Fractures of the proximal femur: correlates of radiological evidence of osteoporosis

Objective: Fractures of the proximal femur are common sequelae of osteoporosis, and are responsible for significant morbidity and mortality in elderly patients worldwide. Plain film radiographic assessment methods to assess for fracture risk may be of particular value. Design and patients: The authors present the results of biomechanical testing, radiographic imaging, and histologic exam of 20 embalmed human bone specimens, with implications for clinical correlation of radiologic findings. Authors assessed bone architecture using the Singh Index, using a blinded 3-rater system to reduce bias and measure intra-observer reliability. After loading to failure with ultimate tensile strength (UTS), bone specimens were assessed by fracture location type and by trabecular bone volume (TBV). Results: Singh scoring was performed with Inter-Class Correlation of 0.80 (F=0.24, by ICC Portney Model 2). A statistically-significant difference among the UTS distributions was noted for UTS by Fracture Site (F=4.49, p=0.026, by ANOVA). No significant association of Singh Index with TBV, or TBV with UTS, was observed, although a trend toward greater UTS with higher Singh grade was observed. Conclusions: The authors propose that the Singh Index is a valuable and reliable indicator which may reflect structural integrity in trabecular bone. Fracture site along the femur is associated with tensile strength. The authors, in the light of these findings, address the promise and potential impact of prophylactic hip augmentation in populations at risk for femoral neck pathology.