The Impact of Smoking on Outcomes Following Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-Analysis

The influence of smoking on postoperative outcomes following anterior cruciate ligament (ACL) reconstruction is a topic of ongoing scientific discussion and uncertainty. We aimed to conduct a systematic review and meta-analysis to compare the outcomes between smokers and non-smokers undergoing this procedure. We conducted a systematic search of electronic information sources, including MEDLINE, EMBASE, CINAHL, CENTRAL, ClinicalTrials.gov, and bibliographic reference lists. We applied a combination of free-text search and controlled vocabulary search adapted to thesaurus headings, search operators, and limits in each of the above-mentioned databases. Primary outcome parameters included surgical site infections, ACL graft rupture, revision rates, and patient-reported outcome measures (PROMs). We identified 24 comparative studies, including a total of 672,241 patients, of whom 69,113 were in the smoker group and 603,128 were in the non-smoker group. The analysis revealed that smoking was associated with a significantly higher risk of surgical site infections (OR 1.40, P=0.01). Smokers also reported significantly worse PROMs on the International Knee Documentation Committee (IKDC) score (MD -5.38, P<0.00001) and multiple Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales. There was no statistically significant difference between the two cohorts for ACL graft rupture or all-cause revision rates. Smoking appears to be associated with a higher risk of surgical site infections following ACL reconstruction and is linked to significantly poorer functional PROMs.