Comparison of three-dimensional printed patient-specific guides versus freehand approach for radial osteotomies in normal dogs: Ex vivo model

ObjectiveTo compare the accuracy of three-dimensional (3D) printed patient-specific guide (PSG) with a freehand (FH) approach for radial osteotomies in ex vivo normal dogs. Study designExperimental study. AnimalsTwenty four ex vivo thoracic limb pairs from normal beagle dogs. MethodsComputed tomography (CT) images were collected preoperatively and postoperatively. Three osteotomies tested (n = 8/group) were: (1) uniplanar 30 degrees frontal plane wedge ostectomy, (2) oblique plane (30 degrees frontal, 15 degrees sagittal) wedge ostectomy, and (3) single oblique plane osteotomy (SOO, 30 degrees frontal, 15 degrees sagittal, and 30 degrees external). Limb pairs were randomized to a 3D PSG or FH approach. The resultant osteotomies were compared with virtual target osteotomies by surface shape-matching postoperative to the preoperative radii. ResultsThe mean +/- standard deviation osteotomy angle deviation for all 3D PSG osteotomies (2.8 +/- 2.8 degrees, range 0.11-14.1 degrees) was less than for the FH osteotomies (6.4 +/- 6.0 degrees, range 0.03-29.7 degrees). No differences were found for osteotomy location in any group. In total, 84% of 3D PSG osteotomies were within 5 degrees deviance from the target compared to 50% of freehand osteotomies. ConclusionThree-dimensional PSG improved FH accuracy of osteotomy angle in select planes and the most complex osteotomy orientation in a normal ex vivo radial model. Clinical significanceThree-dimensional PSGs provided more consistent accuracy, which was most notable in complex radial osteotomies. Future work is needed to investigate guided osteotomies in dogs with antebrachial bone deformities.