Interfragmentary surface area as an index of comminution energy: proof of concept in a bone fracture surrogate

Fracture mechanics theory postulates a monotonic relationship between energy absorption and fracture surface generation. We hypothesized that this relationship was demonstrable to the point that, on a continuous scale, comminuted fractures created with disparate levels of energy delivery could be discriminated. Using a bone fracture surrogate in conjunction with digital image analysis of CT fracture data, we measured the surface area freed by controlled, discrete fracture simulations. Prior to these simulations, the reproducibility of the digital image analysis algorithm was validated with repeated measurements by two different operators. The parametric fracture series results showed a statistically significant difference in measured de novo surface area between four specimen groups, over a range of input energies from 1.4×1010–9.1×1010 J/m3 (or 12.5–80.2 J/specimen). The results of this study provide confirmation that comminution severity can indeed be measured on a continuous scale, based on energy absorption (another clinically meaningful index).