Infrapatellar vs. suprapatellar approach to obtain an optimal insertion angle for intramedullary nailing of tibial fractures

Background During intramedullary nailing of tibial fractures, the insertion angle of the nail is of great importance. When the nail impacts the posterior cortex due to a large insertion angle with a dorsal target course, higher insertion forces are needed, and the danger of iatrogenic fractures increases. Accordingly, the insertion direction should be as parallel as possible to the longitudinal axis of the tibia. We aimed to confirm the hypothesis that intramedullary nailing of tibial fractures can be performed with smaller insertion angles via a suprapatellar approach rather than infrapatellar approach. Methods In 19 human bodies of donors with intact tibiae, we performed intramedullary nailing by both a suprapatellar and an infrapatellar approach. The correct entry point was determined by fluoroscopy. Subsequently, the medullary canal was reamed up to a diameter of 10 mm, and a 9 mm polytetrafluorethylen tube was inserted instead of a tibia nail. The angle between the proximal aspect of the tube and the longitudinal axis of the tibia was measured using a computer-assisted surgery system. Results The angle between the proximal aspect of the inserted tube, simulating the tibial nail, and the longitudinal tibial axis was significantly larger when using the infrapatellar approach. Conclusions We achieved an insertion angle significantly more parallel to the longitudinal axis when using a suprapatellar approach for intramedullary nailing of tibial fractures. Thereby, both the risk of iatrogenic fracture of the posterior cortex and apex anterior angulation of the short proximal fragment can be reduced during intramedullary nailing of tibial fractures.