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Introduction

Bone mineral density (BMD) meaurement of the proximal femur by dual-energy X-ray absorptiometry (DXA) is widely used in clinical practice. Recently measurment of some proximal femur geometry (PFG) parameters like Hip axis length (HAL), neck–shaft angle (NSA) and femoral neck diameter (FND) measured directly on the DXA image have been adopted as valuable method and showed good reliability. The operator manually determines the HAL and FND as well as NSA. Previous studies on PFG had focused om its ability to predict hip fracture risk as well as to discriminate femoral neck fractures from trochanteric fractures. However, studies on the ability of PFG to distinguish different types of femoral neck fracture are lacking. As the prognosis after undisplaced femoral fractures are much better than those with displaced fractures. PFG parameters used to distinguish femoral fracture types, could be utilized in kombination with BMD to help in decision making regarding further treatment of osteoporosis.

Aim

The aim of this cross-sectional study is to evaluate the ability of PFG, from DXA mesauremet to discriminate displaced from undisplaced femoral neck fractures in young and middle age patients.

Materials and Methods

In this prospective multicenter study, we included 185 consecutive patients between 20–69 years of age with femoral neck fracture (ICD-10 code S7200). The 4 centers were Stockholm Söder Hospital (n = 91), Danderyd Hospital (n = 41), Karolinska University Hospital at Solna (n = 23), and Karolinska University Hospital, Huddinge (n = 30), all in Stockholm, between September 2002 and May 2006. Bone mineral density (BMD) was examined by Dual Energy X-ray Absorptiometry (DXA) using Hologic QDR-4500A densitometer (Hologic, Inc., Waltham, MA. USA) in one centre, GE Lunar DPX-L in another centre and GE Lunar Prodigy (Madison, WI, USA ) in the other two centres. The unfractured hip (femoral neck, total hip, trochanter region and Ward´s triangle) BMD were analyzed. Measurment of Hip axis length (HAL), neck–shaft angle (NSA) and femoral neck diameter (FND) needs to measured directly on the DXA image. Regression analysis will be used to find factors that could predict the type of the fracture. Factors analysed are HAL, NSA, FND, BMI and BMD.

Study design

Cross sectional study.