To explore the relationship between smoking cessation and nonunion in femoral shaft fracture patients with long-term smoking.

Retrospective analysis of patients with femoral shaft fractures treated or reviewed in People′s Hospital of Fenxian District in Shanghai from 2016 to 2017. Inclusion criteria: unilateral femoral shaft fractures treated with intramedullary nails, smoking history≥5 years; exclusion criteria: open fractures, long-term bedridden, severe osteoporosis, fractures with other parts, infectious nonunion. According to whether the patient smoked before injury or quit smoking after injury, the patients who had no smoking history before injury were included in the non-smoking group, the patients who successfully quit smoking after injury were included in the smoking cessation group, and patients who did not quit smoking after injury were included in the non-quit smoking group. The time to achieve clinical healing of fractures was recorded in the three groups. Chi-square test was used to identify the differences in the incidence of nonunion in the three groups of patients. The Kaplan-Meier method was used to estimate and compare the median time to clinical healing of fractures.

Bone nonunion occurred in 12.5% (four cases) of the non-smoking group, 20.4% (11 cases) of the smoking cessation group, and 52.9% (nine cases) of the non-quit smoking group, the difference was statistically significant (χ²=10.705, P<0.05). Pairwise comparison showed that the incidence of nonunion in the non-quit smoking group was significantly higher than in the non-smoking group (χ²=9.315, P <0.0167) and the smoking cessation group (χ²=6.779, P <0.0167). The median time to fracture healing in the three groups was estimated to be 15.1 weeks [95% confidence interval (CI) (14.9, 15.3) weeks], 22.0 weeks [95% CI (21.7, 22.4) weeks], and 51.1 weeks. There were differences in the timing of fracture healing among the three groups of patients (P<0.05).

Long-term smoking of patients with femoral shaft fractures who can quit smoking in time after injury will reduce the incidence of nonunion, but the clinical healing time of fractures is slightly longer than that of non-smokers.