The use of three-dimensional models in tibial plateau fractures

Background: To compare three-dimensional (3D) printed models with 3D computed tomography (CT) images in terms of the reliability of the classification of tibial plateau fractures using the Hohl and Moore and the Schatzker classification systems, and whether there was any influence on surgical management. Method: The sample comprised the 20 CT scans of patients with tibial plateau fractures available in the radiology archive of Dr George Mukhari Academic Hospital (Ga-Rankuwa). Standardised illustrated guides to the Schatzker and the Hohl and Moore classification systems were used by six observers of varying orthopaedic experience. They completed questionnaires individually in three different sessions. In session one the observers had access to the 3D CT images only. On average two to five days later, in session two the observers assessed only the 3D models. In the third session, another two-to-five days later, the observers assessed the 3D CT images while handling and inspecting the corresponding 3D model. Results: The inter-observer reliability of the Schatzker system (moderate reliability) was superior to the Hohl and Moore system (fair reliability) when comparing the assessment using the images and models separately. When all observations were combined, there was no difference between the systems. For the six possible surgical management options given to the observers, there was an overall difference in agreement based on assessing only the CT images compared with assessing only the models, of 19% (23 of the possible 120 procedures). Of these 23 differing procedures, 15 were more invasive. The 3D models were considered superior to 3D CT imaging in terms of spatial awareness and the observers’ ability to assess intra-articular fracture patterns. The models were assessed as being superior to the imaging when considering the ability to estimate the quantity of bone graft required. Conclusion: Although the inter-rater reliability of classification was not significantly improved, there were several advantages to using the 3D-printed models both separately from the CT images and together with the images. The effect of 3D models on patient outcome remains untested. The clinical impact of the use of 3D models (including cost, manufacturing time and radiation exposure) should be weighed against the potential benefits. Level of evidence: Level 4