Effect of a calcaneo-tibial screw on medial and lateral stability of the canine tarsocrural joint ex vivo.

Abstract

To evaluate the use of a temporary calcaneo-tibial screw for stabilization of the tarsocrural joint in dogs with surgically treated collateral ligament injury. The degree of varus and valgus laxity of the tarsocrural joint in various states of injury and stabilization was measured in paired cadaveric limbs of Greyhound dogs. The angle of varus or valgus laxity was calculated following simulated collateral ligament injury (long collateral ligament only, long and short collateral ligaments, and bilateral long and short collateral ligaments) and stabilization with a calcaneo-tibial screw. The joint was significantly more stable after placement of a calcaneo-tibial screw compared to limbs with any combination of injured collateral ligaments. There was not a significant difference between stability of the intact limb compared to the injured limb with calcaneo-tibial screw fixation. Calcaneo-tibial screw fixation appears to be an adequate method of stabilizing the tarsocrural joint following collateral ligament injury, and warrants clinical evaluation as a less expensive alternative to external skeletal fixation application. It is likely that this method would need to be supplemented with a cranial half cast to prevent screw failure during weight bearing.