The Function of the Short Lateral Collateral Ligaments of the Canine Tarsus: A Cadaveric Study

Abstract

ABSTRACT Information on the clinical behavior and treatment of cases with an isolated rupture of the short collateral ligaments of the canine tarsus is sparse and contradictory in the veterinary literature. Our objective was to evaluate the function of the short lateral collateral ligaments (SLCLs) of the tarsocrural joint in 90° flexion. Eight canine cadaveric limbs were tested for internal/external rotation and valgus/varus before and after transection of one or both SLCLs. In one group, the fibulocalcaneal ligament was transected first, followed by the fibulotalar. In the second group, the order of ligament transection was reversed. Angular changes between two k-wires were measured and compared. External rotation increased significantly after transection of one or both SLCLs (P = .009 and P < .0005), as did varus (P = .021 and P = .001). Lateral subluxation was only possible when both SLCLs were cut. Unlike the long lateral collateral ligament, which stabilizes against deviation toward medial, both SLCLs are major stabilizers against subluxation toward lateral. This important difference must be considered in clinical patients with isolated rupture of the SLCLs.