Pectoralis muscle injuries in Major and Minor League Baseball.

BACKGROUND AND HYPOTHESIS: Although shoulder and elbow injuries in professional baseball players have been thoroughly studied, little is known about the frequency and impact of pectoralis muscle injuries in this population. The purpose of this study was to use the official league injury surveillance system to describe pectoralis muscle injuries in professional baseball players in Major League Baseball (MLB) and Minor League Baseball (MiLB). Specifically, (1) player demographic characteristics, (2) return to play (RTP), (3) injury mechanism, (4) throwing- and batting-side dominance, and (5) injury rate per athlete exposure (AE) were characterized to guide future injury prevention strategies. METHODS: The MLB Health and Injury Tracking System database was used to compile all pectoralis muscle injuries in MLB and MiLB athletes in the 2011-2017 seasons. Injury-related data including diagnosis (tear or rupture vs. strain), player demographic characteristics, injury timing, need for surgical intervention, RTP, and mechanism of injury were recorded. Subanalyses of throwing- and batting-side dominance, as well as MLB vs. MiLB injury frequency, were performed. RESULTS: A total of 138 pectoralis muscle injuries (32 MLB and 106 MiLB injuries) were reported in the study period (5 tears or ruptures and 133 strains), with 5 of these being recurrent injuries. Operative intervention was performed in 4 athletes (2.9%). Of the 138 injuries, 116 (84.1%) resulted in missed days of play, with a mean time to RTP of 19.5 days. Starting pitchers sustained the greatest proportion of pectoralis injuries (48.1%), with pitching being the most common activity at the time of injury (45.9%). A majority of injuries (86.5%) were sustained during non-contact play. Overall, 87.5% of injuries occurred on the player's dominant throwing side and 81.3% occurred on the player's dominant batting side. There was no significant difference in the rate of pectoralis injuries in the MLB regular season (0.584 per 10,000 AEs) vs. the MiLB regular season (0.425 per 10,000 AEs) (P = .1018). CONCLUSION: Pectoralis muscle injuries are most frequently non-contact injuries, most commonly sustained by pitchers. An understanding of these injuries can guide athletic trainers and management in expectation management and decision making, in addition to directing future efforts at injury prevention.

Chronic adaptations of the long head of the biceps tendon and groove in professional baseball pitchers.

BACKGROUND AND HYPOTHESIS: The long head of the biceps tendon (LHBT) plays a significant shoulder stabilizing role during pitching, with the large forces and repetitions involved in overhead throwing likely contributing to LHBT pathology. Determining whether the LHBT undergoes adaptive changes in baseball pitchers and how these changes relate to bicipital groove morphology can improve our understanding of the biceps function at the glenohumeral joint. Therefore, the purpose of this study was to determine the chronic adaptations of the bicipital groove morphology and the LHBT in professional baseball pitchers, with a secondary purpose of evaluating biceps integrity as it relates to torsional changes of the bicipital groove. We hypothesized that the throwing arm of professional baseball pitchers would exhibit chronic adaptations of the LHBT compared with their nonthrowing arm, and that these adaptations would be related to the bicipital groove morphology. MATERIALS AND METHODS: Fifty-three professional baseball pitchers were enrolled at the beginning of the 2015 Major League Baseball spring training. Ultrasound was used to bilaterally measure humeral retroversion and to capture images of the bicipital groove and the LHBT. MATLAB software was used to calculate the area of the bicipital groove, and ImageJ software was used to quantify the area, echogenicity, and circularity of the LHBT. RESULTS: The dominant arm LHBT cross-sectional area was significantly smaller than the nondominant arm (9 mm2 vs. 10 mm2; P = .011), whereas the dominant arm LHBT echogenicity was significantly higher than the nondominant arm (65 optical density vs. 59 optical density; P = .002). Pitchers with more bicipital groove rotational adaptation (more retroversion) had significantly more LHBT echogenicity adaptation compared with pitchers with less bicipital groove rotational adaptation (12 vs. 2; P = .023). CONCLUSION: There are significant bilateral differences in the LHBT of professional baseball pitchers. An adaptation in bony rotation was associated with a larger bilateral difference in LHBT echogenicity but was not related to bilateral differences in LHBT area or circularity. Therefore, the bilateral difference in echogenicity is impacted by bony morphology, whereas the bilateral difference in cross-sectional area may be independent of bony morphology in this healthy population.

Epidemiology of acromioclavicular joint injuries in professional baseball: analysis from the Major League Baseball Health and Injury Tracking System.

BACKGROUND: Shoulder injuries account for a large portion of all recorded injuries in professional baseball. Much is known about other shoulder pathologies in the overhead athlete, but the incidence and impact of acromioclavicular (AC) joint injuries in this population are unknown. We examined the epidemiology of AC joint injuries in Major League Baseball (MLB) and Minor League Baseball (MiLB) players and determined the impact on time missed. METHODS: The MLB Health and Injury Tracking System was used to compile records of all MLB and MiLB players from 2011 to 2017 with documented AC joint injuries. These injuries were classified as acute (sprain or separation) or chronic (AC joint arthritis or distal clavicular osteolysis), and associated data extracted included laterality, date of injury, player position, activity, mechanism of injury, length of return to play, and need for surgical intervention. RESULTS: A total of 312 AC joint injuries (183 in MiLB players and 129 in MLB players; range, 39-60 per year) were recorded: 201 acute (64.4%) and 111 chronic (35.6%). A total of 81% of acute and 59% of chronic injuries resulted in time missed, with a mean length of return to play of 21 days for both. Of the injuries in outfielders, 79.6% were acute (P < .0001), as were 66.3% of injuries in infielders (P = .004). Pitchers and catchers had more equal proportions of acute and chronic AC injuries (P > .05 for all). Acute AC injuries occurred most often while fielding (n = 100, 84.7%), running (n = 25, 80.6%), and hitting (n = 19, 61.3%), whereas chronic injuries tended to be more common while pitching (n = 26, 68.4%). Of contact injuries, 82.5% were acute (P < .0001), whereas 59.0% of noncontact injuries were chronic (P = .047). MLB players showed consistently higher regular-season rates of both acute and chronic AC injuries than MiLB players (P < .0001 for each). CONCLUSION: Acute AC joint injuries are contact injuries occurring most commonly among infielders and outfielders while fielding that result in 3 weeks missed before return to play, whereas chronic AC joint injuries occur more commonly in pitchers and catchers from noncontact repetitive overhead activity. Knowledge of these data can better guide expectation management in this elite population to better elucidate the prevalence of 2 common injury patterns in the AC joint.

Epidemiology and Impact of Prior Musculoskeletal Injury and Orthopaedic Surgery on Draft Rank, Availability, and Short-term Performance in Major League Baseball: A Summary Analysis and Matched Cohort of 1890 Predraft Players.

BACKGROUND: Despite the many reports of injury rates in Major League Baseball (MLB), little is known about the epidemiology or impact of prior musculoskeletal injuries and surgical procedures among players entering the MLB draft. PURPOSE: To determine the (1) epidemiology of all musculoskeletal injuries and surgical procedures among players entering the MLB draft, (2) impact of injury or surgery on draft rank, (3) impact of injury or surgery on availability within the first 2 years of play in the MLB, and (4) impact of injury or surgery on performance. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: We retrospectively reviewed 1890 medical records that were completed by MLB team physicians as preparticipation physical assessment prior to the draft from 2014 to 2018. Players were divided into 3 groups: noninjured, nonoperative, and operative. Draft status, overall draft rank, missed games, batting average, and earned run average for the first 2 seasons of MLB play were obtained for all available players. Players across all 3 groups were compared with linear, logistic, and beta regression models, controlling for age, position, injury status, and draft rank. Unadjusted differences among groups were assessed with 1-way analysis of variance. RESULTS: Overall, 750 position players and 1140 pitchers were included, of whom 22.8% had no reported injury history; 48.8% reported injury treated nonoperatively; and 28.5% were treated operatively. The most common predraft injuries were elbow tendinitis (n = 312), ulnar collateral ligament injury (n = 212), and shoulder labral tear (n = 76). The most common predraft treatments were physical therapy (n = 922), ulnar collateral ligament reconstruction (n = 115), and fracture fixation (n = 69). Of the 1890 players, 719 were drafted and played for at least 2 years. No difference was found among noninjured, nonoperative, and operative groups in terms of draft rank, games missed, or performance. Players with a nonoperative injury had a decreased odds ratio of being drafted (0.738; P = .017). CONCLUSION: More than half of the players entering the MLB reported a history of musculoskeletal injury requiring treatment, and the most commonly affected joints were the shoulder and elbow. Musculoskeletal history did not affect draft rank, short-term availability, or performance for MLB prospects.

Effects of Ulnar Collateral Ligament Reconstruction on Pitch Selection in Major League Baseball Pitchers.

BACKGROUND: Ulnar collateral ligament (UCL) injuries represent one of the most common impairments to the throwing arm of professional pitchers. Return to play and postoperative performance metrics have been studied extensively, but pitch selection before and after surgery has not been evaluated. PURPOSE/HYPOTHESIS: This study aimed to characterize the effects of UCL reconstruction on pitch selection in Major League Baseball (MLB) pitchers. We hypothesized that pitchers will throw fewer fastballs and a greater percentage of off-speed pitches after undergoing UCL reconstruction. STUDY DESIGN: Retrospective cohort study; Level of evidence, 3. METHODS: Using publicly available data, we evaluated MLB pitchers who underwent UCL reconstruction between 2003 and 2014. Pitching data were collected for the 2 seasons before UCL reconstruction as well as the first 2 seasons after reconstruction; the data consisted of the total number of pitches thrown and the percentage of fastballs, curveballs, changeups, and sliders. Repeated-measures analysis of variance was used with post hoc least significant difference pairwise t tests to evaluate for statistical significance at P < .05. RESULTS: Overall, 87 pitchers (mean age, 28.2 ± 3.5 years) met all inclusion and exclusion criteria. There was a statistically significant difference in the total number of pitches thrown before and after surgery (P < .01) as well as in the percentage of fastballs thrown before and after surgery (P = .02). There was also a statistically significant increase in the use of curveballs between 1 and 2 years postoperatively (7.5% and 8.8%, respectively; P = .01). No other findings were statistically significant. CONCLUSION: Pitchers who underwent UCL reconstruction were shown to have a statistically significant decline in the percentage of fastballs thrown postoperatively as compared with before injury, with a compensatory trend toward an increased use of curveballs and sliders.

Magnetic Resonance Imaging Predictors of Failure in the Nonoperative Management of Ulnar Collateral Ligament Injuries in Professional Baseball Pitchers.

BACKGROUND: A medial ulnar collateral ligament (UCL) injury of the elbow is an increasingly common injury in professional baseball pitchers. Predictors of success and failure are not well defined for the nonoperative management of these injuries. PURPOSE: To evaluate the efficacy of objective measures to predict failure of the nonoperative management of UCL injuries. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: Thirty-two professional pitchers (82%) met inclusion criteria and underwent an initial trial of nonoperative treatment for UCL tears based on clinical and radiological findings. Age, preseason physical examination results, magnetic resonance imaging (MRI) characteristics, and performance metrics were analyzed for these pitchers. Successful nonoperative management was defined as a return to the same level of play or higher for >1 year. Failure was defined as recurrent pain or weakness requiring a surgical intervention after a minimum of 3 months' rest when attempting a return to a throwing rehabilitation program. RESULTS: Thirty-two pitchers (mean age, 22.3 years) who underwent initial nonoperative treatment of UCL injuries were evaluated. Thirty-four percent (11/32) failed and required subsequent ligament reconstruction. Sixty-six percent (21/32) successfully returned to the same level of play for 1 year without a surgical intervention. There was no significant difference seen in physical examination findings or performance metrics between these patients. When comparing MRI findings between the groups, 82% (9/11) ( P < .001) who failed nonoperative management had distal tears, and 81% (17/21) who did not fail had proximal tears ( P < .001). When adjusting for age, location, and evidence of chronic changes on MRI, the likelihood of failing nonoperative management was 12.40 times greater ( P = .020) with a distal tear. No other variable alone or in combination reached significance. When combining the parameters of a high-grade tear and distal location, 88% (7/8) failed nonoperative management. CONCLUSION: In professional pitchers, distal UCL tears showed significantly higher odds of failure with nonoperative management compared with proximal tears. Thus, tear location should be considered when deciding between operative and nonoperative management.