Clinical and Radiological Evaluation of Tie-in Osteosynthesis with Intramedullary Threaded Pin in Diaphyseal Humeral, Tibial, and Femoral Fractures in Dogs

This study aimed to perform the "tie-in" osteosynthesis technique using an intramedullary threaded pin for the treatment of diaphyseal humeral, tibial, and femoral fractures in dogs, thus minimizing rotational movements and strengthening stabilization, particularly in distal diaphyseal fractures. The study included 16 fracture cases involving 14 dogs of various breeds and sexes, aged 3-12 months, and diagnosed with diaphyseal humeral, tibial, and femoral fractures. Depending on the size of the case, circle divide 2-4 mm-threaded Steinmann pins were preferred for use in intramedullary pinning and circle divide 2-4 mm-threadless Steinmann pins were placed transversal for fixation. Acrylic, rod, or fiberglass plaster was used to attach the inserted pins. Fusion was formed in all except two cases. Consequently, the animals could use their relevant extremities without issues during the first 3 days following the operation, but from day 3 until day 15, the animals were reluctant to use their relevant extremities. After day 15, the animals could use their extremities without difficulty. The external fixator components used in fracture fixation were entirely removed after 5-7 (mean 6) weeks. In the functional evaluation, the conditions were very good in nine cases, good in four, moderate in one, and poor in two. The results reveal that the use of threaded pins in intramedullary pinning, the first step of the tie-in method, provides good stabilization in fracture treatment, especially in distal diaphyseal fractures.