A novel classification for aseptic femoral shaft nonunion after intramedullary nailing: a retrospective study

Although intramedullary nailing has been established as the gold standard for treating femoral shaft fractures, nonunion following intramedullary nailing remains a major concern for clinicians, severely affecting patients' walking ability and quality of life. Presently, there are certain controversies and deficiencies in nonunion classification and treatment. Herein, we propose a novel classification system for aseptic femoral shaft nonunion after intramedullary nailing based on X-ray-assessed nailing morphology and stability. Furthermore, we sought to explore the new classification's clinical significance and management implications.

This retrospective study involved the analysis of clinical data collected from 82 patients with aseptic bone nonunion after intramedullary nailing of femoral shaft fractures between 2010 and 2022. The patients were classified into four groups based on intramedullary nailing stability and bone defect existence, as revealed in X-ray images. The four classifications were as follows: Type I (intramedullary nailing is stable without bone defect), Type II (intramedullary nailing is stable with bone defect), Type III (intramedullary nailing is not stable without bone defect), and Type IV (intramedullary nailing is not stable with bone defect). Based on the novel classifications, we introduced individualized treatment methods. Type I patients underwent dynamization, and Type II patients received bone grafting and plate fixation. Type III patients underwent larger intramedullary nail exchange or plate fixation, and Type IV patients received larger intramedullary nail exchange and plate fixation with bone graft or double plate fixation with bone graft. Data on relevant indicators were collected.

All patients recovered well with no complications. The average surgery times for Types I-IV were 0.4 ± 0.1, 0.8 ± 0.2, 1.1 ± 0.4, and 1.6 ± 0.4 h, respectively. Furthermore, the mean blood loss volumes for Types I-IV were 23.4 ± 4.8, 53.3 ± 8.4, 56.3 ± 7.9, and 125.2 ± 10.8 ml, respectively. The average bone healing time of all 82 patients was 5.1 ± 1.5 months. On the other hand, the mean bone healing times for Types I-IV were 4.6 ± 1.1, 4.7 ± 1.1, 5.1 ± 1.5, and 5.7 ± 1.8 months, respectively. Furthermore, the LEFS scores for Types I-IV were 68.7 ± 3.5, 69.8 ± 3.1, 66.8 ± 3.8, and 68.6 ± 2.9 points, respectively. The mean surgery time and bleeding volume increased gradually from Types I to IV (p < 0.05) but with no significant difference between Types II and III. Moreover, there were no statistical differences in fracture healing times, LEFS scores, age, and nonunion durations across the four classifications.

The proposed novel classification system could achieve accurate diagnosis and guidance for clinical management of aseptic femoral shaft nonunion after intramedullary nailing. The corresponding individualized treatment approaches could improve prognostic outcomes and healing rates and alleviate postoperative complications.

Not applicable.