Intramedullary Interlocking Nail Fixation in Dogs and Cats: Biomechanics and Instrumentation*

of diaphyseal long bone fractures. Interlocking nails have transverse cannulations that accommodate transcortical screws, allowing surgeons to firmly fix the rod within the medullary canal, thereby effectively neutralizing bending, rotational, and axial forces that act on fractures. Interlocking nails have become increasingly To counter axial and rotational forces, intramedullary nails were developed with prefabricated holes to accommodate transcortical screws, which are inserted proximal and distal to the fracture line and securely locked the nail into position within the bone. Human orthopedic surgeons routinely use intraoperative fluoroscopy to facilitate fracture reduction, nail insertion, and accurate placement of locking screws; however, restricted access to fluoroscopy has delayed the application of interlocking nails in veterinary medicine. Intramedullary interlocking nail systems that circumvent the need for intraoperative fluoroscopy have recently been developed, allowing their use in veterinary surgery. Interlocking nails have several advantageous biomechanical characteristics compared with intramedullary pinning, external skeletal fixation, and bone plating.This article compares the biomechanics of interlocking nails with other commonly used fracture fixation modalities in veterinary medicine and describes the instrumentation and implants in the Dueland interlocking nail system. ABSTRACT: