Accuracy of 3D Printed Subject-Specific Guides for Canine Total Hip Arthropasty

Introduction: Total hip arthroplasty (THA) is a well-accepted treatment for a variety of hip disorders in dogs; however, the surgery requires high precision. The purpose of this study was to assess the accuracy of femoral stem placement for THA using 3D printed guides. We hypothesized that the use of these guides would increase the accuracy of stem placement and decrease surgery time.

Materials and Methods: Five canine cadavers were used in this study to perform 10 THA. Patient-specific three-dimensional printed guides were created from computed tomography (CT) images. The femoral component of the THA was implanted in a traditional, ‘free-hand’ manner on one side, and using the guides on the contralateral side. Following implantation, CT scans were repeated, and final stem alignment was measured then compared with the digitally planned stem alignment.

Results: The mean difference between planned and postoperative stem alignment for guided surgery was 1.3±1.1 degrees for coronal stem angulation, 1.6±1.6 degrees for sagittal stem angulation and 5.7±6.5 degrees for axial stem angulation. The mean difference between planned and postoperative stem placement for the free-hand technique was 0.4±0.4 degrees for the coronal stem angulation, 2.6±1.1 degrees for the sagittal stem angulation and 10.7±5.9 degrees for axial stem angulation. Mean surgical procedure time for guided surgeries was 63% longer (42.4 ± 10.3 minutes) than free-hand surgeries (26.4 ± 6.0 minutes).

Discussion/Conclusion: Preliminary results suggest that use of custom fit patient specific 3D printed guides slightly increases accuracy of femoral stem placement but increases surgical time.

Acknowledgment: This study was funded by the Edward DeBartolo gift to the University of Florida.