The Accuracy of 3D Printed Carpal Bones Generated from Cadaveric Specimens

Computer assisted three-dimensional (3D) printing of anatomic models using advanced imaging haswide applications within orthopaedics. The purpose of this study is to evaluate the 3D printing accuracy of carpalbones. Seven cadaveric wrists underwent CT scanning, after which select carpal bones (scaphoid, capitate, lunate,and trapezium) were dissected in toto. Dimensions including length, circumference, and volume were measured directlyfrom the cadaver bones. The CT images were converted into 3D printable stereolithography (STL) files. The STL fileswere converted into solid prints using a commercially available 3D printer. The 3D printed models’ dimensions weremeasured and compared to those of the cadaver bones. A paired t-test was performed to determine if a statisticallysignificant difference existed between the mean measurements of the cadavers and 3D printed models. The intraclasscorrelation coefficients (ICC) between the two groups were calculated to measure the degree of agreement. On average, the length and circumference of the 3D printed models were within 2.3 mm and 2.2 mm,respectively, of the cadaveric bones. There was a larger discrepancy in the volume measured, which on average waswithin 0.65 cc (15.9%) of the cadaveric bones. These differences were not statistically significant (P > 0.05). Therewas strong agreement between all measurements except the capitate’s length and lunate’s volume. 3D printing can add value to patient care and improve outcomes. This study demonstrates that 3D printingcan both accurately and reproducibly fabricate boney models that closely resemble the corresponding cadaveric anatomy.Level of evidence: V