Epidemiology and Outcomes of Ankle Injuries in the National Football League

Abstract

Background: Traumatic ankle injuries are commonly complicated by persistent symptoms and the development of chronic ankle instability. Purpose: To describe the epidemiology of ankle injuries in the National Football League (NFL) and investigate the effects that ankle injuries have on performance metrics in the years after injury. Study Design: Descriptive epidemiologic study. Methods: Ankle injuries sustained by NFL players during the 2015-2016, 2016-2017, and 2017-2018 seasons were identified using the Pro Football Reference database. Cumulative incidence was calculated, and demographic identifiers were collected for each injury. The return-to-play (RTP) rate was also recorded. For each player who met inclusion for the performance analysis, power rating (PR) was calculated for the preinjury season (Y–1) and 2 postinjury seasons (Y+1 and Y+2) as follows: PR = (offensive yards/10) + (total touchdowns × 6) + (combined tackles) + (sacks × 2) + (interceptions × 2). Mean PRs were calculated for each season as well as the percentage change and mean difference in PR between Y–1 and Y+1 (ΔPR1%, ΔPR1) and between Y–1 and Y+2 (ΔPR2%, ΔPR2). Subgroup analyses of PR were performed by player position, injury type, and years of experience. Results: Overall, 668 ankle injuries were identified, with an average cumulative incidence across the 3 seasons of 11.2% and RTP rate of 91%. Of those injuries, 159 met inclusion criteria for the PR analysis. The mean overall PR (96.95 in Y–1) declined 22% in Y+1 to 76.10 (–20.85 [95% CI, –13.82 to –27.89]; P