Computer-based periaxial rotation measurement for aligning fractured femur fragments: Method and preliminary results

Abstract

We describe a new computer-based method for periaxial rotation measurement of healthy and fractured femurs during closed femoral fracture reduction surgery from CT. The method provides a comparative quantitative measure to align the distal and proximal femur fragments based on periaxial rotation. We define periaxial rotation in terms of patient-specific bone features and describe an algorithm for automatically extracting these features from the CT. The algorthm extracts condyle landmarks and neck axis of the healthy bone, determines its periaxial rotation, and extrapolates this data, assuming mirror symmetry between the healthy and the fractured bone, to measure periaxial rotation between the fractured fragments. Unlike existing techniques, our method requires minimal user intervention. We applied the method to a patient data set and simulated a reduction based on the anteversion measurements with satisfactory results.