Smoking Increases the Risk of Complications in Bone Fracture Healing

Postoperative wound infections and bone healing complications after nonpathological fracture surgery are higher in smokers vs nonsmokers. These findings, from a systematic review and meta-analysis, were published in EClinicalMedicine.

Several medical publication databases were searched through August 2021 for the effect of smoking or drinking alcohol on infections and nonunion rates healing following surgery for nonpathological fractures. A total of 122 studies were included in the qualitative analysis, with 71 studies eligible for the quantitative synthesis.

The majority of studies were conducted in North America (37%), Europe (35%), Asia (27%), and Africa (1%). About 34% of the studies had ≤100 patients, and 29% had between 101 and 300 patients.

Nonunion rates were higher among smokers compared with nonsmokers (odds ratio [OR], 2.50; 95% CI, 1.73-3.61; P <.0001; I²=64%). No effect was observed for delayed union rates in smokers vs nonsmokers (OR, 1.35; 95% CI, 0.51-3.59; P =.55; I²=0%). Time to union did not differ on the basis of smoking (mean difference [MD], 0.52 weeks, 95% CI, -1.29 to 2.33; P =.57; I²=0%).

Patients who smoked had an increased risk for deep surgical site infection (OR, 2.04; 95% CI, 1.68-2.48; P <.0001; I²=0%) and undefined surgical site infection (OR, 3.11; 95% CI, 2.09-4.63; P <.0001; I²= 66%) vs nonsmokers. No relationship was observed between smoking and superficial surgical site infection (OR, 1.27; 95% CI, 0.73-2.21; P =.39; I²= 0%) or normal union (OR, 1.60; 95% CI, 0.78-3.26; P =.20; I²=0%).

Cessation from smoking for ≥4 weeks (OR, 0.37; 95% CI, 0.16-0.89; P =.03; I2=49%) or ≥6 weeks (OR, 0.22; 95% CI, 0.06-0.83; P =.03; I2=47%) prior to surgery decreased postsurgical wound infection rates compared with continuous smokers. However, no significant difference was found when preoperative smoking cessation ≥4 weeks (OR, 1.19; 95% CI, 0.43-3.32; P =.74; I2=79%) was compared with the nonsmoking group.  An impaired wound healing rate was increased in smoking cessation ≥4 weeks before surgery (OR, 1.93; 95% CI, 1.17-3.20; P =.01; I2=0%) compared with nonsmokers. No significant difference was found ≥4-weeks smoking cessation before surgery for decreasing hematoma risk compared with continuous smoking (OR, 0.36; 95% CI, 0.11-1.20; P =.10; I2=0%).

Alcohol consumption did not significantly affect nonunion of fractures (OR, 0.97; 95% CI, 0.40-2.38; P =.95), but time to union was longer among alcohol drinkers (MD, 12.85 weeks; 95% CI, 1.23-24.47; P =.03).

No statistically significant difference between alcohol drinkers and nondrinkers was found in deep surgical site infection rates (OR, 1.02; 95% CI, 0.64-1.62; P =.94; I²=0%) nor was undefined surgical site infection rates (OR, 1.28; 95% CI, 0.81-2.03; P =.29; I²=60%). Investigators noted that a meta-analysis on malunion in these groups could not be conducted due to insufficient data.

This analysis may have been limited as not all studies adjusted for confounders.

“Smoking is associated with higher rates of nonunion and deep surgical site infection after nonpathological fracture treatment,” the study authors concluded. “Smoking cessation [4 or more] weeks before surgery is associated with a decreased rate of postoperative wound infection.”

Reference

Xu B, Anderson DB, Park E-S, Chen L, Lee JH. The influence of smoking and alcohol on bone healing: systematic review and meta-analysis of nonpathological fractures. EClinicalMedicine. 2021;42:101179. doi:10.1016/j.eclinm.2021.101179