Higher BMI predicts additional surgery at the time of ACL reconstruction.

Purpose: Despite public recognition, obesity is a growing epidemic affecting an estimated 34% of adults and 20% of children in the U.S.

Population: As such, the number of ACL reconstructions performed in this population is likely to increase. The goal of this study is to evaluate the risk that increasing BMI poses for additional surgery at the time of ACL reconstruction.

Methods: A retrospective analysis of the American College of Surgeons' National Surgical Quality Improvement Program's (ACS-NSQIP) database for the years 2005-2015 was conducted. Logistic regressions were used to assess the relationship between BMI and additional CPT codes for internal derangement at the time of ACL reconstruction. Internal derangement was defined as any CPT code for treatment of a meniscus tear, chondral lesion, or loose body removal. Surgeries for multi-ligamentous knee injuries were excluded.

Results: A total of 11,403 patients undergoing ACL reconstruction were identified. 41.9% of patients had an associated CPT code for internal derangement. As BMI increased, there was a corresponding increase in the odds of additional surgery. Specifically, for every 1.0 increase in BMI, the risk of additional surgery increased by 1.6% (p < 0.001). Compared to patients with a BMI of 18.5-24.9, those with a BMI 25-29.9 had an odds ratio (OR) of 1.112, BMI 30-34.9 had an OR of 1.137, BMI 35-39.9 had an OR of 1.249, and those ≥ 40 had an OR of 1.442 for additional surgery (p < 0.001).

Conclusions: This nationally-representative, population-based study demonstrates that patients with elevated BMI are much more likely to require additional surgery in the setting of primary ACL reconstruction. This risk correlates with increasing BMI. Surgeons should keep these risks in mind when evaluating and counseling patients for surgery in the setting of ACL reconstruction.

Level of evidence: Case-control study, Level III.