Use of a Temporary Calcaneotibial Screw to Stabilize the Talocrural Joint in Dogs

Introduction: A temporary calcaneotibial screw (CTS) can be used to support the talocrural joint in dogs following surgery for fracture/luxation/Achilles’ rupture. However, evidence-based recommendations on the angle of insertion of a CTS are not available.

Materials and Methods: The paired hind limbs of 12 canine cadavers were randomly assigned to receive either a CTS placed perpendicular to the calcaneus (calcaneus group), or a CTS placed perpendicular to the tibia (tibia group), with the tarsus in full extension. Biomechanical testing was performed in compressive loading using an Instrom 1195: 10 mm/sec. The load to failure was compared using a paired t-test. Four working dogs (two collies and two Labradors) with instability of the talocrural joint due to ligamentous injury (four) and/or malleolar fractures (two) were treated with a CTS and a lateral splint (two) or bivalved cast (two) to support the primary repair/prosthetic ligament for 6 weeks.

Results: A CTS placed perpendicular to the calcaneus had a significantly higher load to failure than a CTS placed perpendicular to the tibia. Screws placed perpendicular to the tibia were subjected to greater bending leading to lower failure loads than screws perpendicular to the calcaneus that would need to fail by pull out. The four clinical cases had a successful outcome and returned to activity.

Discussion/Conclusion: A temporary CTS should be inserted perpendicular to the calcaneus. In a small case series, a temporary CTS was used to successfully protect surgical repairs required for instability of the tarsocrural joint.

Acknowledgment: Funded by the Massey University Working Dog Centre, NZ. No proprietary interests.

No conflict of interest has been declared by the author(s).