Conway, Justin

Objective: To generate a summative report on the most commonly diagnosed illnesses in Major League Baseball (MLB) and Minor League Baseball (MiLB) athletes with specific attention to their impact based on time out of play. Design: Retrospective analysis. Setting: Injury and illness data from the MLB Health and Injury Tracking System. Participants: All MLB and MiLB athletes active between 2011 and 2016. Assessment of Risk Factors: Illnesses were defined as atraumatic medical diagnoses that occurred during the MLB or MiLB season and resulted in at least 1 day out of play. Main Outcome Measures: Incidence of illness diagnoses and resulting time out play. Results: Eight thousand eight hundred thirty-four illnesses were reported, representing 14.7% of all diagnoses resulting in time out of play. Total days missed (DM) due to illness were 39 614, with a mean of 4.6 (SD 9.9 days) and median 2 DM per diagnosis. The annual incidence of illness per season was 20.3 per 100 athletes. The most common diagnosis was nonspecific viral illness (15.3%), followed by gastroenteritis (13.6%), other gastrointestinal illness (8.3%), influenza (7.0%), and upper respiratory infection (6.2%). Appendicitis (15.2%) and Epstein–Barr virus/cytomegalovirus (9.1%) were the most common season-ending diagnoses. Conclusions: Illnesses represent a significant cause of time out of play in MLB and MiLB. Prevention efforts should focus on limiting the spread of communicable viral, respiratory, and gastrointestinal disease among players, as the majority of diagnoses fell into these categories. This work may be used to guide future research into illness treatment and prevention in professional baseball.

Background: Recent epidemiologic reports have demonstrated rising injury rates in Major League Baseball (MLB) and Minor League Baseball (MiLB). Although several studies have recently been published on specific injuries, the majority of injuries have not yet been formally studied. Purpose: The purpose of this study is to (1) generate a summative analysis of all injuries that occur in MLB and MiLB, (2) identify the 50 most common injuries, and (3) generate focused reports and fact sheets on the characteristics of each of those diagnoses. Study Design: Case series; Level of evidence, 4. Methods: The MLB Health and Injury Tracking System was used to identify injuries occurring in MLB and MiLB players from 2011 to 2016. Injuries were defined as those that occurred during normal baseball activity and resulted in at least 1 day out of play. A multitude of player and injury characteristics were analyzed, and detailed reports of the 50 most commonly occurring injuries were generated. Results: A total of 49,955 injuries occurred during the study period; 45,123 were non–season ending, and they resulted in 722,176 days out of play. The mean (median) days missed per injury was 16 (6) days. Overall, 39.1% of all injuries occurred in pitchers. The upper extremity was involved in 39% of injuries, while 35% occurred in the hip/groin/lower extremity. Surgery was required in 6.5% of cases, and 9.7% of injuries were season ending. Hamstring strains were the most common injury (n = 3337), followed by rotator cuff strain/tear (n = 1874), paralumbar muscle strain (n = 1313), biceps tendinitis (n = 1264), oblique strain (n = 1249), and elbow ulnar collateral ligament injury (n = 1191). The diagnoses that were most likely to end a player’s season were elbow ulnar collateral ligament injury (60% season ending) and superior labrum anterior and posterior tear (50.9% season ending). Conclusion: Contrary to prior reports relying on disabled list data, the annual number of injuries in professional baseball remained steady from 2011 to 2016. Similar trends were noted for the annual number of days missed and mean days missed per injury. Although the mean days missed per injury was high (16), the median was much lower at 6 days.