CORR Insights®: Are 3D-printed Models of Tibial Plateau Fractures a Useful Addition to Understanding Fractures for Junior Surgeons?

Where Are We Now?

In addition to anatomy, fracture classification systems are some of the earliest pieces of information that medical students and junior residents in orthopaedics learn. I keenly remember being a medical student, cramming in the minutiae of fracture classification systems knowing I would likely be quizzed on them. As I progressed in my training, I realized their value and relevance, and started to understand why some were used frequently and others were not even recognized by attending surgeons in orthopaedic trauma.

Classification systems should help us not only understand fractures but also guide treatment and provide prognostic information [1]. Although not every fracture is easy to understand, the commonly used classification systems are reliable; that is, they have relatively high levels of intra-observer and interobserver agreement (although often not as high as we would like). These are the ones that are the most useful in teaching and clinical practice. With advances in technology, additional tools for education and preoperative planning have become available. Can these be used to improve our understanding of fractures and make classifications more reliable and accurate?

Three-dimensional (3D) printed models are seeing wider use in orthopaedics because of their increasing availability and affordability [3, 5]. In my education, I encountered them increasingly for either preoperative planning or intraoperative assistance, or at times, simply because an attending physician could obtain them easily. I find them helpful for teaching trainees about fractures or bony abnormalities. For many surgeons, 3D-printed models likely remain a fascinating technology they do not know how to best use. Because it is important to control costs and minimize waste, studies have appropriately begun to evaluate whether 3D models provide specific and measurable benefits in orthopaedic applications, including education [4].

In this issue of Clinical Orthopaedics and Related Research, Huitema et al. [2] evaluated whether 3D-printed models could improve the interobserver agreement or accuracy of three different classification systems for tibial plateau fractures. They compared the use of 3D models with conventional imaging, which included radiographs as well as 2D and 3D CT. The participants in the study were grouped based on experience, and the results for trauma surgeons, senior surgical residents, and junior surgical residents were compared. The authors found the use of 3D-printed models only marginally helped to increase interobserver agreement among the junior residents, and this was not a clinically meaningful improvement. In the other groups, there was no difference, and none of the fracture classifications had more than moderate inter-observer agreement in any of the groups. This study shows that in the context of tibial plateau fractures, 3D-printed models may not be helpful for education and/or preoperative planning. It also highlights that the currently available classification systems may lead to frequent misclassifications of tibial plateau fractures.

Where Do We Need To Go?

An understandable concern of Huitema et al. [2] is that the lower interobserver agreement of the tibial plateau classification systems could lead to fracture misclassification and possibly harm to patients. If this is true, it raises the question of whether classification systems are helpful. And if so, what are they useful for? Diagnosis? Treatment? Prognosis? Each classification system is unique, and each has its strengths and weaknesses [6]. Almost invariably, the systems that have stood the test of time and remain commonly used are superior, but in what way? Is the utility of specific classification systems being taught to trainees in a conceptual manner so they can truly learn their value rather than just commit the information to rote memory? And to address the authors’ concern, can misclassification of fractures lead to mistreatment of patients and subsequent harm? Certainly, if a junior resident were unable to tell the difference between a lower-energy versus a higher-energy tibial plateau fracture and were to miss an associated compartment syndrome or vascular injury [7], this could lead to patient harm. But is this common? An attending surgeon could also misclassify a tibial plateau fracture and choose an inappropriate surgical approach to fix a fracture. These scenarios may be unlikely, but it is worth studying how frequently they occur. And does fracture misclassification point to a deficiency in the classification system or simply highlight the great variety in the types of fractures that can occur?

Regarding 3D-printed models, the authors’ results clearly show that these models are not necessary for all tibial plateau fractures. But with advances in technology and reductions in price for obtaining 3D CT or 3D models, in which fractures should such technologies be used? In a healthcare environment that has historically leaned toward the “spare no expense” mentality, cost-effectiveness and avoiding waste are important issues. The results may have different applications for surgeons practicing in different settings. 3D-printed models may provide no additional benefit in improving the classification or understanding of a fracture for a seasoned surgeon, but if they are found to be helpful for students and trainees to obtain a more-tangible understanding of a fracture, might they be worth obtaining in the academic setting, where attendings surgeons are educating the future generation of orthopaedists?

How Do We Get There?

We should never cease trying to improve, so it is possible to build upon existing classification systems for tibial plateau and other fractures or develop better systems. But in the meantime, understanding the exact benefits and drawbacks of the existing systems should be the goal, not only for clinical practice but also for education. Consensus panels could determine what classification systems should be used for what purpose, and which systems should be taught to trainees of various levels. Survey studies of trainees and attending surgeons worldwide would likely highlight that various systems are used more frequently in certain parts of the world. This should not be surprising, but the results of such studies could help lead to a more consistent language worldwide in the educational, research, and clinical settings. The strengths, and perhaps more importantly, the limitations of certain classification systems should be evaluated, and this information should be shared readily with trainees. A large-scale analysis of attending and resident surgeons’ documentation could identify the frequency with which fractures are misclassified and determine whether incorrect treatments are pursued or whether outcomes are affected by these misclassifications. Although inconsistencies in documentation or geographic differences in classification use may make such a study difficult (because not everyone documents the specific Schatzker classification of a tibial plateau fracture, for example), specific characteristics of fractures are almost always described. These descriptions could be analyzed and evaluated for accuracy, and subsequent treatments could be evaluated for appropriateness based on the standard of care.

Time will tell whether the use of 3D-printed models will continue to expand in orthopaedics. When the novelty wears off, surgeons treating fractures will likely only use these models if they help them in their clinical practice or if they assist in teaching concepts to trainees. Clinical outcomes may not be directly affected by the use of 3D-printed models, but studies could evaluate whether surgeons feel more or less prepared for procedures, with or without the use of models. Increased preparation or a feeling of confidence by surgeons could certainly help operations go more smoothly, so there may also be an indirect benefit of 3D-printed models that could be difficult to identify in a research study. For trainees, if 3D-printed models could be created that allowed them to reconstruct complex periarticular fractures using plates and screws (for example, a more-complex version of the generic Sawbones fracture models), this could be beneficial in preparing for surgery. Studies could also compare trainees’ surgical preparation and knowledge retention with or without the use of 3D-printed models. The costs and benefits of 3D-printed models need to be carefully considered in each clinical and educational environment, because surgeons in different settings have unique priorities and will likely reach different conclusions.