3D-printed titanium trail plate for repair of diaphyseal fracture of long bones in dogs.

The trail plate is a modular system consisting of a trail bar and synthesis modules made of stainless steel, originally developed for humans. This study aimed to evaluate the applicability and effectiveness of a modified trail plate for the treatment of long bone fractures in dogs. Initially, the trail plate was designed by using FEA to set the final model. Three trail plate sizes were designed according to corresponding locking screw diameters. The designs were created using computer-aided design software, and 3D models were produced from the commercial Ti-6Al-4 V powder via direct metal laser sintering (DMLS). The trail plate application included radius/ulna (n = 5), femur (n = 7), and tibia/fibula (n = 7). Radiographic bone healing occurred within 60 days in 100% of radius/ulna fractures, within 90 days in 70% of tibia/fibula fractures, and between 30 and 120 days postoperatively in femoral fractures. Radius/ulna fractures exhibited minimal callus formation, and all animals were free of lameness by 60 days. Femoral fractures showed mostly moderate callus formation, with lameness resolved in 57% of dogs by 60 days. In tibia/fibula fractures, callus ranged from minimal to abundant, with lameness resolved in six dogs by 60 days. Complications occurred in 36.8% of cases, primarily due to trail bar displacement of the module; only one case involved implant failure. In conclusion, this preliminary case series suggests that modified DMLS-manufactured titanium trail plate was clinically feasible for selected canine diaphyseal fractures. However, fixation-related complications indicate that further design optimization and controlled biomechanical studies are necessary before broader recommendation.