Effect of fracture level on the residual fracture gap during tibial intramedullary nailing for tibial shaft fractures

Background: The development of fracture gap during intramedullary nailing in tibial fractures is associated with poor fracture fragment contact and increased time to union and complications. This study aimed to evaluate the effect of the fracture level in the development of fracture gap and the effect of the fracture gap on pain, radiologic and functional outcomes, and complication rate. Methods: A total of 45 patients who underwent reamed intramedullary nailing due to closed transverse or short oblique tibial shaft fractures were divided into the proximal fracture group and distal fracture group. The correlations between visual analog scale (VAS) score, modified radiograph union score for tibias (RUST), and postoperative 1-year lower extremity functional scale scores, fracture level, gap amount, and time to union were evaluated. Results: The mean fracture gap amounts in the immediate postoperative anteroposterior and lateral radiographs were 5.6 ± 1.7 and 6.0 ± 1.7 mm in proximal fractures and 0.3 ± 2.4 mm and 0.4 ± 2.3 mm in distal fractures, respectively (p < 0.001 and p < 0.001, respectively). The mean time to union was 21.9 ± 2.9 weeks in the proximal fracture group and 16.7 ± 2.4 weeks in the distal fracture group (p < 0.000). The fracture gap amount significantly correlated with the level of fracture (r = 0.811, p < 0.001). Conclusion: Tibial shaft fractures proximal to the isthmus level tend to develop significantly larger fracture gap than distal fractures. It is associated with increased time to union and radiographic union scores as well as slightly higher complication and reoperation rates. Level of Evidence Level III, prognostic