Quantitative Local Topological Texture Properties Obtained from Radiographs of the Proximal Femur in Patients With Pertrochanteric and Transcervical Hip Fractures

The incidence of osteoporosis and associated fractures becomes an increasingly relevant issue for the public health institutions of industrialized nations. Fractures of the hip represent the worst complication of osteoporosis with a significantly elevated rate of mortality. Prediction of fracture risk is a major focus of osteoporosis research and, over the years, has been approched from different angles. There exist two distinct subtypes of transcervical and pertrochanteric hip fracture that can be distinguished on the basis of the anatomical location of the injury. While the epidemiology of hip fractures has been well described, typically, little or no distinction is made between the subtypes. The object of this study was to determine whether local topological texture properties based on the Minkowski Functionals (MF) obtained from standard radiographs of the proximal femur in patients with hip fracture can be used to differentiate between the two types of fracture pattern. The texture features were extracted from standardized regions of interest (femoral head, neck, and pertrochanteric region) in clinical radiographs of the hip obtained from 90 post-menopausal women (69.8 +/- 7.9 yrs). 30 of the women had sustained pertrochanteric fractures, 30 had transcervical hip fractures and 30 were age-matched controls. We determined an optimized topological parameter MF2D(loc) using an integrative filtering procedure based on a sliding-windows algorithm. Statistical relationship between the fracture type (pertrochanteric/transcervical) and the value of MF2D(loc) was assessed by receiver-operator characteristic (ROC) analysis. Depending on the anatomical location of the region of interest for texture analysis correct classification of tanscervial and pertrochanteric fractures ranged from AUC = 0.79 to 0.98. In conclusion, quantitative texture properties of trabecular bone extracted from radiographs of the hip can be used to identify patients with hip fracture and to distinguish between pertrochanteric and transcervical fracture types. The degree of correct classification varies with choice of anatomical site for texture analysis. The results of our study may help to understand the mechanism of the two types of hip fracture.