A new approach to accurately and inexpensively predict hip fracture.
ImaTx HFPS (Hip Fracture Prediction System) quantitatively predicts loads that fracture cadaver proximal femur (hip).
HFPS provides the greatest potential for providing an accurate, noninvasive measure of individual hip fracture presenting an entirely new paradigm for managing patients with osteoporosis. This paradigm is one in which individualized fracture risk drives the need for therapy, the type of drug(s) used, and even the duration of therapy
Previously, there has been no available technology to measure individual fracture risk.
Only 5 percent of falls result in fractures suggesting that there are other non-fall variables that are likely co-determinants of hip fracture such as impact location, bone density and architecture, and proximal femoral geometry that influence the structural capacity of the femur.
Bone mineral density measurements (BMD) successfully identify subjects at risk for fracture and can help physicians select those individuals who will derive greatest benefit from therapy. However, overlap exists in the distribution of BMD of patients with and without osteoporotic fracture, and BMD does not accurately predict the presence of fractures. Thus, factors other than BMD contribute to fracture risk. Key among those factors is alterations and disruptions of trabecular structure.
Substantial overlap exists in the distribution of BMD of patients with and without osteoporotic fracture and that BMD does not accurately predict the presence of osteoporotic fractures and cannot accurately assess absolute fracture risk in an individual patient.
Our preliminary data suggest that measurement of individual fracture risk is feasible using a combination of bone structural, morphometric and biomechanical measurements.
Feasibility of Measurements of Bone Structure on Conventional Radiographs
Several methods have been described to examine trabecular structure using conventional projectional radiography. The earliest analysis techniques used microdensitometer-analog computer methods and Fourier transformation techniques. Simple texture analysis tools were then applied indicating that simple geometric patterns can be used to discriminate between the hips of normal controls and patients with osteoporotic fractures. Caligiuri et al. reported that fractal analysis of bone structure using standard 2D radiographs has a significantly greater area under the ROC curve than BMD measurements in differentiating normal patients and patients with osteoporotic compression fracture. Clearly, these preliminary studies provide a strong indication that measurements of bone structure in the hip represent a feasible approach for diagnosing osteoporosis and predicting fracture risk. Our technique for assessment of bone structure in the proximal femur using conventional radiographs is shown
The Need for a New Approach
BMD is correlated with in vitro fracture load and can estimate fracture risk in groups of subjects, but is incapable of providing individual fracture risk, specifically adjusted for local bone structure, morphometry, and biomechanical conditions in a given patient.
Combinations of risk factors account for only 20% to 40% of the variability in bone mass and have little value in estimating BMD.
HFPS automated hip radiographic imaging technology measures parameters similar to those used in bone histomorphometry. In general, it involves x-ray digitization, identification of regions of interests, trabecular extraction, background subtraction to obtain an image of trabecular structures, and binarization of those structures.
ImaTx HFPS is currently available in the US for investigational use only. Research organizations interested in using ImaTx HFPS are encouraged to contact ImaTx for more information.