Modifiable Risk Factors

Three high (Molina 2015, Chan 2019, Esposito (2019), ten moderate (Enninghost 2011, Su 2017, Li 2020, Olson 2021, Bai 2019, Morris 2013, Clegg 2019, Sagi 2017, Hendrickson 2020, Castillo 2005), and two low quality studies (Pollak 2010, Adams 2001) investigated the effect of smoking on SSI. There were mixed findings with 40% of these papers finding an increased risk of SSI in smokers and 60% finding no difference in SSI between smokers and non-smokers. However, some of these studies that did not identify a difference in the two groups were likely underpowered to be able to discern a difference. 

Two high (Chan 2019, Molina 2015), four moderate (Hendrickson 2020, Li 2020, Bai 2019, Clegg 2019), and two low quality studies (Kline 2009, Ricci 2014) investigated the effect of diabetes on SSI. Again, there were mixed findings with 62.5% of the studies finding an increased risk for SSI in patients with diabetes and 37.5% of the studies finding no difference. 

One high (Chan 2019) and three moderate quality studies (Olson 2021, Bai 2019, Su 2017) investigated the effect of obesity on SSI. Chan (2019) and Olson (2021) observed no increase in risk for SSI following ORIF of tibial plafond and tibial plateau fractures in obese patients as compared to patients who were not obese whereas Bai (2019) and Su (2017) noted an increased risk for SSI in obese patients with femoral and calcaneal fractures. 

One high quality study (Chan 2019) investigated the effect of alcohol on SSI and reported that alcohol use >14 units per week significantly increased the likelihood of surgical site infection.

One high quality study (Stall 2013) investigated the effect of high flow perioperative O2 on the risk for SSI but observed no difference in risk for infection in patients with high (80%) or low (30%) FI02 perioperative oxygen. 

One moderate quality study (Bai 2019) investigated the effect of low albumin on SSI and noted a higher risk for deep infection in patients with preop albumin <36g/L as compared to those with preoperative albumin >36g/L. 

One moderate quality study (Ren 2015) investigated the effect of blood glucose on SSI and reported an increased risk for infection in patients with elevated postoperative glucose levels when compared to patients with glucose <125 mg/dL. 

One moderate quality study (Weber 2014) investigated the effect of transfusion on SSI but failed to identify any significant difference in the risk of deep infection in patients who received a transfusion as compared to those that did not. 

One moderate quality study (Waikakul 1998) investigated the need for intraoperative vascular surgery consultation for Gustilo type 3A/3B open lower extremity fractures and reported that although this exploration did improve chronic swelling, decrease paresthesias and decrease the risk for re-grafting, it did not alter the risk for SSI. 

One moderate quality study (Saveli 2013) observed no increased risk of superficial SSI, MSSA/MRSA deep infection or any deep infection when patients were noted to have preoperative MRSA colonization as compared to those that were not. 

Benefits & Harms

Modification of these risk factors, when possible, has the potential to significantly decrease postoperative infection in patients with major extremity trauma. 

Outcome Importance

This data provides information that may improve patient counseling in the perioperative period. While these risk factors are modifiable, surgical treatment of these fractures is generally performed on an urgent basis with a timeline that generally does not allow preoperative alteration of these risk factors.  Although some of these risk factors can be modified in the immediate postoperative period, it is unclear how this may or may not influence outcomes. 

Cost Effectiveness/Resource Utilization

This recommendation allows physicians, hospitals and payors to better counsel patients and align expectations with respect to the increased risk factors for SSI. 

Acceptability

Medical optimization is performed when possible perioperatively. This information can help inform clinicians as to what modifiable risk factors should be targeted in the immediate perioperative period. 

Feasibility

Medical optimization can be undertaken while a patient is still in the hospital for their injury. Other modifiable risk factors such as alcohol use, smoking and glycemic control require patient comprehension and compliance to have any reasonable expectation of positively influencing outcomes. 

Future Research

Many of these studies are retrospective in nature and may not be powered to fully describe the various risk factors for SSI after major lower extremity trauma. Therefore, further prospective research with larger cohorts, perhaps in a trauma registry, would assist in further elucidating these risk factors.