Intramedullary interlocking nail stabilisation of 21 humeral fractures in 19 dogs and one cat.

ABSTRACT

OBJECTIVE: To assess the suitability of the intramedullary interlocking nail to stabilise humeral diaphyseal fractures in dogs and cats. METHOD: This multi-centre study retrospectively examined medical records, between June 1994 and May 2001, of 19 dogs and one cat, in which a total of 21 humeral fractures were stabilised with intramedullary interlocking nails. RESULTS: Animals ranged in body-weight from 4 to 97 kg. Eighteen (86%) of the fractures were comminuted. Adjunctive stabilisation was used in twelve (57%) fractures and bone grafts in nine (43%) fractures. A rapid return of function was noted in the majority of animals, with 14 (67%) having good or excellent function within four days of surgery. In two fractures the repair collapsed when a single proximal transcortical screw was placed cranial to the tricipital line of the humerus. This suggests that if a single transcortical screw is placed proximally the screw should be distal or caudal to the tricipital line in order to engage sufficient cortical bone. Eighteen (86%) of the fractures healed when stabilised with intramedullary interlocking nails. Three fractures did not heal. One was in a dog where a pathological fracture was temporarily stabilised with an intramedullary interlocking nail, one in a dog that died of an abdominal crisis three weeks after surgery and one in a dog in which fracture stabilisation collapsed due to incorrect implant selection. CONCLUSION: Intramedullary interlocking nails are well suited to the stabilisation of humeral diaphyseal fractures in dogs and cats.