# Implantation of a Canine Total Ankle Replacement Prosthesis Using a Lateral Surgical Approach is Accurate and Leads to a Stable Joint

## TL;DR

This study shows that a lateral surgical approach can be used to implant a canine ankle replacement prosthesis with accurate joint orientation and rotational stability.

## Contribution

The study demonstrates the feasibility and accuracy of using a lateral approach for canine total ankle replacement.

## Key findings

- A lateral approach resulted in a properly oriented tarsocrural joint with slight angular laxity.
- The lateral approach provided rotational stability comparable to the medial approach.
- There were no significant differences in most measurements between the lateral and medial approaches.

## Abstract

This study aimed to determine if canine total ankle replacement (cTAR) can be performed using a lateral surgical approach by comparing implant orientation, limb orientation and tarsocrural stability after implantation using a lateral or medial approach.

Ten cadaveric limbs from five large-breed dogs were implanted with a cTAR prosthesis using a medial or a lateral approach. Caudocranial and mediolateral radiographs were obtained. Joint orientation, limb orientation, angular tarsocrural stability (varus and valgus laxity) and rotational tarsocrural stability (internal and external rotational laxity) were measured before and after implantation and compared. Polar gaps around cTAR components were measured.

Before implantation, mean valgus laxity was 1.8 degrees larger in limbs which were implanted with a cTAR prosthesis using a lateral approach than in limbs implanted using a medial approach. After a lateral approach, mean valgus laxity was 4.4 degrees larger (7.2 degrees) than before (2.8 degrees), and mean external rotational laxity was 5.4 degrees larger (10.7 degrees) than before (5.3 degrees). After a medial approach, mean external rotational laxity was 6.7 degrees larger (11.6 degrees) than before (4.9 degrees). The mean angular laxity was 6.0 degrees larger after a lateral approach (15.5 degrees) than a medial approach (9.5 degrees). Significant differences among other measurements collected after a lateral or medial approach were not identified.

A cTAR prosthesis can be implanted using a lateral approach and result in a properly oriented tarsocrural joint that is rotationally stable and has slight angular laxity.