Factors Affecting Posterior Angulation in Retrograde Intramedullary Nailing for Distal Femoral Fractures

Financial support: None. Conflict of interests: None. Purpose: To analyze the factors that cause a posterior angulatory deformity in the retrograde intramedullary nailing of distal femoral fractures. Materials and Methods: Fifty-five patients with distal femur fractures who were treated with retrograde intramedullary nailing were enrolled in this study. They were followed-up for at least one year postoperatively. The posterior angulatory deformity was evaluated according to the fracture location, pattern, and insertion point and the insertion point was compared with the ideal point derived from the radiographs of 100 normal adults. The correlation between the posterior angulation and the entry point of the nail was analyzed. Results: The posterior angulation was similar in terms of the fracture location; a meaningful difference was noted among the fracture patterns (p=0.047). The posterior angulation was significantly greater when the entry point was located more posteriorly, accepting a malreduced state (p=0.012). Conclusion: Posterior angulation was smaller in the transverse fracture and the posterior location of the entry point from the apex of the Blumensaat’s line increased the posterior angulation.