Recognition of the pattern of complex fractures of the elbow using 3D-printed models

Aims This study aimed to answer the following questions: do 3D-printed models lead to a more accurate recognition of the pattern of complex fractures of the elbow?; do 3D-printed models lead to a more reliable recognition of the pattern of these injuries?; and do junior surgeons benefit more from 3D-printed models than senior surgeons?Methods A total of 15 orthopaedic trauma surgeons (seven juniors, eight seniors) evaluated 20 com-plex elbow fractures for their overall pattern (i.e. varus posterior medial rotational injury, terrible triad injury, radial head fracture with posterolateral dislocation, anterior (trans- )olec-ranon fracture-dislocation, posterior (trans-)olecranon fracture-dislocation) and their specific characteristics. First, fractures were assessed based on radiographs and 2D and 3D CT scans; and in a subsequent round, one month later, with additional 3D-printed models. Diagnostic accuracy (acc) and inter-surgeon reliability (& kappa;) were determined for each assessment.Results Accuracy significantly improved with 3D-printed models for the whole group on pattern recognition (acc2D/3D = 0.62 vs acc3Dprint= 0.69; & UDelta;acc = 0.07 (95% confidence interval (CI) 0.00 to 0.14); p = 0.025). A significant improvement was also seen in reliability for pattern recog- nition with the additional 3D-printed models (& kappa;2D/3D = 0.41 (moderate) vs & kappa;3Dprint = 0.59 (mod-erate); & UDelta;& kappa; = 0.18 (95% CI 0.14 to 0.22); p & LE; 0.001). Accuracy was comparable between junior and senior surgeons with the 3D-printed model (accjunior = 0.70 vs accsenior = 0.68; & UDelta;acc =-0.02 (95% CI-0.17 to 0.13); p = 0.904). Reliability was also comparable between junior and senior surgeons without the 3D-printed model (& kappa;junior = 0.39 (fair) vs & kappa;senior = 0.43 (moderate); & UDelta;& kappa; = 0.03 (95% CI-0.03 to 0.10); p = 0.318). However, junior surgeons showed greater improve- ment regarding reliability than seniors with 3D-printed models (& kappa;junior = 0.65 (substantial) vs & kappa;senior = 0.54 (moderate); & UDelta;& kappa; = 0.11 (95% CI 0.04 to 0.18); p = 0.002).Conclusion The use of 3D-printed models significantly improved the accuracy and reliability of recog- nizing the pattern of complex fractures of the elbow. However, the current long printing time and non-reusable materials could limit the usefulness of 3D-printed models in clinical practice. They could be suitable as a reusable tool for teaching residents.