Search

Background: The forearm flexor-pronator muscles act as a dynamic elbow stabilizer against elbow valgus load during baseball pitching. The elasticity of these muscles increases with pitching. However, it is unclear whether increased muscle elasticity is associated with greater elbow valgus torque during pitching. This study aimed to determine the relationship between the elasticity of the forearm flexor-pronator muscles and elbow valgus torque during pitching in young baseball pitchers., Methods: We recruited 124 young baseball pitchers aged 9 to 12 years. The exclusion criteria included current pain with pitching, history of surgery on the tested extremity, or injuries on the tested extremity within the past 12 months. Before the examination, participants completed a questionnaire about their age, height, weight, dominant arm, and practice time per week. The strain ratios of flexor carpi ulnaris (FCU), flexor digitorum superficialis (FDS), and pronator teres as the index of muscle elasticity were measured using ultrasound strain elastography. Participants pitched 3 fastballs at a distance of 16 m (52 ft 6 in) with maximum effort while wearing a sensor sleeve that recorded the elbow valgus torque. A multiple linear regression analysis was conducted to examine the association between muscle elasticity and elbow valgus torque, adjusting for age, height, weight, and practice time., Results: The final analysis included 107 pitchers. After adjusting for covariates, increased strain ratio of the FCU was significantly associated with greater elbow valgus torque (coefficients = 0.038, 95% confidence interval, 0.016-0.059, P < .001). Similarly, increased strain ratio of the FDS was significantly associated with greater elbow valgus torque (coefficients = 0.027, 95% confidence interval, 0.013-0.042, P < .001)., Conclusion: The high elasticities of the FCU and FDS were associated with greater elbow valgus torque during pitching in young baseball pitchers. The high elasticity of these muscles is a protective response and may be necessary for young baseball pitchers with greater elbow valgus torque during pitching. Among young baseball pitchers with greater elbow valgus torque, those who are unable to produce the higher elasticities of these muscles could have greater elbow valgus load during pitching and be at a higher risk for elbow injuries. The measurement of the elasticities of the FCU and FDS may be useful for identifying young baseball pitchers at risk of sustaining elbow injuries., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Overhead athletes are particularly susceptible to elbow valgus extension overload syndrome and development of pathologic changes in the posteromedial elbow. Though arthroscopic débridement/osteophyte resection is frequently performed, few studies have analyzed the outcomes of this procedure and none have specifically addressed professional level athletes., Hypothesis: We hypothesized that following posteromedial elbow débridement, Major League Baseball (MLB) pitchers would exhibit a higher rate of ulnar collateral ligament (UCL) reconstruction than baseline incidence in the existing literature, along with a decline in pitching performance., Methods: Using publicly accessible websites, MLB athletes undergoing posteromedial elbow débridement from 2007 to 2022 were identified. Demographic information, procedure details, return to play (RTP) information, return to the disabled/injured list (DL/IL), subsequent UCL reconstruction, and pitching statistics were analyzed. Pitching performance metrics included earned runs average, walks plus hits per innings pitched, innings pitched, and fastball velocity., Results: A total of 39 MLB players, including 26 pitchers, were included. Within the first three seasons after surgery, 82.1% (n = 32) of players returned to play at the MLB level at a mean time of 176.1 ± 69 days. Pitchers exhibited a RTP rate of 76.9% (n = 20) at 175.8 ± 16 days. A total of 38.5% (n = 10) of pitchers returned to the DL/IL for elbow-related issues within three seasons. Subsequent UCL reconstruction was seen only in pitchers, with a frequency of 19.2% (n = 5). No statistically significant differences between single season preoperative/postoperative pitching metrics were identified. A small but significant (P < .05) decrease in fastball velocity (94.4 vs. 92.84; P = .02) was observed over a three-season comparison., Conclusion: Contrary to our hypothesis, this study demonstrates that posteromedial elbow débridement is a viable surgery in MLB athletes, with RTP rate of 82.1% and no increase in rate of UCL reconstruction. Furthermore, there was no significant difference in single season preoperative and postoperative statistical pitching performance. However, over three years postoperatively, there was a 38.5% rate of return to the DL/IL for ongoing elbow ailment and a significant decrease in pitch velocity, raising some concern over the longevity of postoperative improvements., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Prior to the Major League Baseball (MLB) draft, some pitchers undergo predraft magnetic resonance imaging (MRI). This study aimed to evaluate pre-draft elbow MRI on baseball pitchers who were entering the MLB draft to determine the presence or absence of pathology, the associations between these pathologies and ulnar collateral ligament (UCL) tears, and interobserver reliability regarding common MRI pathology., Methods: Predraft elbow MRI performed on prospective MLB pitchers between 2011 and 2017 were deidentified and then reviewed by two separate authors. The authors graded the MRI on several factors including presence or absence of: UCL ossification, UCL appearance (heterogeneous or not), UCL thickening (and location), UCL tear (partial vs. full thickness and location), muscle strain, flexor tendon tear, posteromedial osteophyte, sublime tubercle enthesophyte, and osseous stress reactions., Results: Overall, 245 predraft elbow MRI were reviewed. MRI abnormalities were found in 70% (171/245) of pitchers. UCL thickening was found in 20% (50/245) of pitchers. Regarding UCL tears, 3% had a full thickness tear and 24% had a partial thickness tear. Of full thickness tears, 86% were distal and 1 was midsubstance. Of partial thickness tears, 41% (24/58) were distal, 12% (7/58) were midsubstance, and 47% (27/58) were proximal. Periligamentous edema was present in 36% of pitchers while 14% had a flexor pronator muscle strain., Conclusion: The majority (70%) of pitchers entering the MLB draft had abnormal findings on their MRI, most commonly involving changes to the UCL. Interobserver reliability was acceptable following the definition of pathology when reading predraft elbow MRI on MLB prospects., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Shoulder and elbow pain are the common complaints associated with throwing injuries in baseball players. Prospective studies evaluating the effectiveness of stretching in increasing posterior shoulder flexibility or strengthening the external rotator muscles as preventive strategies for throwing injuries in baseball players have been published. However, there are limited reviews highlighting the role of preventive interventions for throwing injuries in baseball players. Therefore, this scoping review aimed to summarize the existing literature on preventive interventions for throwing injuries in baseball players., Methods: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Scopus databases on 3 March 2023. Two independent reviewers screened the studies based on the eligibility criteria. We extracted existing literature on preventive interventions and effectiveness for throwing injuries in baseball players, and participants' characteristics and results were extracted from the studies. This scoping review was performed in accordance with the Extended Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement for Scoping Reviews., Results: The initial database search yielded 1170 articles, four of which met the eligibility criteria. Of the included studies, two were randomized controlled trials, and the remaining two were prospective cohort studies. Eligible studies targeted youth-to high school-level players and focused on preventive programs for throwing injuries that manifest in the upper extremities of baseball players. The outcome measure most commonly used to quantify the effectiveness of prevention programs was the incidence of shoulder and elbow injuries, although the definitions vary among studies. The prevention program included sleeper stretching, shoulder external rotation strengthening exercises, and comprehensive prevention programs (focusing on improving the elbow, shoulder, and hip range of motion; rotator cuff and periscapular muscle strength; posture; and lower extremity balance). Each prevention program was reported to have the potential to reduce the incidence of throwing injuries in baseball players, and two studies suggested that high compliance with the program led to a lower injury risk., Conclusion: This scoping review confirmed the presence of studies that examined preventive interventions for throwing injuries in baseball players. Preventive interventions that may reduce throwing injuries in baseball players include sleeper stretching, shoulder external rotation strengthening exercises, and comprehensive prevention programs. However, the characteristics of participants (eg, age, sports level, and position) and the definition of injury varied among previous studies. Injury profiles and prevention strategies may differ according to age, sport level, and position of players, and more studies are needed to prove this issue., (Copyright © 2024 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Ulnar collateral ligament (UCL) injuries are a source of significant injury among baseball players, and are increasingly evaluated under ultrasound. The purpose of this study is to determine the effect of a single session of pitching upon UCL thickness and laxity via a cross sectional, controlled ultrasonographic study. We hypothesize that a single session of pitching will cause the ulnar collateral ligament to thicken and become more lax., Methods: This was a cross sectional comparative study of collegiate and high school pitchers. Pitchers underwent an ultrasonographic assessment of the UCL before and after a thirty-pitch bullpen warm-up. Laxity was measured as the change in the distance between the ulna and the trochlea with and without a 5-pound weight held in hand with the elbow at 30° of flexion. Pre- and post-throwing UCL thickness and medial laxity were statistically compared with paired tests., Results: Our study included 15 pitchers, 8 collegiate and 7 high school level athletes. All played baseball at least 6 days a week, and nearly all played for at least 10 months a year. Pitchers reported a peak velocity of 89 ± 6 (77 to 98) miles per hour. In the prior season, these pitchers pitched 56 ± 33 (10 to 120) games, throwing 62 ± 34 (25-140) pitches per game on average. After throwing, there was significantly less UCL laxity (P = .013). Post-throwing laxity was significantly positively correlated with both peak pitch velocity (P = .009) and an average number of pitches thrown per game (P = .10)., Conclusion: Throwing 30 pitches significantly decreases medial elbow laxity with stress, possibly due to flexor-pronator activation. Post-throwing medial laxity is correlated with both peak pitch velocity and average number of pitches thrown per game. Future studies should be conducted to determine the number of throws at which laxity begins to increase, as this may provide a workload management guideline for injury prevention., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: In baseball players with elbow injuries, towel drills are clinically used before initiating active throwing exercises to gradually increase stress across the elbow. However, elbow valgus torque during towel drills remains unknown. Moreover, towel drills and active ball throws might have different relationships between biomechanical metrics, such as elbow stress, arm slot, and arm speed. Therefore, the aims of this study were 1) to demonstrate the difference in elbow valgus stress between towel drills and active ball throws and 2) to evaluate the correlation between elbow valgus torque and other biomechanical metrics including arm slot and arm speed in towel drills and active ball throws., Methods: Seventeen healthy college baseball players performed three towel drills using a face towel, short foam tube, and long foam tube, followed by full-effort throwing on flat ground. Each participant completed five consecutive trials of each task, and the elbow valgus torque, arm slot, and arm speed were measured using wearable sensors. One-way repeated analysis of variance and post-hoc tests were used to determine the differences in biomechanical metrics among the tasks. Furthermore, the correlation between the elbow valgus torque and other metrics was evaluated using Pearson correlation coefficients., Results: Elbow valgus torque was lower in towel drills compared to that of active ball throws; however, the stress during towel drills using a face towel reached almost 80% of the maximum effort of active ball throws. There was no relationship between elbow valgus stress and arm slot in either the towel or active ball throw tasks. However, a higher arm speed was associated with greater elbow valgus torque in towel drills, whereas no relationship between elbow stress and arm speed was found in active ball throws., Conclusion: Precaution must be taken in athletes following a progressive throwing program because elbow valgus stress reaches almost 80% of the full-effort throw, even when using a face towel in a towel drill. Hence, the subjective intensity must be controlled even in towel drills to gradually increase the medial elbow stress. Moreover, the mechanisms underlying changes in elbow stress may differ between towel drills and active ball throws. Future investigations on the difference between towel drills and active ball throws may help understand the underlying mechanism of alterations in elbow valgus torque during the throwing movement., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

The lateral elbow is subjected to increasing compressive force in response to repetitive valgus stress. Alterations or deficiencies in overhead mechanics and the kinetic chain may predispose an athlete to injury. Evaluation includes a focused elbow physical examination and imaging, supplemented by a robust screening of core strength, balance, and mechanics of the kinetic chain. Treatment of osteochondritis dissecans, a common lateral elbow pathology, varies based on stability of the lesion, with variable, but often positive outcomes. Proper pitching mechanics, kinetic chain integrity, and workload management provide potential opportunities for prevention., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: As overhead sports continue to grow in popularity, there has been increased interest in optimizing sports performance and injury prevention in these athletes. The hip, core, and kinetic chain have become a focus of research in recent decades, and their importance in upper extremity mechanics is now being recognized., Methods: An extensive review was carried out to identify papers correlating the hip, core and/or kinetic chain in overhead athletic performance and injury., Results: Recent literature has shown that efficiency and synchrony of the hips and core during an overhead movement (such as in baseball, golf, tennis, or volleyball) is essential for a powerful and precise execution of the task. Impairments of the hip and core, particularly abnormal joint mobility or weakness, can limit efficient energy transfer through the kinetic chain and may negatively impact performance. Recent epidemiologic studies have found hip pain to be common in adolescent, collegiate, and adult athletes. Moreover, hip pain in overhead athletes specifically has also been found to occur at a high rate. Abnormalities in hip range of motion, hip morphology, and core strength can lead to abnormal mechanics upstream in the kinetic chain, which may place athletes at risk of injuries., Conclusion: In this review, the complex and multifaceted relationship between the hip, core, and kinetic chain is highlighted with an emphasis on recent literature and relevant findings., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

There has been an epidemic increase in injuries to the elbow in our youth sports over the past 15 years. Initially, career-ending elbow injuries occurred almost exclusively in the professional population. The landmark procedure developed by Dr. Frank Jobe, colloquially termed "Tommy John surgery" after the initial player in whom he performed the surgical procedure, allowed roughly two-thirds of professional athletes to return to play at or near the same level. As the surgical procedure became more widespread, modifications of the technique by Jobe and many other contributors raised the return-to-play level to 85%-94% of players regaining the ability to return to sport at the preinjury level. Almost simultaneously, the emphasis on velocity in the professional ranks led to an unintentional increase in stress on the throwing elbow. This was magnified in our athletes by the advent of year-round sports, as well as the formation of "showcase" events to demonstrate skills and measure velocity. This, unfortunately, has resulted in an increase in both repetitive stress injuries and acute traumatic injuries in our young athletes. The purpose of this article is to discuss age-related injuries from both a preventative standpoint and a treatment standpoint., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Although lateral elbow pain and medial ulnar collateral ligament injury are common musculoskeletal pathologies in overhead athletes, the evidence supporting specific interventions for managing these conditions is scarce. Management of these conditions has been guided mostly by expert opinion rather than empirical evidence, yet the lack of comparative data in the literature has not negatively affected return-to-play rates following surgery. However, an understanding of what is known regarding unimodal and multimodal treatments for lateral elbow pain and medial ulnar collateral ligament injury is needed for clinicians to select evidence-based treatment pathways and highlight what is not known to develop future high-quality investigations., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Subscapularis muscle strains can develop in professional baseball players, rendering the players unable to continue playing for a certain period. However, the characteristics of this injury are not well known. The purpose of the present study was to investigate the details of the injury and the postinjury course of subscapularis muscle strain in professional baseball players., Methods: Of 191 players (83 fielders and 108 pitchers) who were members of a single Japanese professional baseball team between January 2013 and December 2022, 8 players (4.2%) had subscapularis muscle strain and were enrolled in this study. The diagnosis of muscle strain was made on the basis of shoulder pain and magnetic resonance imaging findings. The incidence of subscapularis muscle strain, the details of the site of the injury, and the time to return to play were examined., Results: Subscapularis muscle strain occurred in 3 (3.6%) of 83 fielders and 5 (4.6%) of 108 pitchers, with no significant difference between fielders and pitchers. All players had injuries on the dominant side. Most injuries were located at the myotendinous junction and in the inferior half of the subscapularis muscle. The mean time to return to play was 55.3 ± 40.0 (range, 7-120) days. At a mean 22.7 months after the injury, there were no reinjured players., Conclusion: A subscapularis muscle strain is a rare injury among baseball players, but in players whose shoulder pain cannot be given a definite diagnosis, subscapularis muscle strain should be considered as a possible etiology., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Ulnar collateral ligament (UCL) tears are common in baseball players. Although magnetic resonance imaging (MRI) is the most used imaging modality for UCL injuries, the inter-rater reliability of MRI analyzing specific characteristics of UCL pathology has not been defined. The purpose of this study was to define the inter-rater reliability of MRI for evaluating UCL characteristics., Methods: Three surgeons analyzed 45 noncontrast MRIs: 15 without UCL tears, 15 with intraoperatively confirmed partial-thickness tears, and 15 with intraoperatively confirmed full-thickness tears. Findings evaluated included ligament characteristics (periligamentous or osseous edema, ligament hypertrophy, calcifications, and partial- or full-thickness tearing) and location of the pathology (proximal, midsubstance, or distal). Fleiss' κ coefficients were used to assess interobserver reliability., Results: There were high rates of agreement for midsubstance (κ: 0.50) and distal (κ: 0.69) ligament edema and proximal osseous edema (κ: 0.48). There were low rates of agreement for proximal ligament edema (κ: 0.08), ligament thickening (κ: -0.02 to 0.20), and proximal to midsubstance calcifications (κ: -0.04 to 0.10). Midsubstance (κ: 0.55) and distal full-thickness tears (κ: 0.63) demonstrated higher agreement than proximal (κ: 0.29). Proximal partial-thickness tears (κ: 0.45) had higher agreement than midsubstance (κ: -0.02) or distal (κ: -0.02)., Conclusions: In our study, there was high inter-rater reliability regarding proximal osseous edema, midsubstance, and distal ligament edema and full-thickness tears. There was no agreement for midsubstance and distal partial-thickness UCL tears, but fair agreement for proximal tears. UCL tissue characteristics including ligament thickening and calcifications demonstrated low agreement. Challenges remain in effectively evaluating UCL tissue characteristics on noncontrast MRIs., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Baseball pitching induces a large elbow valgus load, stressing the ulnar collateral ligament (UCL). Flexor-pronator mass (FPM) contraction contributes to valgus stability; however, repetitive baseball pitching may weaken the FPM contractile function. The present study investigated the effects of repetitive baseball pitching on the medial valgus stability measured using ultrasonography. We hypothesized that repetitive pitching would decrease elbow valgus stability., Methods: This was a controlled laboratory study. Fifteen young male baseball players at the collegiate level (age: 23.0 ± 1.4 years) were enrolled. The medial elbow joint space was measured using ultrasonography (B-mode, 12-MHz linear array transducer) in the following three conditions: at rest (unloaded), under 3 kg valgus load (loaded), and under valgus load with maximal grip contraction to activate FPM (loaded-contracted). All measurements were performed before and after the pitching tasks, which comprised five sets of 20 pitches. Two-way repeated-measures analysis of variance was applied to determine changes in the medial elbow joint space. The post hoc test with Bonferroni adjustment was applied to assess the changes within the time and condition., Results: The medial elbow joint space was significantly greater under the loaded than the unloaded and loaded-contracted conditions both before and after pitching (P < .001). In the loaded-contracted condition, the medial elbow joint space significantly increased after repetitive baseball pitching (P < .001)., Conclusions: The results of the present study indicated that repetitive baseball pitching reduced the elbow valgus stability. This reduction could be attributed to the decreased FPM contractile function. Insufficient contraction may increase the tensile load on the UCL with pitching. FPM contraction plays a role in narrowing the medial elbow joint space; however, repetitive baseball pitching reduced the elbow valgus stability. It has been suggested that sufficient rest and recovery of the FPM function are required to reduce the UCL injury risk., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Few studies have retrospectively analyzed the relationship between joint range of motion (ROM) and muscle flexibility and shoulder and elbow throwing injuries in a large number of elementary school baseball players. The purpose of this study was to retrospectively identify the physical factors related to shoulder and elbow throwing injuries in younger baseball players., Methods: A total of 2466 younger baseball players belonging to our Prefecture Rubber Baseball Federation who participated in medical check-ups from 2016 to 2019 were analyzed. Players completed a questionnaire and had a medical check-up that included a physical examination and ultrasonography. ROM (internal rotation [IR] angle and external rotation angle) of the shoulder and hip and the finger-to-floor distance and heel-to-buttock distance were measured. The straight leg raise was also performed. The results of two groups (normal group and injury group) were compared using the χ 2 test, Mann-Whitney U test, and Student t test. Stepwise forward logistic regression models were developed to identify risk factors., Results: On univariate analysis, nine of the 13 evaluated items showed significant decreases in ROM and muscle flexibility in the injury group. On multiple logistic regression analysis, grade, finger-to-floor distance, IR angle of the dominant side shoulder, and IR angle of the nondominant side hip were significantly associated with the occurrence of throwing injuries. Decreased total shoulder angle was observed not only on the dominant side but also on the nondominant side in the injury group., Conclusion: Decreased ROM and muscle flexibility were risk factors for baseball-related throwing injuries in elementary school baseball players. To prevent shoulder and elbow throwing injuries, players, coaches, medical staff, and parents need to be aware of these findings., (Copyright © 2023. Published by Elsevier Inc.)

Background: Recent evidence indicates that combined upper extremity blood flow restriction (BFR, applied distally to the shoulder) and low-load resistance exercise (LIX) augments clinically meaningful responses in shoulder region tissues proximal to the occlusion site. The purpose of this investigation was to determine the efficacy of BFR-LIX for the shoulder when added to standard offseason training in Division IA collegiate baseball pitchers. We hypothesized that BFR-LIX would augment training-induced increases in shoulder-region lean mass, rotator cuff strength, and endurance. As secondary outcomes, we sought to explore the impact of BFR-LIX rotator cuff training on pitching mechanics., Methods: Twenty-eight collegiate baseball pitchers were randomized into 2 groups (BFR N = 15 and non-BFR [NOBFR] N = 13 ) that, in conjunction with offseason training, performed 8 weeks of shoulder LIX (Throwing arm only; 2/week, 4 sets [30/15/15/fatigue], 20% isometric max) using 4 exercises (cable external and internal rotation [ER/IR], dumbbell scaption, and side-lying dumbbell ER). The BFR group also trained with an automated tourniquet on the proximal arm (50% occlusion). Regional lean mass (dual-energy x-ray absorptiometry), rotator cuff strength (dynamometry: IR 0 & 90, ° ER 0 & 90, ° Scaption, Flexion), and fastball biomechanics were assessed pre and post-training. Achievable workload (sets × reps × resistance) was also recorded. An ANCOVA (covaried on baseline measures) repeated on training timepoint was used to detect within-group and between-group differences in outcome measures (α = 0.05). For significant pairwise comparisons, effect size (ES) was calculated using a Cohen's d statistic and interpreted as: 0-0.1, negligible; 0.1-0.3, small; 0.3-0.5, moderate; 0.5-0.7, large; >0.7, and very large (VL)., Results: Following training, the BFR group experienced greater increases in shoulder-region lean mass (BFR: ↑ 227 ± 60g, NOBFR: ↑ 75 ± 37g, P = .018, ES = 1.0 VL) and isometric strength for IR 90 ° (↑ 2.4 ± 2.3 kg, P = .041, ES = 0.9VL). The NOBFR group experienced decreased shoulder flexion ↓ 1.6 ± 0.8 kg, P = .007, ES = 1.4VL) and IR at 0 ° ↓ 2.9 ± 1.5 kg, P = .004, ES = 1.1VL). The BFR group had a greater increase in achievable workload for the scaption exercise (BFR: ↑ 190 ± 3.2 kg, NOBFR: ↑ 90 ± 3.3 kg, P = .005, ES = 0.8VL). Only the NOBFR group was observed to experience changes in pitching mechanics following training with increased shoulder external rotation at lead foot contact (↑ 9.0° ± 7.9, P = .028, ES = 0.8VL) as well as reduced forward ↓ 3.6° ± 2.1, P = .001, ES = 1.2VL) and lateral ↓ 4.6° ± 3.4, P = .007, ES = 1.0VL) trunk tilt at ball release., Conclusion: BFR-LIX rotator cuff training performed in conjunction with a collegiate offseason program augments increases in shoulder lean mass as well as muscular endurance while maintaining rotator cuff strength and possibly pitching mechanics in a manner that may contribute to favorable outcomes and injury prevention in baseball pitching athletes., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Arm injuries are commonly encountered in baseball as young athletes play into adulthood. The purpose of this study was to examine the incidence of arm injury and risk for surgery in adolescent baseball players followed over a 10-year period from scholastic, age-group, and travel baseball leagues through their highest level of competition., Methods: A prospective study was conducted enrolling middle and high school baseball players in 2010-2012, then followed for 10 years or until retirement from competitive baseball. Players were included if fully participating in team activities at the time of preseason study enrollment. Players with prior arm (shoulder or elbow) surgery or those diagnosed with time loss arm injury within the past year were excluded. Only shoulder and elbow overuse problems resulting in time-loss from sport and medical attention from a sports medicine physician or orthopedic surgeon were documented as injuries in this study. Musculoskeletal overuse injuries were classified based on the orchard injury classification system. Incidence proportion and risk ratio (RR) and 95% confidence intervals (CIs) for initial injury and injuries requiring surgery were calculated., Results: A total of 261 pitchers (age: 14.2 ± 2.6 years; follow-up: 4.2 ± 2.7 years) were enrolled. Twenty percent of the cohort was followed for ≥7 years. The overall injury incidence was 25.6/100 athletes (95% CI 21-31) with a cumulative surgical incidence of 5.4/100 athletes (95% CI 3.2-8.8). The risk of experiencing shoulder injury (n = 25) and elbow injury (n = 38) were similar (n = 38) (RR 0.7, 95% CI 0.4-1.1). The athletes also presented with a similar frequency of requiring surgery regardless of the injured body part. However, the risk of surgery in those playing beyond the high school level was 4.3 times greater (95% CI 1.2-15.0) than those only playing high school., Conclusion: This is the first study to follow a large cohort of youth baseball players as they progress, showing a relatively high arm injury incidence. Shoulder and elbow injury incidence was similar but surgical risk increased playing beyond high school, specifically for the elbow. The high injury frequency and burden of care required by young baseball players as reported in this study is concerning, and strategies to reduce injury should be investigated., (Copyright © 2023 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background and Hypothesis: Despite successful return-to-sport (RTS) outcomes after posteromedial osteophyte resection, one possible consequence of osteophyte removal is increased stress on the ulnar collateral ligament (UCL), leading to a UCL injury. It is currently unknown how often overhead athletes who undergo isolated posteromedial osteophyte resection subsequently require UCL reconstruction (UCLR). Therefore, the purpose of this study was to report outcomes following arthroscopic resection of posteromedial osteophytes in overhead athletes and determine whether overhead athletes who underwent arthroscopic posteromedial osteophyte resection for posteromedial impingement went on to require UCL surgery. We hypothesized that there would be a high rate of RTS following osteophyte resection and that players who underwent arthroscopic posteromedial osteophyte resection would have a >10% risk of requiring subsequent UCLR or UCL repair., Materials and Methods: All patients who underwent elbow arthroscopy from 2010-2020 at a single institution were reviewed. Patients were included if they underwent isolated arthroscopic posteromedial osteophyte resection without concomitant UCL surgery, were overhead athletes at the onset of posteromedial impingement symptoms, and had no history of elbow surgery. Primary outcomes included RTS rate, complications, and subsequent shoulder and/or elbow injury and surgery, as well as several patient-reported outcome measures (Kerlan-Jobe Orthopaedic Clinic score, Timmerman-Andrews elbow score, and Conway-Jobe score)., Results: Overall, 36 overhead athletes were evaluated at 5.1 ± 3.4 years postoperatively, including 28 baseball pitchers, 3 baseball catchers, 3 softball players, 1 tennis player, and 1 volleyball player. Of the overhead athletes, 77% were able to RTS; the mean Kerlan-Jobe Orthopaedic Clinic and satisfaction scores were 70 and 75, respectively; and 89% of athletes had either excellent (73%) or good (16%) Conway-Jobe scores at long-term follow-up. Subsequent UCLR was required in 18% of baseball pitchers (n = 5) at a median of 13 months postoperatively. Of the 5 UCLRs, 3 were performed shortly after posteromedial osteophyte resection (6, 7, and 13 months postoperatively) whereas the other 2 were performed at 6.2 and 7.5 years postoperatively., Conclusion: Following arthroscopic posteromedial osteophyte resection, 77% of athletes were able to RTS. Baseball pitchers who undergo arthroscopic resection of posteromedial osteophytes for posteromedial impingement have an 18% risk of subsequent UCLR., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Excessive elbow valgus stress can often cause pitching elbow injuries, and rehabilitation is usually required before an athlete can resume playing. However, there is a lack of information on the partial load rehabilitation of pitching elbow injuries caused by valgus extension overload based on elbow valgus stress. The purpose of this study was to clarify how quantitative partial elbow valgus stress while pitching affects ball velocity and subjective pitch-effort., Methods: Forty-six male baseball pitchers participated in this study. Each player wore a wearable device on the elbow that collected their pitch parameters. Ball velocity was measured using a radar gun. Each elbow valgus stress was measured while each player was instructed to throw 5 fastballs at full effort. Then, based on the average stress of the 5 throws (100% partial valgus stress), the 75% and 50% stresses were calculated (75% and 50% partial valgus stress, respectively). Each pitcher continued to pitch until the number of pitches thrown at the targeted elbow stress reached 5. Each player was asked about their subjective pitch-effort after completing each type of partial valgus stress pitch. Outcomes were statistically evaluated using either a 1-way repeated measures analysis of variance or 2-way analysis of variance., Results: The ball velocity was 72% (95% confidence interval [CI], 69%-75%) and 58% (95% CI, 55%-61%) during the 75% and 50% partial valgus stress, respectively (P < .001). Subjective pitch-effort was 41% (95% CI, 38%-44%) and 19% (95% CI, 16%-22%) while pitching at 75% and 50% partial valgus stress, respectively (P < .001)., Conclusions: It may be desirable to instruct pitchers to throw at less than 20% subjective pitch-effort of the max if they want to pitch at 50% partial valgus stress. Elbow valgus stress might correlate with ball velocity at 75% partial valgus stress pitch. These results could enable clinicians and coaches to perform safer return-to-throwing programs and prevent excessive load on the elbow., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Adolescent baseball players with a history of medial elbow injury are often reinjured during demanding practice sessions or games. The physical characteristics of baseball players with a history of medial elbow injury have been reported in several previous studies, but the nature of their medial elbow stabilizers is unknown. This study investigated the difference in characteristics of elbow valgus laxity and medial elbow stabilizer parameters between baseball players with and without a history of medial elbow injury, prior to and during repetitive pitching., Methods: Sixteen high school baseball players with no history of medial elbow injury (No-Injury group) and 14 high school baseball players with a history of medial elbow injury (Injury History group) participated. The participants pitched 100 fastballs. Medial elbow joint-space gapping and strain ratio indicating tissue elasticity of ulnar collateral ligament (UCL) and forearm flexor-pronator muscles (FPMs) were measured by ultrasound before pitching and following each of five 20-pitch blocks. Student t tests and Mann-Whitney U tests were used to compare each parameter between groups., Results: Medial elbow joint-space gapping and UCL elasticity were not significantly different between the 2 groups in each pitching block (P > .05). The strain ratio of FPMs before pitching and after 100 pitches in the Injury History group were significantly greater than that in the No-Injury group (No-Injury vs. Injury History group: before pitching, 0.47 ± 0.19 vs. 0.68 ± 0.26, P = .016; 100 pitches, 0.35 ± 0.12 vs. 0.53 ± 0.20, P = .007). In the other pitching blocks, there was no significant difference between groups, but the effect size was medium and showed a similar tendency (20 pitches, P = .069, Cohen d = 0.69; 40 pitches, P = .116, Cohen d = 0.59; 60 pitches, P = .102, Cohen d = 0.62; 80 pitches, P = .058, Cohen d = 0.72)., Conclusions: The results of this study indicate that FPM elasticity at baseline and during repetitive pitching in players with a history of medial elbow injury was harder than in players without injury history. This may suggest that baseball players with a history of medial elbow injury increase support of their previously injured medial elbow by hardening FPM elasticity to counteract elbow valgus stress generated during pitching, which may lead to long-term change in the FPMs. Therefore, physical management for this change may be important to prevent reinjury in baseball players with a history of medial elbow injury., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Currently, there are few studies that have evaluated the relationship between a lower extremity or trunk injury (kinematic chain) and subsequent arm injury. The purpose of this study was (1) to investigate the relationship between initial kinematic chain (lower extremity or trunk) injury and subsequent arm injury; and (2) to investigate the relationship between initial shoulder or elbow injury and subsequent arm injury., Methods: A 7-year prospective injury risk study was conducted with Minor League Baseball pitchers. Pitches, pitching appearances, athlete exposures (AEs), and arm injuries (≥1-day time loss) were documented throughout the season. Cox survival analyses with 95% confidence intervals (95% CIs) were performed. Confounders controlled for included age, body mass index, arm dominance, pitching role, previous arm injury, number of pitching appearances, and seasonal pitch load., Results: A total of 297 pitchers participated (total player days = 85,270). Arm injury incidence was 11.4 arm injuries/10,000 AEs, and kinematic chain incidence was 5.2 injuries/10,000 AEs. Pitchers who sustained a kinematic chain injury demonstrated a greater hazard (2.6 [95% CI: 1.2, 5.6], P = .019) of sustaining an arm injury. Pitchers who sustained an initial shoulder injury demonstrated a greater hazard (9.3 [95% CI: 1.1, 83], P = .047) of sustaining a subsequent shoulder or elbow injury compared with pitchers who sustained an initial elbow injury., Conclusions: Pitchers who sustained an initial lower extremity or trunk injury demonstrated an increased subsequent arm injury hazard compared with pitchers who did not. Pitchers who sustained an initial shoulder injury demonstrated a greater hazard of sustaining a subsequent arm injury compared with pitchers who sustained an initial elbow injury. However, this secondary analysis should be interpreted with caution. Clinicians should monitor risk with workload accumulation, which may be related to pitching compensatory strategies in a fatigued state. Pitchers who sustain a shoulder injury should be evaluated and perform both shoulder and elbow rehabilitation strategies before return to sport., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Ulnar collateral ligament (UCL) and flexor-pronator muscle (FPM) injuries are common in baseball players. However, the sites of FPM injuries and the relationship between UCL and FPM injuries in baseball players have not been fully clarified. The purpose of this study was to identify the sites of FPM injuries and to determine the relationships of location and severity of UCL injury with the presence of FPM injuries in baseball players., Methods: UCL and FPM injuries were diagnosed using magnetic resonance imaging in 99 baseball players. The sites of FPM injuries were identified on coronal, sagittal, and axial images. UCL injury severity was classified into four grades: chronic changes, low-grade partial tear, high-grade partial tear, and complete tear. UCL injury location was classified as proximal UCL tear or distal UCL tear. All images were assessed by a musculoskeletal radiologist and an orthopedic surgeon., Results: Combined UCL and FPM injuries were observed in 45 of 99 players, of which 40 of 45 (89%) involved injury of the flexor digitorum superficialis (FDS). All FDS injuries were in the deep layer of the muscle belly. There was no significant difference between the severity of UCL injury and presence of FPM injuries (P = .352). There was a significant association of distal UCL tears with FPM injuries (P < .001)., Conclusion: FDS injury occurs most commonly in the muscle belly of the second and fifth digits. There may be no relationship between the severity of UCL injury and presence of FPM injury in baseball players. FPM injuries may be a contributing factor in the failure of nonoperative management of distal UCL tears in baseball players., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Posterior shoulder capsule tightness is one of the factors for shoulder injuries in overhead athletes. Recent studies have shown the posterior capsule of the dominant arm to be stiffer than that of the nondominant arm in baseball players. However, whether posterior capsule tightness in the dominant arm is exclusive to overhead athletes remains unknown. This study aimed to investigate whether the posterior shoulder capsule of the dominant arm in baseball players is stiffer than that in nonthrowing population., Methods: Fifteen male collegiate asymptomatic baseball players (baseball-player group) and fifteen male college students who did not partake in overhead sports (nonthrowing group) participated in this study. We measured the shear moduli of the middle and inferior posterior capsules, superior infraspinatus, inferior infraspinatus, teres minor, and posterior deltoid in the dominant arm by ultrasound shear wave elastography. We compared shear moduli between the two groups using an independent samples t-test and Mann-Whitney test. In addition, we investigated the correlation between the range of glenohumeral internal rotation and each shear modulus in each group using the Pearson correlation coefficient., Results: The shear moduli in the baseball-player group were significantly higher than those in the nonthrowing group in both the middle posterior capsule (baseball-player group: 36.1 ± 5.6 kPa vs. nonthrowing group: 29.0 ± 8.6 kPa; P = .018) and inferior posterior capsule (37.1 ± 9.6 kPa vs. 27.9 ± 6.8 kPa; P = .002). However, no difference in the shear moduli of individual muscle groups was identified. The glenohumeral internal rotation range exhibited a statistically significant negative correlation with the shear modulus of the inferior posterior capsule in the baseball-player group (Pearson correlation coefficient = -0.586, P = .022)., Conclusion: Our findings suggest that the posterior shoulder capsule of the dominant arm in baseball players is stiffer than that in nonthrowing population., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Medial ulnar collateral ligament (UCL) injuries and posterior elbow impingement commonly affect throwing athletes. Surgical intervention for each of these pathologies individually has been demonstrated to be successful with high return-to-play (RTP) rates. Our purpose was to report RTP rates for patients treated with concurrent UCL reconstruction (UCLR) and arthroscopic posterior débridement performed by the senior author., Materials and Methods: We retrospectively reviewed all elbow medial UCL procedures performed by the senior author from January 2016 through September 2020. The inclusion criteria included an elbow medial UCL operation with arthroscopic posterior-compartment débridement in a throwing athlete. The exclusion criteria included isolated UCLR surgery, non-primary surgery, and revision UCLR with either autograft or allograft. Using a chart review and publicly available information, we were able to determine patients' playing levels after their operations., Results: Twelve patients met the inclusion and exclusion criteria. The average age was 24.27 years (standard deviation, 4.92 years). Of the 12 patients, 10 returned to play at the same level (4 Major League Baseball players and 1 Triple A player) or at a higher level (2 players from Single A to Double A, 1 player from National Collegiate Athletic Association Division I to Single A, 1 player from rookie league to Single A, and 1 player from high school to National Collegiate Athletic Association Division I), 1 did not return to play, and 1 returned to play at a lower level, with an average RTP time of 14.64 months (standard deviation, 2.64 months). Of the 12 patients, 11 were pitchers; of these 11 pitchers, 9 had statistics available both before and after UCLR. Before UCLR, the average statistics for the pitchers were as follows: earned run average, 4.11 ± 0.85; walks and hits per inning pitched, 1.42 ± 0.26; strikeout-to-walk ratio, 3.00 ± 1.83; strikeouts per 9 innings, 8.80 ± 1.14; and innings pitched, 234.88 ± 316.74. After UCLR, their average statistics were as follows: earned run average, 5.24 ± 2.18 (P = .189); walks and hits per inning pitched, 1.55 ± 0.34 (P = .379); strikeout-to-walk ratio, 2.15 ± 0.98 (P = .263); strikeouts per 9 innings, 9.67 ± 1.91 (P = .293); and innings pitched, 138.71 ± 162.97 (P = .487)., Discussion and Conclusion: Although surgical intervention to address both posterior impingement and UCL injury is relatively rare (comprising 8.5% of all the senior author's UCLR procedures), our experience demonstrates that primary UCLR with concurrent arthroscopic posterior decompression is a reliable, safe, and successful surgical treatment for patients with UCL injury and posterior impingement and our results show no significant difference in statistical performance in pitchers before surgery vs. after surgery., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background and Hypothesis: Early trunk rotation (ETR), which is a unique kinematics of the trunk that occurs during baseball throwing, is thought to be related to shoulder injuries. Pelvic rotation is a confounder when studying the effects of trunk rotation on shoulder biomechanics. The purpose of this study was to understand the "pure" effects of trunk rotation on shoulder biomechanics, with pelvic rotation under control. Our hypotheses were as follows: (1) throwers with ETR have a different shoulder kinematics pattern compared with throwers without ETR; (2) throwers with ETR have a lower ball speed performance than do throwers without ETR; and (3) throwers with ETR have a greater value of shoulder forces and moments, which may increase risks of shoulder injury, than do throwers without ETR., Methods: Fifty-seven elite throwers were enrolled and divided into 2 groups (non-ETR and ETR) using an outdoor motion analysis. Several kinematics and kinetics parameters of the shoulder were analyzed and compared between the 2 groups., Results: Ball velocity was faster in the non-ETR group (127 km/h) compared with the ETR group (120 km/h). The shoulders of throwers in the ETR group showed pathokinematics of "horizontal adduction lag" and "dropped elbow." The increases in maximal posterior force, inferior force, horizontal abduction moment, and vertical adduction moment were 9.2%, 13.6%, 21.3%, and 24.3%, respectively, in the shoulders of throwers in the ETR group. These results indicate that ETR may be hazardous for the throwing shoulder. With lower ball velocity and higher shoulder joint loading, ETR is not a proper pitching pattern for kinetic energy transfer., Conclusion: Improper pitching mechanics among baseball throwers, such as ETR, may result in higher shoulder joint loading and increased risk of shoulder injuries. When treating throwers with shoulder injuries, it is important not only to address shoulder anatomy and pathology but also to understand the possible pathomechanics and pathogenesis of the shoulder caused by ETR. Furthermore, special training programs focusing on trunk flexibility and core muscle strengthening should be implemented to prevent ETR and decrease the risk of shoulder injuries. Motion analysis is useful for the screening and early detection of improper pitching mechanics in throwers., (Copyright © 2022 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Temporal variations during the pitch have demonstrated significant impacts on the kinetic chain, and as such, have implications in injury risk., Purpose: To determine the effect of varying chronological orders of maximum joint and segment velocities on ball velocity and upper extremity kinetics., Methods: Professional baseball pitchers (n = 287) were assessed with 3D-motion capture (480 Hz) while pitching. Pitches were categorized into one of the following groups dependent on the first maximum joint or segment velocity achieved out of chronological order in an inferior to superior direction: knee extension (DscK), pelvis rotation (DscP), trunk rotation (DscT), shoulder rotation (DscS), forearm pronation (DscF), and Proper (for pitchers with the correct temporal sequence), and Total Population, for all pitchers. Ten normalized throwing arm kinetic variables were compared among groups. Regression analysis was conducted on the timing of maximum velocities with ball velocity., Results: The majority of pitches were in the DscK group (64.5%). The DscK group had a significantly slower maximum lead knee extension velocity compared with the Proper group (253°/s vs. 316°/s, P = .017). The Proper group had a significantly faster ball velocity compared with the Total Population (39.0 ± 1.9 m/s vs. 38.3 ± 2.1 m/s, P = .013). The DscP group had a significantly slower maximum pelvis rotation velocity compared with the Proper group (596°/s vs. 698°/s, P < .001). The Proper group had no significant difference in kinetics relative to the population. For every 1 standard deviation delay in attaining maximum lead knee extension velocity, ball velocity increased by 0.38 m/s (B = 3.5, β = 0.18, P < .001). For every 1 standard deviation delay in timing to achieve maximum pelvis rotation velocity, maximum pelvis rotation velocity and ball velocity increased by 22.5°/s (B = 1107.0, β = 0.23, P < .001) and 0.48 m/s (B = 23.4, β = 0.23, P < .001), respectively., Conclusion: Pitchers with a discordant sequence of knee extension and pelvis rotation velocity timing had significantly slower corresponding segment/joint velocities. Conversely, pitchers with a proper sequence had the fastest ball velocity with minimal differences in throwing arm kinetics. To maximize ball velocity, professional pitchers should consider achieving maximal velocities in an inferior to superior chronological sequence, with a particular focus on the knee and pelvis., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The baseball pitching motion creates valgus stress to the medial elbow, which contributes to increased medial elbow joint space gapping. The musculoskeletal systems of preadolescent baseball players are immature compared with those of adults, but it is unclear whether the repetitive pitching action causes an increase in medial elbow joint space gapping. This study aimed to examine differences in medial elbow joint space gapping based on the pitch count of preadolescent baseball players compared with those of adult players., Methods: The participants were 11 healthy preadolescent baseball players and 12 college students with baseball experience. They threw 60 maximal-effort pitches arranged into 4 sets of 15 pitches. The medial elbow joint space was measured ultrasonographically with the forearm weight before pitching and following every set of 15 pitches. Repeated-measures analysis of variance and the Bonferroni post hoc test were used to compare the medial elbow joint space among the 5 pitching sets (before pitching and after 15, 30, 45, and 60 pitches) and between the groups of preadolescent baseball players and college students., Results: There was no significant change in the medial elbow joint space gapping of the dominant elbow based on age/pitch count (F = 0.42, P = .796). There was a significant effect of pitch count (F = 30.28, P < .001) and between-group effects (F = 4.56, P = .045). The medial elbow joint space gapping increased significantly after 60 pitches in preadolescent baseball players (P = .023) and college students (P = .021). The medial elbow joint space gapping in preadolescent baseball players was significantly wider than that in college students (P = .007 before pitching, P = .027 at 15 pitches)., Conclusion: Sixty repetitive pitches contributed to an increase in the medial elbow joint space gapping, regardless of age. The results of this study provide further evidence when considering pitching limitations., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Latissimus dorsi (LD) and teres major (TM) tears have become increasingly recognized injuries in professional baseball pitchers. The purpose of this study was to determine whether workload, as measured by the number of days of rest between outings, number of innings pitched, number of batters faced, and being a starting pitcher, is associated with an increased risk of sustaining an LD-TM tear in professional baseball pitchers., Methods: All professional baseball pitchers who sustained an LD-TM tear between 2011 and 2017 were identified using the Major League Baseball Health and Injury Tracking System. A separate player-usage data set was used to determine workload. We then compared workload variables between pitcher-games 2, 6, 12, and >12 weeks prior to a documented LD-TM tear and pitcher-games from a non-LD-TM tear control group. In a paired analysis, we compared the acute workload (2, 6, and 12 weeks) prior to injury and the injured pitchers' non-acute workload >12 weeks prior to injury., Results: A total of 224 unique LD-TM tears were documented in the Major League Baseball Health and Injury Tracking System database. In most periods, player-games with more innings pitched and more batters faced were associated with a higher incidence of subsequent LD-TM tears. The number of days of rest was not a significant predictor of an LD-TM tear in the acute workload setting, but pitchers who sustained an LD-TM injury averaged fewer days of rest over the previous ≥12 weeks than controls (P < .001). Pitchers who faced >30 batters per game showed a 1.57-fold increase in the percentage of pitchers with a subsequent LD-TM tear as compared with pitchers who faced ≤5 batters per game. Significantly more starting pitchers were in the case group that sustained LD-TM tears over multiple time points than in the control group., Conclusion: Having a greater pitcher workload and being a starting pitcher were associated with an increased risk of sustaining LD-TM tears in professional baseball players. The average number of days of rest was only a risk factor for LD-TM tears over a 3-month or longer period., (Copyright © 2021 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Although results after ulnar collateral ligament reconstruction (UCLR) in baseball players have been well documented, the literature is replete regarding the outcomes after UCLR in javelin throwers., Purpose: To report outcomes after UCLR in javelin throwers., Hypothesis: UCLR in javelin throwers will result in a high rate of return to play similar to that of previously published studies from athletes of other sports., Methods: All patients who were identified preoperatively as javelin throwers and underwent UCLR between 2011 and 2017 with a minimum 2-year follow-up were eligible for inclusion. Patients were assessed with the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow score, Timmerman-Andrews Elbow score, Conway-Jobe score, patient satisfaction, return to sport rate questionnaire, and the occurrence of any postoperative complications., Results: Eighteen patients met the inclusion criteria. Complete follow-up was available in 16 (88.9%) patients. The average age at surgery was 21.2 ± 2.0 (range, 18.6-24.9) years. At the final follow-up, the average Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow score and Timmerman-Andrews Elbow score were 77.3 (range, 18.7-98.4) and 91.8 (range, 70.0-100.0), respectively. Outcomes on the Conway-Jobe scale were as follows: excellent (n = 6; 37.5%), good (n = 4; 25%), fair (n = 6; 37.5%). Ten (62.5%) patients returned to play at an average of 12.2 ± 3.6 (range, 6.0-18.0) months after surgery. Two (12.5%) patients sustained a shoulder injury postoperatively; however, neither required surgery., Conclusion: UCLR in javelin throwers results in good outcomes with a low rate of reinjury/reoperation. However, the return to play rate (62.5%) and good/excellent outcomes per the Conway-Jobe scale (68.8%) are lower than what has been previously reported in baseball players and javelin throwers. Further investigation regarding outcomes in javelin throwers after UCLR is warranted., (Copyright © 2021. Published by Elsevier Inc.)

Background and Hypothesis: Sport specialization is increasingly common in youth sports and is a risk factor for lower-extremity overuse injuries. However, limited data exist on whether specialization is associated with upper-extremity (UE) overuse injuries, specifically in youth baseball players. We hypothesized that specialization in baseball and being a pitcher would be associated with poorer arm health and UE overuse injury history in the previous year., Methods: During the 2019 spring baseball season, 551 high school baseball athletes (aged 15.9 ± 1.3 years) from 3 states (Alabama, n = 200; California, n = 188; and Michigan, n = 163) completed an anonymous questionnaire. Athletes were recruited from 5 high schools in each state, with schools matched based on factors that influence specialization rates. The questionnaire consisted of (1) demographic characteristics, (2) baseball participation information (including sport specialization status), and (3) throwing-arm health and UE injury history in the previous 12 months. Throwing-arm health was assessed using the Youth Throwing Score (YTS), a validated and reliable outcome measure for youth baseball players. Multivariate regression analyses were used to examine the association between variables of interest and the YTS or UE overuse injury history, adjusting for covariates., Results: After adjustment for covariates, highly specialized athletes were more likely to report a UE overuse injury in the previous year compared with low-specialization athletes (odds ratio [OR], 3.77; 95% confidence interval [CI], 1.39-10.2, P = .009). Both athletes who reported playing baseball for more than 8 months per year (OR, 2.03; 95% CI, 1.12-3.65; P = .019) and athletes who reported being a pitcher (OR, 2.11; 95% CI, 1.20-3.72; P = .010) were more likely to report a history of UE overuse injury. Highly specialized players reported lower (worse) YTS values compared with low-specialization players (least-squares mean estimate ± standard error, 56.5 ± 1.1 vs. 53.3 ± 0.7; P = .034). Players who reported pitching as one of their positions scored worse on the YTS than non-pitchers (least-squares mean estimate ± standard error, 51.6 ± 0.8 vs. 57.2 ± 0.6; P < .001)., Conclusion: Although baseball recommendations that discourage sport specialization are widely available for parents, athletes, and coaches, high rates of sport specialization were reported in our sample. We found that being highly specialized in baseball was associated with UE overuse injury history and worse throwing-arm health in high school baseball athletes. Continued education for baseball parents, athletes, and coaches is necessary to raise awareness of the risks associated with high specialization., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Ulnar collateral ligament reconstruction (UCLR) has allowed the return of overhead athletes to throwing sports. We describe a new double suspensory (DS) technique using a single tunnel in the ulna and humerus, achieving fixation with adjustable loop buttons., Methods: Inclusion criteria included skeletally mature baseball players with clinical and magnetic resonance imaging diagnosis of UCL insufficiency who failed a trial of structured nonoperative treatment. A total of 36 baseball players underwent DS UCLR, between 2011 and 2017, by 1 surgeon with minimum 2-year follow-up. The graft was fixated with an adjustable button loop on the humeral side and a tension slide technique with a button on the ulnar side. Pre- and postoperative Kerlan-Jobe Orthopaedic Clinic and Single Assessment Numerical Evaluation and postoperative Conway scores were obtained., Results: The mean age was 19.8 ± 4.6 years (range, 14-35 years). All were male. Mean years played before surgery was 14.3 ± 4.6 years (range, 8-28 years). There were 32 (89%) pitchers and 4 (11%) position players. There were 13 (36%) high school, 20 (55%) college, 2 (6%) minor league, and 1 (3%) adult league athletes. The mean follow-up was 55.3 ± 23.7 months (range, 26-97 months). There was significant improvement in Kerlan-Jobe Orthopaedic Clinic (33.2 ± 19.9 to 89.7 ± 15.1, P < .0001) and Single Assessment Numerical Evaluation (20.7 ± 16.7 to 93.6 ± 11.9, P < .0001) scores. Using Conway scoring, 25 (69%) had excellent, 5 (14%) good, 3 (8%) fair, and 3 (8%) poor scores. Mean return to play was 9 ± 1.5 months (range, 6-16 months). Only 1 (3%) athlete required a revision surgery and ultimately returned to play and 1 (3%) hardware removal. None developed ulnar nerve symptoms., Conclusion: DS fixation for UCLR in baseball players can lead to excellent clinical results and early return to play., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Rehabilitation following elbow ulnar collateral ligament reconstruction in baseball pitchers relies on a progression of pitching activities to ensure protection and gradual strengthening of the reconstructed ligament. The purpose of this study was to determine the medial elbow torque associated with pitches at various effort levels and determine whether radar gun assistance improves players' abilities to accurately match partial-effort pitches with true references based on maximum pitch velocity., Methods: Thirty-seven healthy high school and collegiate baseball pitchers were included in this study. Participants were excluded if they were injured, recovering from injury, or otherwise not currently pitching at full effort. Pitch parameters were collected using a validated wearable sensor. Participants threw 5 pitches at 50%, 75%, and 100% subjective effort. Pitchers then threw 5 pitches at 50% maximum velocity and 75% maximum velocity, as measured by a radar gun., Results: Thirty-seven pitchers completed this study. Pitches thrown at 50% and 75% partial effort were significantly faster and generated higher elbow torque than did pitches thrown at 50% and 75% velocity, respectively (P < .001). A 10% decrease in percentage of maximum velocity was associated with a 13% decrease in percentage of maximum elbow torque (β coefficient = 1.3, R 2 = 0.81, P < .001)., Conclusion: Pitchers generate higher-than-intended forces when throwing at 50% and 75% effort during a subjective partial-effort throwing protocol. Use of a radar gun to guide partial-effort throwing during throwing rehabilitation programs may protect the reconstructed elbow from excess medial torque., (Copyright © 2019. Published by Elsevier Inc.)

Background: Evidence is scarce concerning the relationship of physical dysfunction of the trunk and lower extremities with elbow and shoulder pain in young baseball players. This study aimed to examine the association of joint flexibility of the trunk and lower extremities and dynamic postural control with elbow and shoulder pain among elite young baseball players., Methods: We analyzed baseball players (aged 9-12 years) who participated in the National Junior Sports Clubs Baseball Festival. Range of motion in external rotation and internal rotation (IR) of the hip, as well as the finger-to-floor distance and heel-to-buttock distance, was measured. The straight-leg-raise test was also conducted. Dynamic postural control was evaluated using the Star Excursion Balance Test. Multivariable logistic regression analyses were conducted to examine the association of physical function with the elbow or shoulder pain incidence., Results: Of 210 players surveyed, 177 without elbow or shoulder pain were included in the analysis. Of the participants, 16 (9.0%) reported having elbow or shoulder pain during the tournament. Participants with the incidence of elbow or shoulder pain had a significant restriction in hip IR of the stride leg compared with those without pain (35.8° vs. 43.7°, P = .022). There were no significant associations of other joint flexibilities and the Star Excursion Balance Test with elbow or shoulder pain., Conclusion: Decreased hip IR range of motion of the stride leg was significantly associated with the elbow or shoulder pain incidence. Players, coaches, and clinicians should consider the physical function of the trunk and lower extremities for the prevention of elbow and shoulder pain., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The economic loss following ulnar collateral ligament reconstruction (UCLR) in Major League Baseball (MLB) pitchers has not been evaluated. The purpose of this study is to quantify the financial impact of UCLR on MLB teams. We hypothesize that MLB teams incur significant losses annually as a result of salaries paid to injured players following reconstruction., Methods: Public records were accessed to identify MLB pitchers from January 1, 2004, to December 31, 2014, who had undergone UCLR. Contract terms and time away from competition were used to approximate economic loss. Successful return was considered when a pitcher returned to play in at least 1 Minor League Baseball (MiLB) or MLB game., Results: One hundred ninety-four MLB pitchers underwent UCLR from 2004 to 2014, missing on average 180.2 days of the MLB regular season. Cost of recovery (COR) amounted to $395 million, averaging $1.9 million per player. Starting pitchers accounted for the largest total COR at $239.6 million, whereas closers had the largest economic loss per player ($3.9 million/player). Only 77% of pitchers returned to MLB play., Conclusion: UCLR has a substantial economic impact on MLB teams. Starting pitchers represented a majority of team cost, but closers represented higher costs per pitcher., (Copyright © 2019. Published by Elsevier Inc.)

Background: While many injuries to the rotator cuff in professional baseball players can be managed nonoperatively, recovery fails to occur with nonoperative treatment in some players and surgery on the rotator cuff is performed in an attempt to return to sport (RTS)., Methods: All professional baseball players who underwent rotator cuff surgery between 2010 and 2016 were included by use of the Major League Baseball injury database. Demographic and performance data (before and after surgery) for each player were recorded. Preoperative and postoperative performance metrics were then compared., Results: Overall, 151 professional baseball players underwent rotator cuff débridement (n = 130) or rotator cuff repair (n = 21). In the rotator cuff repair group, 6 (28.6%) underwent single-row repair, 5 (23.8%) underwent double-row repair, and 10 (47.6%) underwent side-to-side repair. Among the 11 players who underwent either single- or double-row repair, the average number of anchors used per repair was 2.09 ± 1.1 (range, 1-4). Most performance metrics declined following rotator cuff débridement. For players who underwent débridement, the RTS rate was 50.8% (42.3% at the same level or a higher level and 8.5% at a lower level). For players who underwent repair, the RTS rate was 33.3% (14.3% at the same level or a higher level and 19% at a lower level). Most players underwent at least 1 concomitant procedure at the time of rotator cuff surgery., Conclusion: Rotator cuff débridement is significantly more common than repair in professional baseball players, with 86% of all rotator cuff surgical procedures reported as débridement. RTS rates following débridement and repair are disappointing, at 50.8% and 33.3%, respectively. For players who do return, performance declines after surgery., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: A recently introduced classification of medial ulnar collateral ligament (UCL) tears has demonstrated high interobserver and intraobserver reliability, but little is known about its prognostic utility. The purpose of this study was to assess the relationship of the magnetic resonance imaging (MRI)-based classification system and nonoperative vs. operative management. Secondary objectives included subanalysis of baseball players., Methods: Eighty-five consecutive patients with UCL tears after a standardized treatment paradigm were categorized as operative vs. nonoperative. UCL tears of patients with a minimum of 1-year follow-up were retrospectively classified using the MRI-based classification system. Subanalyses for baseball players included return-to-play and return-to-prior performance., Results: A total of 80 patients (62 baseball players, 54 pitchers) met inclusion criteria. A total of 51 patients underwent surgery, and 29 patients completed nonoperative management. In baseball players, 59% of the proximal tears were treated nonoperatively and 97% of the distal tears were treated operatively; 100% of the proximal partial-thickness tears and 100% of the distal complete tears were treated nonoperatively and operatively, respectively. Patients with distal (odds ratio: 48.4, P < .0001) and complete (odds ratio: 5.0, P = .004) tears were more likely to undergo surgery. Baseball players, regardless of position, were determinants of operative management, and there was no difference in return-to-play clearance and return-to-prior performance between the operative and nonoperative groups., Conclusion: A reliable 6-stage MRI-based classification addressing UCL tear grade and location may confer decision making between operative and nonoperative management. Complete and distal tears carry a markedly increased risk of failing nonoperative care compared with proximal, partial tears., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Several guidelines for the prevention of throwing injuries recommend a sufficiently long off-season; however, few studies providing scientific evidence to support these recommendations exist. Our study aimed to clarify the association between off-season duration and throwing elbow injuries among elementary school-aged baseball players., Methods: This study enrolled 680 elementary school-aged baseball players who underwent medical checkups. The experience with elbow pain and the off-season duration were investigated via the administration of a self-completed questionnaire. Ultrasonographic assessment of the elbow joint was performed on the day of the medical checkup to assess for morphologic abnormalities., Results: The prevalence of elbow pain and morphologic abnormalities of the medial epicondyle (medial epicondyle lesions) was significantly decreased when the subjects' off-season duration was longer. Multivariate analysis revealed that the risk of elbow pain was significantly lower in the group whose off-season lasted 1 to 2 months (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.15-0.62; P = .0006) and in the group whose off-season lasted longer than 2 months (OR, 0.59; 95% CI, 0.37-0.95; P = .0316). The risk of medial epicondyle lesions was also significantly lower in the group whose off-season lasted 1 to 2 months (OR, 0.39; 95% CI, 0.22-0.67; P = .0005) and in the group whose off-season lasted longer than 2 months (OR, 0.36; 95% CI, 0.23-0.56; P < .0001). On the contrary, no significant correlation was found between capitellar osteochondritis dissecans and off-season duration., Conclusion: Off-season duration has a significant correlation with elbow pain and morphologic abnormalities of the medial elbow joint in elementary school-aged baseball players., (Copyright © 2019 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: It is unclear how a glenohumeral internal rotation (IR) loss (GIRLoss), a glenohumeral external rotation (ER) gain (GERGain), or a total rotational motion (TRM) deficit (TRMD) predict medial ulnar collateral ligament (MUCL) injury risk among high school (HS), college (COLL), and professional (PRO) baseball pitchers with and without MUCL injury. We hypothesized that pitchers with MUCL injury would have more GIRLoss and TRMD compared with pitchers without MUCL injury, with no differences in IR, ER, TRM, GIRLoss, GERGain, and TRMD., Methods: The study equally divided 216 male HS, COLL, and PRO pitchers into the MUCL injury group (n = 108) and a control group (n = 108) without MUCL injury. The control group was matched with the MUCL injury group according to number, level of play, and age. Bilateral shoulder passive IR/ER was measured and GIRLoss, GERGain, TRM, and TRMD calculated. A 2-way analysis of variance (P < .05) was used to assess shoulder rotational differences among the 2 groups and 3 pitching levels., Results: Compared with the control group, the MUCL injured group had more GIRLoss (21° ± 14° vs. 13° ± 8°; P < .001), GERGain (14° ± 9° vs. 10° ± 9°; P = .004), and TRMD (7° ± 13° vs. 3° ± 9°; P = .008). For all pitching levels, approximately 60% of pitchers in MUCL injury group had GIRLoss >18° compared with approximately 30% of those in the control group. Approximately 60% of pitchers in the MUCL injury group had TRMD >5° compared with 50% of pitchers in the control group. No differences were observed among HS, COLL, and PRO pitchers for GIRLoss (16° ± 12°, 17° ± 11°, 19° ± 13°, respectively; P = .131), GERGain (11° ± 9°, 11° ± 10°, 13° ± 10°, respectively; P = .171), TRMD (5° ± 11°, 6° ± 11°, 5° ± 14°, respectively; P = .711), and throwing shoulder ER (111° ± 10°, 111° ± 11°, 113° ± 9°, respectively; P = .427), IR (50° ± 11°, 49° ± 11°, 48° ± 10°, respectively; P = .121), and TRM (162° ± 14°, 160° ± 15°, 161° ± 14°, respectively; P = .770)., Conclusions: Greater GIRLoss, GERGain, and TRMD in MUCL injured pitchers compared with uninjured pitchers implies these variables may be related to increased MUCL injury risk, especially because GIRLoss >18° and TRMD >5° demonstrate an increased MUCL injury risk. Shoulder rotational motion and deficits do not vary among HS, COLL, and PRO levels of pitchers., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: How shoulder injuries treated before the Major League Baseball (MLB) draft affect the player's performance over their career is unclear. The purpose of this study was to determine whether prior shoulder injuries were associated with a difference in the level of performance and advancement of MLB draftees., Methods: Before entering the draft, 119 professional baseball players from 2004 to 2010 were treated for a shoulder injury (73% treated surgically) as an amateur. A 3:1 matched case-control was performed to players without prior shoulder injuries by age, position, round selected, and signing bonus. Follow-up data were collected in 2016, and professional advancement, disabled list time, and in-game performance statistics for pitchers were analyzed and compared., Results: Players with a prior shoulder injury had a statistically higher chance to be assigned to the disabled list then controls (P = .03), but there was no difference in disabled list time or professional advancement. Pitchers with a prior shoulder injury pitched a statistically lower number of innings per game than controls (P = .04). All other in-game performance statistics were not statistically different. The type of treatment did not have any effect on future performance or advancement., Conclusions: Professional baseball players treated for prior shoulder injuries at the amateur level were more likely to sustain future disability than their matched controls, but it did not affect professional advancement., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Risk factors for ulnar collateral ligament injury (UCLI) are unclear despite increasing injury rates. We sought to summarize UCLI risk factors in baseball players., Methods: A computer-assisted search of 4 databases was performed using keywords related to UCLI risk factors. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were used for study methodology. Odds ratios and 95% confidence intervals were calculated for dichotomous outcomes, and mean differences and 95% confidence intervals were calculated for continuous outcomes using a random-effects model., Results: Thirteen studies qualified for inclusion. A greater nondominant (ND) shoulder internal rotation (IR) range of motion (ROM) at 90° abduction arm demonstrated strong evidence as a significant risk factor for UCLI (P < .001) compared with a control group. Mean overall velocity (P < .001), fastball velocity (P < .001), changeup velocity (P = .03), and curveball velocity (P = .01), as well as fewer years of player experience (P < .001), less humeral retrotorsion in the ND arm (P < .001), and greater absolute side-to-side differences in retrotorsion (P = .006) were all moderate-evidence risk factors compared with control groups. Strong evidence suggests total ROM arc at 90° abduction in the dominant arm was not a risk factor for UCLI (P = .81)., Conclusions: Greater ND shoulder IR ROM and less humeral retrotorsion (in professional and amateur players) as well as pitching velocity (in professional players) demonstrated strong to moderate evidence as risk factors for UCLI. Dominant arm total arc of motion, external, or IR ROM were not risk factors for UCLI. Standardized collection and reporting of risk factors is recommended to more clearly elucidate definitive risk factors for UCLI., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: This study evaluated the clinical outcome of arthroscopic treatment for anterior shoulder dislocation in elite and professional baseball players., Methods: This study included 51 baseball players who underwent arthroscopic Bankart repair between 2008 and 2015. The follow-up duration was set at 24 months or longer, based on clinic visit or telephone survey. After surgery, players who played in 1 or more official games were considered to have returned to play (RTP), and those who participated in more than 10 official games were considered to have solidly returned to play (sRTP). The RTP and sRTP rates were analyzed by player position (pitcher, catcher, and in-fielder), and the period of RTP after surgery (rehabilitation period) was investigated., Results: Of 51 baseball players (mean age, 20.9 years), 14 were pitchers, 6 were catchers, and 31 were in-fielders. Pitchers showed 64% RTP and 57% sRTP, catchers, 83% RTP and 83% sRTP, and in-fielders, 90% RTP and 90% sRTP. The overall RTP and sRTP rates were 82% and 80%, respectively. The average RTP period after surgery (rehabilitation period) was 8.4 months, with 9.6, 9.1, and 7.4 months for pitchers, catchers, and in-fielders, respectively., Conclusions: The RTP after arthroscopic Bankart repair shows favorable results, with the nonthrowing shoulder and in-field position yielding the best results. Players undergoing arthroscopic Bankart repair and the surgeon should be aware of the possible outcomes based on the throwing/nonthrowing arm and various positions., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Rounding of the posterior glenoid rim is observed in young throwing athletes with internal shoulder impingement and is considered developmental dysplasia of the glenoid. The aim of our study was to determine the incidence rate of dysplastic changes of the glenoid within a group of 92 young baseball players., Methods: The study group included 92 male baseball players, with a mean age of 14.63 years. Of these patients, 30 were diagnosed with Little Leaguer's shoulder and 62 with a painful baseball-throwing shoulder with no abnormal findings on x-ray. The posterior glenoid rim of the affected shoulder was compared with the contralateral nonpainful shoulder, with the 2 following outcomes measured on radiographs obtained using the modified Bernageau imaging method: the distance between the anterior and posterior glenoid rims and the presence or absence of dysplasia of the posterior glenoid rim., Results: The mean distance between the anterior and posterior glenoid rims was significantly shorter in the painful shoulders (mean, 26 mm) than in the nonpainful shoulders (mean, 29 mm; P < .0001). Dysplasia of the posterior glenoid rim was identified in 89 painful shoulders (96.7%), with 9 cases (9.7%) identified on the unaffected contralateral side (P < .001). The presence of dysplasia was not correlated with the age at which baseball playing began., Conclusion: The incidence of dysplasia of the posterior glenoid rim is high (96.7%) among young baseball players with a painful shoulder. The identified dysplasia may be related to impaired development of the inferior peripheral secondary glenoid ossification center due to repetitive throwing., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Capitellar osteochondritis dissecans (COCD) is a common elbow injury in young baseball athletes. It may be asymptomatic at the early stage and may progress if left untreated. This study investigated the effectiveness of ultrasonography (US) screening for COCD in adolescent baseball players and identified risk factors of COCD., Methods: A cross-sectional analysis study was conducted among baseball athletes aged 12 to 18 years. US screening of the throwing elbow was performed in all participants, and additional magnetic resonance imaging (MRI) was arranged for those with abnormal screening results. The prevalence of COCD was calculated according to MRI results. The US findings were compared with MRI findings. Data for characteristics, joint range of motion, and quality of pain were collected and analyzed using a logistic regression model to identify the risk factors of COCD., Results: A total of 299 adolescent baseball players were screened, and 17 were found to have COCD according to US findings. MRI was performed in 15 of these 17 players, and the MRI findings further confirmed COCD in 10 players (66.7%). The presence of elbow pain while at rest, body height, and age at introduction to baseball were predictors of COCD., Conclusions: Although the effectiveness of diagnosing stage 1 COCD is satisfactory, US is a helpful tool for detecting stage 2 and higher-stage COCD. Elbow resting pain, lower body height, and introduction to baseball at a younger age are risk factors for COCD., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The Kerlan-Jobe Orthopaedic Clinic (KJOC) score has been used to describe various parameters of throwing shoulder and elbow function for the return to play after a long period of rehabilitation, such as after ulnar collateral ligament reconstruction. No study has yet to identify how scapular dyskinesis (SD) in baseball players affects the KJOC score. This study investigated the relationship of the KJOC score to SD evaluated in collegiate baseball players with and without upper extremity injury., Materials and Methods: The study participants were 30 male collegiate baseball players (13 pitchers) belonging to the National Collegiate Athletic Association D-I conference. Participants were assessed with the KJOC instrument in the beginning (PRE) and end (POST) of the season. The SD test was conducted (PRE) in shoulder flexion to identify SD RESULTS: The mean value of KJOC score was significantly less in POST than that of PRE for the pitchers with SD (89.3 and 60.5, respectively; P = .001), whereas no difference was found in the KJOC score between PRE and POST for the pitchers without SD. For the position players, no difference in the mean value of KJOC score was found between PRE and POST, regardless of SD., Conclusion: The results of this study provide evidence that collegiate baseball pitchers with mild SD may have lower KJOC scores, particularly setup or relief pitchers., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Although the pronator teres muscle, a major dynamic stabilizer of elbow valgus stress during throwing, frequently presents stiffness, its relationship with elbow injuries in youth baseball players is unknown. This study investigated the relationship between the elasticity of the pronator teres muscle and elbow injuries in youth baseball players., Methods: The strain ratio (SR) of 15 individuals with osteochondritis dissecans of the humeral capitellum (OCD group), 67 individuals with medial epicondylar fragmentation (medial injury group), and 115 healthy individuals (control group) was measured as the index of the elasticity of the pronator teres muscle using ultrasound strain elastography. In addition, the forearm and glenohumeral joint rotation range of motion was measured., Results: The SR of the throwing arm was significantly higher in the OCD and medial injury groups than in the control group (both P <.001). In the OCD group, the SR was significantly higher in the throwing arm than in the nonthrowing arm (P <.001), whereas in the medial injury group, there was no significant difference between both arms. The glenohumeral joint external rotation range of motion of the throwing arm was moderately negatively correlated with the SR (r = -0.478, P <.001)., Conclusions: Stiffness of the pronator teres muscle was exhibited only in the throwing arm of individuals with OCD and in both arms in individuals with medial elbow injury. These findings may contribute to an accurate evaluation and prevention of elbow injuries in youth baseball players., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: There has been increasing interest regarding the association between pitch counts, as well as total workload per season, and the risk of injury among Major League Baseball (MLB) starting pitchers., Methods: We used publicly available databases to identify all MLB starting pitchers eligible for play who made at least 5 starts in seasons between 2010 and 2015. For all included pitchers, annual pitching statistics (number of starts, total season pitch counts, total season inning counts, and average pitch count per game started) and annual disabled list (DL) information (time on DL for any reason and time on DL related to upper extremity, lower extremity, or axial body injury) were collected. A multiple logistic regression analyzed games started, pitch counts, innings pitched, and pitches per start during all previous seasons as a risk factor for injury in the current season, controlling for previous injury., Results: A total of 161 starting MLB pitchers met the inclusion criteria. With the exception of total innings pitched from 2010-2011 being significantly associated with DL placement in 2012 (no DL, 310.5 ± 97.5 innings; DL, 344.7 ± 85.9 innings; P = .040), no other finding for starts, pitch counts, innings, or pitches per start in the cumulative years from 2010-2014 had a significant association with pitcher placement on the DL for any musculoskeletal reason or for an upper extremity reason between 2011 and 2015., Conclusions: In this study, we demonstrate that there is no association between preceding years of cumulative pitches, starts, innings pitched, or average pitches per start and being placed on the DL for any musculoskeletal reason., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: There has been no study on radiologic changes after medial ulnar collateral ligament (MUCL) reconstruction and related clinical features., Methods: Data from 39 baseball players who underwent MUCL reconstruction were collected and analyzed. The baseball players were classified into 2 groups according to the starting point of the humeral tunnel: (1) the lower tip of the medial epicondyle (group NA, n = 21) and (2) the remnant of the MUCL (group A, n = 18). Bone tunnel characteristics and changes were evaluated by computed tomography (CT) at 3 and 9 months postoperatively. Outcome measures consisted of the visual analog scale, range of motion (ROM), the Conway scale, and the presence of ulnar nerve irritation postoperatively., Results: The mean diameter of the humeral entry was 4.0 mm (range, 3.4-5.1 mm) on the first CT scan, which increased to 5.5 mm (range, 3.2-7.2 mm) on the follow-up CT scan (P < .001). The mean diameter of the ulnar tunnel was 2.8 mm (range, 1.1-3.3 mm) on the first CT scan, which decreased to 1.6 mm (range, 0-4.3 mm) on the follow-up CT scan (P < .001). The between-group comparison revealed no differences in the changes in the diameter of the humeral and ulnar tunnels. A statistically significant correlation was not found between athletic performance measured by the Conway scale and the radiologic changes on CT evaluation (P = .182). Group A showed improvement in extension from 7° preoperatively to 1° postoperatively (P < .001) and in flexion from 126° preoperatively to 136° postoperatively (P < .001), while group NA did not achieve statistical significance in ROM improvement after the operation., Conclusions: Humeral tunnel widening was commonly observed, while the ulnar tunnel was maintained or became narrowed conversely. The humeral tunnel placements did not affect tunnel changes after the surgical procedure; however, MUCL reconstruction with the anatomic location of the humeral tunnel yielded substantial improvement in elbow ROM., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Although much as been done to characterize trends of medial ulnar collateral ligament (UCL) reconstruction in pitchers, outcomes in position players (PPs) (non-pitchers) remain undefined in the current literature., Methods: Three resources were combined to identify all known Major League Baseball and Minor League Baseball (MiLB) PPs who have ever undergone UCL reconstruction. A multitude of player and surgical variables were included. Trends over time were analyzed collectively, based on level of play, revision status (primary vs revision), and position. Additional comparisons were made with a known cohort of professional baseball pitchers having undergone UCL reconstruction., Results: We identified 168 UCL reconstructions in professional PPs. The annual rate of primary UCL reconstruction rose significantly from 1984 to 2015 (P < .001), and the proportion of cases performed in MiLB PPs (vs Major League Baseball PPs) increased steadily (P < .001). Of PPs, 75.5% returned to play at any level at a mean of 342 days. Catchers demonstrated the lowest return-to-play (RTP) rate (58.6%) compared with infielders (75.6%) and outfielders (88.9%). The overall revision rate was low, at 4.8%. Compared with pitchers, PPs demonstrated a lower rate of RTP (75.5% for PPs vs 83.7% for pitchers, P = .040) but shorter RTP times for those able to return (342 days for PPs vs 435 days for pitchers, P < .001)., Conclusions: The incidence of UCL reconstruction in PPs continues to rise, a trend that is significantly more pronounced at the MiLB level. Although PPs (particularly catchers) are less likely to return to professional baseball compared with pitchers, those who are able to RTP do so more rapidly., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: The primary purpose of this work is to provide an epidemiologic report on every known ulnar collateral ligament (UCL) reconstruction performed in professional baseball with a special focus on outcomes and survivorship., Methods: Three resources, including the Major League Baseball (MLB) injury tracking system, were combined and cross-referenced to identify all known professional baseball pitchers who had ever undergone UCL reconstruction from 1974 to 2016. Variables analyzed included injury date, surgery date, return to play rates, time out of play, and revision status. Trends over time were analyzed collectively and by level of play at the time of surgery. A minimum of 2 years of follow-up was required for return to play analysis., Results: We identified 1429 UCL reconstructions. The annual rate of primary and revision UCL reconstructions rose significantly (P < .001). Most players (83.7%) returned to any level of play at a mean of 435 days, whereas 72.8% (P < .001) returned to their prior level at a mean of 506 days. Major League Baseball players were more likely than Minor League Baseball players to return to any level (94.6% vs. 79.0%, P < .001) and their prior level of performance (80.0% vs. 69.1%, P = .04). The mean overall survivorship free from revision and still playing was 3.8 years (3.9 for primary vs. 2.9 for revisions, P = .018). The revision rate was 6.7% and was higher for Major League Baseball (9.4%) vs. Minor League Baseball (5.2%, P = .004)., Conclusions: This study represents the most robust epidemiologic report of UCL reconstruction in baseball to date, and a multitude of novel findings are reported., (Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: To prevent elbow injury in baseball players, various methods have been used to measure medial elbow joint stability with valgus stress. However, no studies have investigated higher levels of elbow valgus stress. This study investigated medial elbow joint space gapping measured ultrasonically resulting from a 30 N valgus stress vs. gravitational valgus stress after a repetitive throwing task., Methods: The study included 25 high school baseball players. Each subject pitched 100 times. The ulnohumeral joint space was measured ultrasonographically, before pitching and after each successive block of 20 pitches, with gravity stress or 30 N valgus stress. Two-way repeated measures analysis of variance and Pearson correlation coefficient analysis were used., Results: The 30 N valgus stress produced significantly greater ulnohumeral joint space gapping than gravity stress before pitching and at each successive 20-pitch block (P < .01). For the 2 stress methods, ulnohumeral joint space gapping increased significantly from baseline after 60 pitches (P < .01). Strong significant correlations were found between the 2 methods for measurement of medial elbow joint space gapping (r = 0.727-0.859, P < .01)., Conclusions: Gravity stress and 30 N valgus stress may produce different effects with respect to medial elbow joint space gapping before pitching; however, 30 N valgus stress appears to induce greater mechanical stress, which may be preferable when assessing joint instability but also has the potential to be more aggressive. The present results may indicate that constraining factors to medial elbow joint valgus stress matched typical viscoelastic properties of cyclic creep., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)