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

Abstract

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Clinical trial number: Not applicable.

Keywords: Aseptic femoral shaft nonunion; Femoral shaft fracture; Intramedullary nailing; Nonunion classification.

Fig. 1

Diagram depicting aseptic bone nonunion following intramedullary nailing of the femoral shaft fracture and treatment modes of each type. I: Type I (Ia)-Intramedullary nailing is stable without bone defect and the diameter of intramedullary nailing is not significantly smaller than that of the medullary isthmus; and (Ib)-Removal of the locking screws. II: Type II (IIa)-Combined with a localized bone defect based on Type I; and (IIb)-Bone graft and plate fixation. III: Type III (IIIa)-The diameter of the intramedullary nail is significantly smaller than that of the medullary isthmus, and there is callus formation at the fracture site without a bone defect; (IIIb)-Replacing the larger intramedullary nail; and (IIIc)-Plate fixation without replacing the intramedullary nail. IV: Type IV (IVa)-Combined with bone defect based on Type III; (IVb)-Replacing the larger intramedullary nail with one that has a diameter comparable to that of the medullary isthmus, callus removal at the bone defect site, bone grafting and plate fixation; (IVc)-Removal of the intramedullary nail, bone grafting and double plate fixation

Fig. 2

A 35-year-old man had a motorcycle accident resulting in a femoral shaft fracture and sustained Type I nonunion for 1 year. Dynamization was performed, and a callus formed one month later

Fig. 3

A 30-year-old man sustained Type II nonunion for 20 months after intramedullary nailing. The fracture started to gradually heal three months after bone grafting and plate fixation

Fig. 4

A 48-year-old man sustained Type III nonunion for 14 months and was implanted with an intramedullary nail with a diameter significantly smaller than that of the medullary cavity. Plate fixation was performed, and the fracture healed three months post-surgery

Fig. 5

A 57-year-old man sustained Type IV nonunion for 15 months, which included a local bone defect and relatively narrow intramedullary nail diameter compared to medullary diameter. Larger intramedullary nail replacement, bone grafting, and plate fixation were performed, and a callus formed two months postoperatively