Injury Scenarios of Ankle Sprains in the National Football League: External Rotation and Eversion Mechanisms

Ankle sprains in American football resulting from external rotation and eversion (EE) mechanisms remain a persistent injury that often involves player-to-player contact. Currently, there is little research that describes the frequency or source of this contact in American football and what scenarios are responsible for these injuries across different player positions.

To identify injury scenarios of ankle sprains that result from EE mechanisms in the National Football League (NFL).

Descriptive epidemiology study.

Ankle sprains reported during NFL games over 4 consecutive seasons (2017-2020) were identified through a query of the NFL Electronic Medical Record by an independent epidemiological company based on a set of clinical impression codes. Injuries with available video to view the injury enabled the identification of ankle sprains that resulted from EE mechanisms. Standardized terminology was developed to systematically describe and categorize each injury.

A total of 257 ankle sprains resulting from EE mechanisms were identified from a review of 670 ankle sprains and grouped into 8 standardized injury scenarios. Direct contact to the injured player's foot, ankle, or leg from a large external mass, such as an opponent's pelvis, accounted for 79% of reviewed injuries. Direct contact from a large external mass was the most common scenario for all positions except safeties, and 83% of running back injuries were the result of a tackle. Only 15% of injuries reviewed resulted from injury scenarios in which injurious loading was transmitted solely through the cleat-surface interaction. Safeties and cornerbacks were more commonly involved in these nondirect injury scenarios, such as change of direction, where current interventions may prove more effective.

EE ankle sprains were observed to occur from 8 different injury scenarios that varied by player position. Interventions through training, bracing, or changing cleat-surface interaction may not be effective for all injury scenarios. Tackling technique may be a unique intervention for running backs.