Accuracy of three-dimensional printed patient-specific drill guides for treatment of canine humeral intracondylar fissure

Authors: 
Easter TG, Bilmont A, Pink J, Oxley B.
Vet Surg. 2019 Nov 12. doi: 10.1111/vsu.13346.

OBJECTIVE: To determine the accuracy of three-dimensional printed patient-specific drill guides (3D-PDG) as treatment of humeral intracondylar fissures (HIF) in dogs.

STUDY DESIGN: Retrospective consecutive case series.

ANIMALS: Client-owned dogs with HIF treated with a 5-mm transcondylar screw (TCS) placed from medial to lateral with a 3D-PDG.

METHODS: The proposed TCS entry point and trajectory were planned using computed tomography (CT) data and computer-aided design software (CAD), and a 3D-PDG was produced. During surgery the 3D-PDG was used to drill the pilot hole from medial to lateral; the guide was then removed, the pilot hole was overdrilled, and a 5-mm TCS was placed. Postoperative CT data were imported into CAD software, and the entry points, exit points, and trajectories were compared between the planned and actual screw locations.

RESULTS: Sixteen elbows from 11 dogs were included. Mean (SD) entry point translation was 1.3 mm (0.64), with all screws entering cranial to the proposed location. Mean maximum screw angulation was 5.2° (2.10°), with most screws directed caudodistal to the desired trajectory. Mean (SD) exit point translation was 1.8 mm (0.89) from the planned location. There was no intra-articular screw placement.

CONCLUSION: Use of a 3D-PDG permitted accurate placement of a mediolateral 5-mm locking TCS within the humeral condyle.

CLINICAL SIGNIFICANCE: Three-dimensional printed patient-specific drill guides should be considered as accurate and consistent for placing TCS for treatment of HIF in dogs.

Small animal: