Abstract:

Objective　The purpose of the study was to observe a structural weak region in the femoral neck in the osteoporosis.　Methods　159 dry femur specimen were collected for this study for identification of the "V"-shaped weak region of trabeculae in the femoral neck. The degree of osteoporosis of the femoral neck specimens were classified according to the Singh index grading. The relationship between the Singh index grading and the "V"-shaped weak region of the neck was assessed. 10 femur neck samples were sectioned in transversal, coronal and sagittal plane for identifying the position of the trabeculae and the "V"-shaped weak region. Femoral neck three-dimensional CT reconstruction was used for identifying bone trabecular contorts.    Results　Singh index 1 (7/159), no of them have the "V"-shaped weak region; as Singh index 2 (23/159), 34.78% of them have the "V"-shaped weak region; as Singh index 3 (42/159), 85.71% of them have the "V"-shaped weak region; as Singh index 4 (48/159), 75% of them have the "V"-shaped weak region; as Singh index 5 (27/159), 29.63% of them have the "V"-shaped weak region. There was not the "V"-shaped weak region of the neck in the Singh index 6. The main pressure trabeculae, the main tension trabeculae, and the minor pressure trabecular bone consisted of WARD triangle in the coronal view, when the main tension trabecular disrupting or missing in osteoporosis, the "V" –shaped weak region is obvious.  Conclusions　Singh index 1-2 is prone to subcapital femoral neck fracture; In Singh index 3-4 tends to produce typical type of femoral neck fracture; In Singh index 5-6, femoral neck fracture is not easy to take place.

Key words: Femoral neck, Structural weak region, Radiological anatomy