The energy of producing a fracture is considered one of the most important factors relating to injury severity, prognosis, and risk of complications, yet there has been no objective way to measure this important variable. The purpose of this study was to compare assessments of fracture severity made using new objective computed tomography (CT)-based methods versus the expert opinion of experienced orthopedic traumatologists. Fracture energy, fragment displacement, and soft tissue swelling were quantified in twenty tibial plafond fractures by analyzing injury CT scans. Three experienced orthopedic traumatologists then independently performed a rank order analysis of fracture severity, using plain radiographs. The concordance among the three clinicians ranged from 87% to 91%. Objective fracture severity measurements made with the CT algorithm agreed well with the clinical assessments (fracture energy concordance from 73% to 76%, fragment displacement from 82% to 89%, and soft tissue swelling from 61% to 65%). These are the first objective, CT-based measures of fracture severity. With further refinement, this conceptually novel method has the potential to serve as a valuable tool to provide objective measurement of fracture severity, allowing one to control for this previously confounding variable in large multicenter studies. ß 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res Keywords: fracture severity; intra-articular; post-traumatic arthritis Intra-articular fractures often portend secondary osteoarthritis (OA), chronic pain, and decreased joint function. The success of periarticular fracture management is dependent not only on how the fracture is treated but also on the fracture type and severity. 1-5 Decision making in treating complex articular injuries with comminution ( Fig. 1) requires that a surgeon assess the relative injury severity of a given case, and with this information, factor in the complexity of available treatment techniques, estimate prognosis, and weigh the risk for complications. Currently, no practical way exists to measure injury severity objectively. Existing methods have generally taken the form of fracture classification systems, based upon visual assessment of specified characteristics. Poor interobserver reliability is a persistent problem for these observer-based techniques, 20,22 with inaccurate identification and inconsistent interpretation of classification guidelines explaining much of the variability. With such poor reliability, comparisons among different studies is reduced to ''apples to oranges,'' hindering the compilation of a collective experience to guide patient care.The concept that ''the extent of bone, cartilage, and soft tissue damage is directly related to the energy imparted to these structures'' 6 is widely accepted among orthopedic traumatologists, and it provides a basis for objectively quantifying injury severity. To assess the mechanical energy involved in a fracture, a new computed tomography (CT)-based methodolog...