Search

BackgroundFractures are a significant cause of missed time in Major League Baseball (MLB) and Minor League Baseball (MiLB). MLB and the MLB Players Association recently instituted rule changes to limit collisions at home plate and second base.PurposeTo evaluate the epidemiologic characteristics of fractures in professional baseball and to assess the change in acute fracture incidence secondary to traumatic collisions at home plate and second base after the recently instituted rule changes.Study designDescriptive epidemiology study.MethodsThe MLB Health and Injury Tracking System (HITS) database was used to access injury information on MLB and MiLB players to analyze fracture data from 2011 to 2017. Injuries were included if the primary diagnosis was classified as a fracture in the HITS system in its International Classification of Diseases, Ninth Revision, codes; injuries were excluded if they were not work related, if they occurred in the offseason, or if they were sustained by a nonplayer. The proportion of fractures occurring due to contact with the ground or another person in the relevant area of the field-home plate or second base-in the years before rule implementation was compared with the years after.ResultsA total of 1798 fractures were identified: 342 among MLB players and 1456 among MiLB players. Mean time missed per fracture was 56.6 ± 48.4 days, with significantly less time missed in MLB (46.8 ± 47.7 days) compared with MiLB (59.0 ± 48.3 days) (P < .0001). A 1-way analysis of variance with post hoc Bonferroni correction demonstrated that starting pitchers missed significantly more time due to fractures per injury than all other position groups (P < .0001). Acute fractures due to contact with the ground or with another athlete were significantly decreased after rule implementation at home plate in 2014 (22 [3.0%] vs 14 [1.3%]; P = .015) and at second base in 2016 (90 [7.0%] vs 23 [4.5%]; P = .045).ConclusionThe recently instituted rule changes to reduce collisions between players at home plate and at second base are associated with reductions in the proportion of acute fractures in those areas on the field.

Background:Ulnar collateral ligament (UCL) reconstruction is frequently performed on Major League Baseball (MLB) pitchers. Previous studies have investigated the effects of UCL reconstruction on fastball and curveball velocity, but no study to date has evaluated its effect on fastball accuracy or curveball movement among MLB pitchers.Purpose/Hypothesis:The primary purpose of this study was to determine the effects of UCL reconstruction on fastball accuracy, fastball velocity, and curveball movement in MLB pitchers. Our hypothesis was that MLB pitchers who underwent UCL reconstruction would return to their presurgery fastball velocity, fastball accuracy, and curveball movement. The secondary purpose of this study was to determine which factors, if any, were predictive of poor performance after UCL reconstruction.Study Design:Case-control study; Level of evidence, 3.Methods:MLB pitchers who underwent UCL reconstruction surgery between 2011 and 2012 were identified. Performance data including fastball velocity, fastball accuracy, and curveball movement were evaluated 1 year preoperatively and up to 3 years of play postoperatively. A repeated-measures analysis of variance with a Tukey-Kramer post hoc test was used to determine statistically significant changes in performance over time. Characteristic factors and presurgery performance statistics were compared between poor performers (>20% decrease in fastball accuracy) and non—poor performers.Results:We identified 56 pitchers with a total of 230,995 individual pitches for this study. After exclusion for lack of return to play (n = 14) and revision surgery (n = 3), 39 pitchers were included in the final analysis. The mean presurgery fastball pitch-to-target distance was 32.9 cm. There was a statistically significant decrease in fastball accuracy after reconstruction, which was present up to 3 years postoperatively ( P = .007). The mean presurgery fastball velocity of 91.82 mph did not significantly change after surgery ( P = .194). The mean presurgery curveball movement of 34.49 cm vertically and 5.89 cm horizontally also did not change significantly ( P = .937 and .161, respectively).Conclusion:Fastball accuracy among MLB pitchers significantly decreased after UCL reconstruction for up to 3 years postoperatively. There were no statistically significant differences in characteristic factors or presurgery performance statistics between poor and non--poor performers.

Background: Variations in batting technique may put baseball players at increased risk of hook of the hamate fractures. A better comprehension of the mechanism of such fractures is needed. Purpose/Hypothesis: The purpose of the study was to compare 2 different grip types to quantify the pressures exerted on the hook of the hamate during batting. It was hypothesized that when compared with the conventional batting style, players holding the knob of the bat in the palm of the hand (termed the “palmar hamate grip”) would have higher pressures exerted on the hook of the hamate. Study Design: Controlled laboratory study. Methods: Athletes were recruited for participation on a volunteer basis from the rosters of 2 National Collegiate Athletic Association Division I baseball teams and were divided into 2 groups based on their usual grip type. A force sensor system was applied to the nondominant hand of each participating player, with the central portion of the sensing mechanism placed on the batting glove directly over the hook of the hamate. All players used the same batting glove, which transmitted data from the sensor to a laptop computer. Measurements were collected on consecutive hits at a standardized distance using a ball machine at 70 mph. Results: Nine collegiate baseball players underwent testing (5 players exclusively used the conventional grip, 3 players exclusively used the palmar hamate grip, and 1 player naturally alternated between the 2 grip types). The palmar hamate grip demonstrated a 366% increase in pressure exerted on the sensor overlying the hook of the hamate when compared with the conventional batting grip (536.42 kPa [95% confidence interval, 419.39-653.44 kPa] vs 115.84 kPa [95% confidence interval, 96.97-135.10 kPa]). The player who used both grips demonstrated significantly higher maximum pressure when using the palmar hamate versus conventional grip (482.90 vs 142.40 kPa; t = 6.95; P < .0001). Conclusion: Use of the palmar hamate grip may increase the risk of hook of the hamate fracture in National Collegiate Athletic Association Division I baseball players. Clinical Relevance: Educating players on the risks associated with the palmar hamate grip may prevent injury and minimize time out of competition.

Context: The overhand pitch is one of the fastest known human motions and places enormous forces and torques on the upper extremity. Shoulder and elbow pain and injury are common in high-level pitchers. A large body of research has been conducted to understand the pitching motion. Evidence Acquisition: A comprehensive review of the literature was performed to gain a full understanding of all currently available biomechanical and clinical evidence surrounding pitching motion analysis. These motion analysis studies use video motion analysis, electromyography, electromagnetic sensors, and markered motion analysis. This review includes studies performed between 1983 and 2016. Study Design: Clinical review. Level of Evidence: Level 5. Results: The pitching motion is a kinetic chain, in which the force generated by the large muscles of the lower extremity and trunk during the wind-up and stride phases are transferred to the ball through the shoulder and elbow during the cocking and acceleration phases. Numerous kinematic factors have been identified that increase shoulder and elbow torques, which are linked to increased risk for injury. Conclusion: Altered knee flexion at ball release, early trunk rotation, loss of shoulder rotational range of motion, increased elbow flexion at ball release, high pitch velocity, and increased pitcher fatigue may increase shoulder and elbow torques and risk for injury.

Background: Humeral retroversion angles determined by previous techniques are varied and/or biased by morphologic variations of the proximal and distal humerus, and their validity should be revisited. To overcome the limitations of previous studies associated with 2-dimensional (2D) images and the reference axes, a 3-dimensional (3D) measurement of humeral retroversion is required. However, comparisons of 2D imaging methods with the 3D computed tomography (CT) measurement as a reference standard have not been heretofore performed. Purpose: To determine whether the 3D CT humeral retroversion angle in baseball players is correlated with conventional humeral retroversion measurements. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 28 humeri from 14 male baseball players were used for measuring humeral retroversion. Participants underwent CT scans, and geometric bone models were created for measuring the 3D CT humeral retroversion angle. Using CT slices, the 2D CT humeral retroversion angle was also determined. Bicipital forearm angle was assessed using the indirect ultrasound technique. Linear regressions and Bland-Altman plots were used to determine whether there were agreements among 3 variables: the 3D CT retroversion, 2D CT retroversion, and bicipital forearm angles. Results: In linear regression analyses, the 3D humeral retroversion angle was not predicted by the 2D CT retroversion ( R = 0.167, R2 = 0.028, P = .395) or the bicipital forearm angle ( R = 0.049, R2 = 0.002, P = .805). The bias of these 2 methods was 20.9° and –15.3°, respectively. Regression analysis demonstrated that the bicipital forearm angle was a significant predictor of the 2D CT retroversion angle ( R = 0.632, R2 = 0.400, P < .001). Conclusion: The 3D CT humeral retroversion angle was found to be underestimated by the 2D CT retroversion angle and overestimated by the bicipital forearm angle obtained by the indirect ultrasound, although a previously observed relationship between the 2D CT retroversion and bicipital forearm angles was confirmed. Clinical Relevance: Precise measurement of humeral retroversion angle is important because retroversion has been linked to upper extremity disorders, including throwing-related shoulder and elbow disorders in baseball players.