Development of an expedited objective fracture severity assessment methodology

Post-traumatic osteoarthritis (PTOA) is a debilitating disorder resulting from trauma to an articulating joint. The condition imposes a significant physical and emotional burden on an individual, with substantial financial implications, as well. The severity of the joint trauma has been shown to correlate highly with the risk of subsequent PTOA development, so treating surgeons have adopted fracture severity assessment methods to aid in their treatment decision-making. However, current systems for classifying the severity of the trauma are highly subjective and have poor reproducibility. This makes it difficult to differentiate PTOA development attributable to the initial injury from that potentially influenced by the chosen treatment. The most common situation in which this problem arises is for an articular fracture, treatment of which involves decisions related to trying to restore the fragmented articular surface.

To address these limitations in assessing fracture severity, a CT-based severity metric was previously developed, with the goal of providing an objective, quantifiable measure of initial injury severity. Utilizing fracture mechanics theory, the CT-based severity metric used measures of interfragmentary surface area to infer the amount of energy absorbed during fracture, the amount of comminution in the resulting fracture, and the level of dispersion and displacement of the fracture fragments. Combining these components into a single overall severity score produced a reliable metric for objective assessment of fracture severity. However, this assessment approach did present some practical limitations, which precluded its use in routine clinical care. The greatest limitation was the time required to obtain a severity score. At roughly 8 hours, it was too much time before a surgeon could get a score to assist in treatment planning. Another major challenge in using the severity metric was that its acquisition depended upon the contralateral intact limb being included in the CT scan, for taring purposes. Even though using the intact contralateral would be ideal, obtaining this limb in the CT scan for each patient would be a difficult challenge impeding the implementation of the expedited metric in the routine clinical setting. To address these limitations, an expedited approach for severity assessment has been developed. The expedited approach builds upon the prior fracture mechanics methods, but it utilizes a textural image analysis of CT images from the fractured bone, in lieu of measurement of interfragmentary surface area. The focus of this thesis is the implementation and development of an expedited fracture severity metric that can be used clinically. Such a metric would aid in showing the relative benefits of certain surgical treatments as well as in guiding the surgeon in developing a treatment plan for their patients.