Epidemiology of Acromioclavicular Sprains in the National Football League, 2015-2021

BACKGROUND: Acromioclavicular (AC) joint injuries are common in the National Football League (NFL), but outdated studies may not reflect current injury patterns. PURPOSE: To investigate time-loss AC sprains sustained in the NFL and describe epidemiologic injury trends across the 2015-2021 seasons. STUDY DESIGN: Descriptive epidemiology study. LEVEL OF EVIDENCE: Level 3. METHODS: Data from the 2015-2021 seasons were collected from patients or other participants from NFL players from 32 teams. Athlete risk of injury, injury rates, and severity were calculated overall and by position during games and practices. RESULTS: From 2015 to 2021, 520 missed-time AC sprains were documented, averaging 74.3 injuries per year. Most occurred during regular-season games (64%), resulting in an overall incidence rate (IR) of 0.49 (95% CI, 0.44-0.54) per 10,000 player-plays. Players missed an average of 15.2 days per injury, with tight ends and running backs experiencing the greatest time loss in days missed. Average time lost increased with injury severity, averaging 9.7 (grade 1), 17.8 (grade 2), and 41.4 (grade 3) days. A total of 76% of game-related AC sprains occurred during the regular season (IR: 1.86 per 1,000 player games; 95% CI, 1.66-2.08). Sprains occurring during preseason games had the highest rate of time-loss injury (IR, 0.62 per 10,000 player-plays; 95% CI, 0.5-0.77). Running backs (IR, 0.95; 95% CI, 0.68-1.32), tight ends (IR, 0.79; 95% CI, 0.55-1.12), wide receivers (IR, 0.77; 95% CI 0.59-1.00), and quarterbacks (IR, 0.64; 95% CI, 0.39-1.04) had the highest IRs per 10,000 player-plays in regular season games. CONCLUSION: AC sprains account for many players missing time during the season, with grade 1 being the most common and increasing severity correlating with increased time-loss. While most injuries occurred in defensive secondary players, running backs, tight ends, wide receivers, and quarterbacks had the highest injury rates per play. CLINICAL RELEVANCE: AC sprains significantly impacted player availability, highlighting the need for targeted management including shoulder pad fit/modifications and bracing.