Objectives: To evaluate the accuracy of various CT based 3-dimensional print (3DP) technologies using morphometric measurements. Study Design: Experimental. Population: Cadaveric canine humeri and size-matched 3DP models. Methods: Fiduciary radiopaque markers were affixed to canine humeri of three different sizes (4 kg, 13 kg, 29 kg) at predetermined anatomical landmarks. 3DP models were created using one of three printers; desktop printers Form 3L and Ultimaker 5S, and industrial printer Objet Connex (n = 5/ group / printer). Marker based morphometric dimensions between cadavers and 3DP models were statistically compared using 2-factor repeated measures ANOVA followed by Tukey’s post-hoc test (P < 0.05). Results: Bone size and printer type both significantly affected 3DP accuracy, with size having the larger effect (P < 0.0001 and P < 0.02, respectively). Regardless of printing technology, model size was smaller than native bone in most cases. At the humeral condylar level, the best accuracy was seen in the medium-sized humerus with the Ultimaker printer ([0.09 mm], P< 0.03). Conversely, accuracy was reduced in the proximal humerus in all groups.
Conclusion: Desktop printers were overall more accurate than the industrial printer. Although significant differences were identified between models of different sizes, the sub-millimetric magnitude of these difference is unlikely to have a clinical impact. Clinical Significance: While pre-operative planning using 3DP models is becoming mainstream, accurate representation of the actual bone is critical. This study demonstrates that common desktop printers are suitable for this purpose.
