Hayede Jalilpour - Department of Clinical Sciences, School of Veterinary Medicine, Shiraz university, Shiraz, Iran.
Abdolhamid Meimandi-Parizi - Department of Clinical Sciences, School of Veterinary Medicine, Shiraz university, Shiraz, Iran.
Azizollah Khodakaram-Tafti - Department of Pathobiology, School of Veterinary Medicine, Shiraz university, Shiraz, Iran.
Mohamad Saeed Ahrari-Khafi - Department of Clinical Sciences, School of Veterinary Medicine, Shiraz university, Shiraz, Iran.
Seyedreza Hashemi - Department of Clinical Sciences, School of Veterinary Medicine, Shiraz university, Shiraz, Iran.

Objective- Tibiotarsal bone is the most commonly fractured long bone in small companion birds. The treatment options are basically limited to tape splinting the leg due to anatomical limitations. The goal of this study was to investigate intramedullary pinning (IM pin) as an alternative treatment option.Design- Experimental studyAnimals- Thirty mature budgerigars with an average weight of ۳۰ g. Procedures- The birds underwent mid shaft tibiotarsus osteotomy and the fractures were managed by tape splinting or IM pining in each group. The IM pins and splints were removed at ۲۱st day after surgery. Radiology was performed at ۰, ۷, ۱۴, ۲۱ and ۲۸ days after surgery. Histopathological and biomechanical evaluations were performed on specimens by day ۲۸. Stability on palpation, lameness scores and mortality rate were recorded.Results- Radiography showed perfect bone healing in the IM pin group versus the presence of malunion and deformity in the splint group. Histopathology demonstrated a more advanced bone healing in the IM pin group, characterized by the dominance of new bone trabeculae and new cortex formation with very little fibrous tissue. Biomechanical tests revealed significantly higher yield load, ultimate load, stiffness, and absorbed energy in the IM pin group (p <۰.۰۵). Lameness scores were significantly better in the tape splint group (p <۰.۰۵) and the mortality rate was ۰ in the splint group versus ۳۳% in the IM pin group.Conclusion and Clinical relevance- Although IM pinning showed a more advanced level of bone healing radiographically, histopathologically, and biomechanically, the higher mortality rate and higher lameness scores make it a less desirable choice for pet birds. IM pinning technique did not prove to be as safe as the tape splintage technique. Tape splinting remains the gold standard in managing the fractures of the tibiotarsal bone in budgerigars as it offers low risk and high acceptability.

Budgerigar, Fracture Healing, IM pin, Splint, tibiotarsus