Study data presented at the AAOS 2013 Annual Meeting revealed that smoking is associated with increased nonunion rates, longer healing times, and higher rates of wound complications in long-bone fractures.

Although cigarette smoking is recognized as one of the major causes of preventable disease in the United States, little reported analysis exists regarding the effects of smoking on fracture healing and postoperative infection after long-bone fracture surgery, according to the authors.

Led by Mara L. Schenker, MD, researchers at the University of Pennsylvania conducted a comprehensive literature review and meta-analysis to assess the association between smoking and long-bone fracture union, time to union, and related soft-tissue complications, including infection. Only studies published in English were reviewed. Inclusion criteria were the following:

• Level 1, 2, or 3 evidence
• Study patients older than 18 years
• Study groups of 15 or more patients
• Long-bone or long-bone periarticular (eg, proximal humerus, distal radius, pilon) fractures
• Cigarette smoking as a patient characteristic
• Documentation of complications (delayed union, nonunion, wound complication/infection)

Randomized controlled trials and prospective and retrospective studies were included; case reports, review articles, and articles editorial in nature were excluded.

A total of 20 clinical studies (7 prospective and 13 retrospective cohort studies) met the inclusion and exclusion criteria. The studies involved 6,480 patients (1,457 smokers and 5,023 nonsmokers) with fractures of the tibia, femur or hip, ankle, humerus, and multiple long bones. Fractures were managed both nonsurgically and surgically via external fixation, intramedullary nailing, and plate fixation; most studies included patients treated with multiple methods.

The researchers performed meta-analysis using a random effects model to evaluate nonunion and superficial and deep infections in the smoking and nonsmoking cohorts. Time to healing was evaluated using frequency-weighted means and group-weighted standard deviations.

Smoking increases complications
The researchers found that smokers had higher odds of overall long-bone fracture nonunion (15 percent), tibia fracture nonunion (15 percent), and open-fracture nonunion (12 percent), compared to nonsmokers. In addition, the superficial infection rate was higher for smokers than for nonsmokers (7 percent and 4 percent, respectively) and the deep infection rate was also higher for smokers than for nonsmokers (7 percent and 2 percent, respectively).

The researchers also noted that in the eight studies that evaluated healing times, the mean fracture healing time for smokers was 30.2 weeks, compared to 24.1 weeks for nonsmokers, which suggests a trend toward prolonged healing times in the smoking group (P = 0.18). For tibia fractures alone, the mean healing time was 32 weeks for smokers, compared to 25.1 weeks for nonsmokers (P = 0.18) (Table 1).

“Our study, which provided a comprehensive systematic review of the effects of smoking on fracture healing and infection, found that smoking was associated with increased nonunion rates for all fractures, tibia fractures, and open fractures. In addition, there was a trend toward higher rates of surgical and open fracture-related wound healing complications in patients who smoked,” said Dr. Schenker.

She added, “Based on these results, orthopaedic surgeons should advise their fracture patients about the risks of smoking, and smoking intervention programs should be implemented to promote better postfracture outcomes.”

Dr. Schenker’s coauthors of “Blowing Smoke: A Meta-Analysis of Smoking on Fracture Healing and Postoperative Infection” are John A. Scolaro, MD; Sarah M. Yannascoli, MD; Keith D. Baldwin, MD; Samir Mehta, MD; and Jaimo Ahn, MD, PhD.

Disclosure information: Dr. Baldwin—Pfizer; Synthes; Journal of Bone and Joint Surgery–American. Dr. Mehta—Zimmer; Smith & Nephew; AO North America; Synthes; Amgen; Medtronic; Wolters Kluwer Health–Lippincott Williams & Wilkins; Current Opinion in Orthopaedics; Pennsylvania Orthopaedic Society. Dr. Ahn—Merck; Synthes; Orthopaedia.com; AAOS, Basic Science Evaluation Subcommittee; Foundation for Orthopedic Trauma, Research Committee; American Physician Scientists Association Board of Directors; NBME committee for USMLE surgery test material development. Drs. Schenker, Scolaro, and Yannascoli—no conflicts.

Read the abstract…

Maureen Leahy is assistant managing editor of AAOS Now. She can be reached at leahy@aaos.org

Bottom Line

• Little reported analysis exists regarding the effects of smoking on fracture healing and postoperative infection after long-bone fracture surgery.
• Meta-analysis revealed that smoking is associated with a higher rate of nonunion in all long-bone fractures, tibia fractures, and open fractures.
• Smoking can also result in longer healing times and a higher risk of infection.
• Orthopaedic surgeons should discuss these risks with fracture patients who smoke.