INCIDENCE, OUTCOMES, AND PREDICTORS OF ANKLE SPRAINS IN THE NATIONAL BASKETBALL ASSOCIATION

This dissertation had two primary aims: (1) describe the epidemiology of ankle sprains among National Basketball Association (NBA) players; and (2) quantify the association between history of ankle sprain and incident ankle sprain in NBA games. The NBA EMR-linked injury database was used to comprehensively examine 973 ankle sprains reported among 2,917 NBA player-seasons from 2012-13 through 2016-17. In Aim 1, the incidence and outcomes of ankle sprains that occurred among NBA players were described, including injury characteristics, player characteristics, and time lost from participation. Ankle sprains were found to affect approximately 26% of NBA players on average each season and account for a large number of missed NBA games in aggregate. In addition, players with a history of ankle sprain in the past year were noted to have elevated rates of incident ankle sprains in games. Aim 2 further investigated the influence of prior ankle sprains by assessing the association between time-dynamic ankle sprain history (meaning the number of prior ankle sprains was updated for each player at every game) in the past year and incident ankle sprain in games. The Anderson-Gill modification of the Cox proportional hazards model was used to calculate hazard ratios and 95% confidence intervals while adjusting for years in the league, body mass index, and average NBA game-minutes played in the prior year. The risk of incident ankle sprain increased linearly with increasing number of prior ankle sprains. Interestingly, the risk of re-injury was similar for both prior ipsilateral and prior contralateral sprains, suggesting that the factors that influence re-injury operate at the level of the individual (e.g. style of play, biomechanics). In summary, ankle sprains are common among NBA players and affect one in four players each season, and history of ankle sprain was associated with an increased risk of incident ankle sprain. Future research into the efficacy and effectiveness of injury prevention interventions to reduce ankle sprain incidence, as well as implementation and adherence strategies, may be beneficial for basketball players, particularly those who have a history of ankle sprain.