpose: 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.

Methods: 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.

Results: 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).

Conclusions: Age, N-S angle, and C-E angle could be independent predictors for determining the proximal femur fracture types.