Analysis of baseball-to-helmet impacts in major league baseball.

BACKGROUND: In Major League Baseball (MLB), helmet hit-by-pitch (H-HBP) incidents are a leading cause of concussion. However, not all H-HBPs result in diagnosed concussion.

PURPOSE: This study was designed to (1) quantify batter concussion risk as a function of H-HBP pitch velocity, time duration batter spent on the ground post-H-HBP, first responder assessment time duration, and number of days missed post-H-HBP and (2) estimate H-HBP impact locations on the helmet with respect to current National Operating Committee on Standards for Athletic Equipment (NOCSAE) helmet test standards and correlate impact locations with concussion diagnosis.

STUDY DESIGN: Case-control study; Level of evidence, 3.

METHODS: A retrospective case-control study of 18 MLB players with H-HBP incidents in the 2009 and 2010 seasons was undertaken. A database was compiled via quantitative and qualitative analysis using video coverage obtained from MLB. Quantitative factors included batter concussion diagnosis, pitch velocity, number of days missed post-H-HBP, time duration batter spent on the ground post-H-HBP, and first responder assessment time duration. The H-HBP impact location was among several qualitative factors developed via video analysis of each H-HBP from 4 raters.

RESULTS: In our study, 9 players (50%) were diagnosed with concussion. Concussion diagnoses were more frequent for posterior versus anterior impacts. The majority of H-HBP impact locations were different from those in the current NOCSAE standard tests. First responders took an average of approximately 65 seconds (time to reach batter plus assessment time) to decide on batter removal/return to play. The 25% logistic regression concussion risk threshold for pitch velocity and days missed was 86.2 mph and 1.3 days, respectively. The number of days missed after H-HBP showed a significant correlation (P = .02) among concussed and nonconcussed batters.

CONCLUSION: In professional baseball H-HBP incidents, first responders should (1) be aware of pitch velocity in excess of 86 mph and (2) be provided ample time when assessing batters' removal/return to play.

CLINICAL RELEVANCE: First responders should not rely solely on visual indicators such as batter reaction, holding head, or amount of time spent on the ground after H-HBP when assessing batters for concussion. Batting helmets in the MLB should maximize protection and mitigate impact dosage for H-HBP impact locations and velocity in addition to NOCSAE standard test locations and velocities.