Preseason Assessment of Radiographic Abnormalities in Elbows of Little League Baseball Players

Adaptive pathology: new insights into the physical examination and imaging of the thrower's shoulder and elbow

Throwing with high velocity requires extremes of glenohumeral external rotation of the abducted arm where particularly high forces in the shoulder and elbow are endured. Repeated throwing leads to dominant-arm bony remodeling of the humerus, glenoid, and elbow, and multiple soft tissue changes that would be considered abnormal. Many of these features are thought to be adaptive and protective. The purpose of this work is to (1) define the concept of adaptive pathology; (2) review the mechanics of the throwing motion; (3) review pertinent physical examination and imaging findings seen in asymptomatic throwers' shoulders and elbows and describe how these changes develop and may be adaptive-allowing the thrower to perform at high levels; and then (4) review the principles of surgical treatment in the throwing athletes, which should focus on reducing symptoms, but not necessarily restoring the thrower's anatomy to normal.

Pediatric thrower's elbow: maturation-dependent MRI findings in symptomatic baseball players

BACKGROUND

Elbow pain is common among youth baseball players and elbow MRI is increasingly utilized to complement the clinical assessment.

OBJECTIVE

To characterize, according to skeletal maturity, findings on elbow MRI from symptomatic youth baseball players.

MATERIALS AND METHODS

This IRB-approved, HIPAA-compliant retrospective study included pediatric (<18 years of age) baseball players with elbow pain who underwent MRI examinations between 2010 and 2021. Two radiologists, blinded to the outcome, independently reviewed examinations to categorize skeletal maturity and to identify osseous and soft tissue findings with consensus used to resolve discrepancies. Findings were compared between skeletally immature and mature patients and logistic regression models identified predictors of surgery.

RESULTS

This study included 130 children (115 boys, 15 girls): 85 skeletally immature and 45 mature (12.8±2.3 and 16.2±1.0 years, respectively, p<0.01). Kappa coefficient for interobserver agreement on MRI findings ranged from 0.64 to 0.96. Skeletally immature children, when compared to mature children, were more likely to have elbow effusion (27%, 23/85 vs 9%, 4/45; p=0.03), medial epicondyle marrow edema (53%, 45/85 vs 16%, 7/45; p<0.01), avulsion fracture (19%, 16/85 vs 2%, 1/45; p=0.02), and juvenile osteochondritis dissecans (OCD, 22%, 19/85 vs 7%, 3/45; p=0.04), whereas skeletally mature children were more likely to have sublime tubercle marrow edema (49%, 22/45 vs 11%, 9/85; p<0.01) and triceps tendinosis (40%, 18/45 vs 20%, 17/85; p=0.03). Intra-articular body (OR=4.2, 95% CI 1.5-47.8, p=0.02) and osteochondritis dissecans (OR=3.7, 95% CI 1.1-11.9, p=0.03) were independent predictors for surgery.

CONCLUSION

Differential patterns of elbow MRI findings were observed among symptomatic pediatric baseball players based on regional skeletal maturity. Intra-articular body and osteochondritis dissecans were independent predictors of surgery.

Increased Medial Elbow Torque Is Associated With Ball Velocity Rather Than a History of Medial Elbow Injuries in Youth Baseball Pitchers

PURPOSE

This study compared medial elbow torque in youth baseball pitchers with and without a history of medial elbow injuries to determine the relationship between medial elbow torque during pitching and having a history of medial elbow injuries.

METHODS

We recruited 171 youth baseball pitchers aged 9 to 12 years old. The exclusion criteria included current pain with pitching, history of surgery on the tested extremity, or osteochondritis dissecans of the humeral capitellum. The participants were grouped into 3 groups: injury <1-year, injury >1-year, and control, based on ultrasonographic abnormalities of the elbow and the presence of elbow pain. Pitchers pitched 3 fastballs while wearing a sensor sleeve that recorded the medial elbow torque, arm speed, and shoulder rotation. Ball velocity was measured using a radar gun.

RESULTS

The final analysis included 164 pitchers. Thirty were assigned to the injury <1-year group, 34 to the injury >1-year group, and 100 to the control group. The medial elbow torque was significantly greater in the injury <1-year group compared with the control group (18.6 ± 3.6 Nm vs 16.2 ± 4.8 Nm, P = .023). A multiple regression analysis revealed that ball velocity (B = 0.282, P < .001) and body weight (B = -0.224, P < .001) were significantly associated with medial elbow torque, but not with the history of medial elbow injuries.

CONCLUSIONS

Increased medial elbow torque was associated with greater ball velocity regardless of the history of medial elbow injuries. Youth baseball pitchers with a history of medial elbow injuries within one year had greater medial elbow torque during pitching; however, having a history of medial elbow injuries was not an independent factor in increasing medial elbow torque. Limiting the ball velocity can reduce medial elbow torque and may prevent elbow injuries in youth baseball pitchers.

LEVEL OF EVIDENCE

Level II, prospective comparative prognostic investigation with the patients enrolled at different time point.

Stand-up test could be a helpful adjunct for screening elbow disorders in Little League baseball players

BACKGROUND

The purpose of this study is to justify the result of the modified Stand-Up test (MSUT) in Little League baseball players and to clarify the association with sports related disorders in the elbow.

METHODS

A total of 245 (240 boys and 5 girls) Little League baseball players aged 9 to 12 underwent physical examination, elbow ultrasonography and questionnaires during a routine medical checkup. In addition, the MSUT, based on the Japanese Orthopaedic Association (JOA)'s original Stand-Up test to evaluate the risk of Locomotive syndrome, was performed.

RESULTS

Seventeen osteochondritis dissecans (OCD) of capitellum and 4 medial epicondylar fragmentation (MEF) cases were diagnosed with ultrasonography in 242 players. Based on the MSUT, five boys could not stand up from 40 cm platform with the single leg stance, two of whom complained of current elbow pain, three of whom diagnosed with a positive finding with ultrasonography. Odds ratio (95% confidence limits) of risk factors for failing to the 40 cm-MSUT with the single leg stance were: incidence of current elbow pain 5.7 (0.9-35.5); OCD (Grade 1b and 2) 8.2 (0.8-83); and MEF 19.5 (1.7-230).

CONCLUSION

Two percent of Little League baseball players were unable to stand up from a 40 cm high platform/stool with the single leg stance by the MSUT and it was associated with an increase in MEF or OCD diagnosis by ultrasonography and presence of elbow pain. These results suggest that players who failed to the 40 cm-MSUT with the single leg stance are at risk of elbow disorders. Also, these results are consistent with previous research on throwing injuries that have associated poor control in the legs or trunk with pain and injury involving the upper extremities. MSUT, a relatively simple procedure, may be a helpful adjunct for screening to estimate readiness for resuming general physical activity in Little League baseball players.

High-definition magnetic resonance images on medial elbow injuries in preadolescent Little Leaguers

BACKGROUND

The incidence of throwing-related elbow injuries is still rising. The study aimed to enhance the pathology of acute medial elbow injuries among young Little Leaguers by examining the medial elbows of symptomatic 9-10 years old Little Leaguers using High-Definition Magnetic Resonance Images (HDMRI), which uses a small-diameter surface coil on the target area, leading to greater image resolution.

METHOD

We identified Little Leaguers aged 9-10 years old. To minimize the detection of the chronic adaptative changes, players who experienced the medial elbow pain previously and whose HDMRI had not been taken within 4 weeks from the onset of medial elbow pain were excluded. This study considered 21 players, and the mean age was 9.4 ± 0.5 years.

RESULT

The fragmentation of the medial epicondyle apophysis via HDMRI was found in 15 elbows (71.4%), while the avulsion was seen in three cases. The signal hyperintensity at the medial epicondyle apophysis was observed in 2 cases. Our data showed abnormal changes to the medial epicondyle apophysis and surrounding structures, such as the ulnar collateral ligament (UCL), flexor-pronator tendons or the coronoid process of the ulna. We detected 11 abnormalities on X-ray imaging, while 20 subjects showed some abnormal findings via HDMRI.

DISCUSSION

The current study showed that initial medial elbow injury in Little Leaguers without a history of previous elbow injury could be attributed to multi-structure injury. Over 90% of subjects were injured in the perichondrium, while 71.4% demonstrated a fragmentation of the secondary ossification center, and 14.3% experienced an avulsion of the medial epicondyle apophysis. Because the injuries were not limited to bony structures, HDMRI may be beneficial for the appropriate evaluation of medial elbow pain. The pathology of initial medial elbow injuries in young baseball players may be due to acute trauma instead of repetitive microtrauma.

High elasticity of the flexor carpi ulnaris and pronator teres muscles is associated with medial elbow injuries in youth baseball players

OBJECTIVES

The purpose of the present study was to measure the elasticities of the forearm flexor-pronator muscles in youth baseball players and examine their relationships with medial elbow injuries.

METHODS

We examined the strain ratios (SR) of the flexor digitorum superficialis (FDS), flexor carpi ulnaris (FCU), and pronator teres (PT) in 89 youth baseball players with medial epicondylar fragmentation (injury group) and in 142 healthy baseball players (control group). An index of muscle elasticity was determined using ultrasound strain elastography. The SR of each muscles was compared between the injury and control groups, and the SR of the both side arms was compared within group. Moreover, multivariable logistic regression analyses were conducted to examine the association of forearm muscle elasticity with medial elbow injuries.

RESULTS

The SR of the FCU and PT of the throwing arm were significantly higher in the injury group than in the control group (both P < .001). In the injury group, the SR of the FCU was higher in the throwing arm than in the non-throwing arm (P < .001), but no difference was noted for the PT. Multivariable logistic regression analyses showed that a 0.1 increase of the SR of the FCU of the throwing arm (odds ratio [OR] 1.30, 95% confidence interval [CI] 1.14-1.48) and PT of the throwing arm (OR 1.41, 95% CI 1.19-1.67) and the non-throwing arm (OR 1.31, 95% CI 1.12-1.54) was significantly associated with an increased prevalence of medial elbow injuries.

CONCLUSION

High elasticities of the FCU of the throwing arm and PT of both the arms were observed in individuals with medial elbow injuries, and were associated with increased prevalence of medial elbow injuries. These findings may be characteristic of medial elbow injuries in youth baseball players.

Squatting Throwing Is Not Associated With Increased Medial Elbow Torque in Youth Baseball Catchers

PURPOSE

To compare medial elbow stress during squatting throwing, standing throwing, and maximum effort throwing and to analyze its relationships with throwing variables and the hip joint internal rotation (IR) range of motion (ROM) in youth baseball catchers.

METHODS

Forty-five youth baseball catchers were recruited. Exclusion criteria included pain during throwing, history of surgery, or upper-extremity injuries within 12 months. Catchers performed 5 throws for each of the following throwing conditions: squatting throwing, standing throwing, and maximum effort throwing. Catchers were outfitted with a wearable sensor sleeve that recorded the medial elbow torque, arm speed, and shoulder rotation. Ball velocity was measured using a radar gun.

RESULTS

Final analysis included 42 catchers (mean age, 11.5 ± 1.2 years; mean catcher experience, 16.7 ± 10.3 months). The medial elbow torque was significantly greater during maximum effort throwing (19.0 ± 5.2 Nm) than during squatting throwing (14.3 ± 5.4 Nm) and standing throwing (15.7 ± 4.7 Nm) (both P < .001); there was no significant difference between squatting throwing and standing throwing. Multiple linear regression analysis showed that the ball velocity was significantly positively associated with the medial elbow torque during squatting throwing and standing throwing (P = .023 and P = .029, respectively). During squatting throwing, the hip IR ROM on the throwing side was significantly negatively associated with the medial elbow torque (P = .011).

CONCLUSIONS

The medial elbow torque during squatting throwing was equivalent to that during standing throwing. Increased medial elbow torque was associated with greater ball velocity during squatting throwing and standing throwing and with decreasing hip joint IR ROM on the throwing side during squatting throwing. Evaluation and stretching of the hip joint IR ROM on the throwing side may be important to decrease elbow stress during squatting throwing in youth baseball catchers.

LEVEL OF EVIDENCE

Level II, prospective comparative observational trial.

Risk factor for elbow symptom manifestation in young baseball players with asymptomatic medial elbow abnormalities: a prospective cohort study

Asymptomatic elbow abnormalities are relatively common in young baseball players, but the factors responsible are unclear. To prospectively identify risk factors related to symptom manifestation in asymptomatic elbow abnormalities, we recruited 573 baseball players (age: 7-14 years) at a pre-participation medical/physical examination in the preseason who were right-handed and had asymptomatic medial elbow abnormalities on ultrasound (US). Baseline preseason and postseason participant characteristics were assessed. A "symptomatic" elbow was defined as an elbow with medial elbow joint problems that prevented ball throwing for ≥ 8 days. After exclusions, 82 players were enrolled, of whom 22 (26.8%) developed a symptomatic elbow. In univariate analyses, the external and internal rotation strengths of the dominant shoulder were significantly greater in the symptomatic group than in the asymptomatic group (P = 0.021). Multivariate logistic regression analysis showed that the internal rotation strength of the dominant shoulder was a significant independent risk factor (odds ratio = 1.091, P = 0.027) for developing a symptomatic elbow. In young asymptomatic baseball players with abnormalities in the medial elbow region of the dominant arm on US, stronger preseason internal rotation strength of the dominant shoulder was a significant independent risk factor for the development of a "symptomatic" elbow.

The association of sport participation behaviors with throwing-arm health in Little League Baseball pitchers

Background and Hypothesis

There is increasing concern about the role sport specialization might play in the increasing injury rates observed among youth baseball pitchers. However, existing research on specialization in baseball has focused on high school and professional baseball populations. We hypothesized that pitchers who were highly specialized, reported pitching more than eight months in the past year, received private coaching, or pitched with pain or fatigue in the previous year would report worse throwing-arm health.

Methods

One-hundred eighty-four Little League pitchers (boys N = 181, age 9.8 ± 1.6 years old) between 7 and 12 years of age completed an anonymous, online questionnaire with their parents' assistance. The questionnaire consisted of participant demographics, sport specialization status, months of pitching per year, whether they traveled regularly to participate in showcases, if they received private coaching, whether they pitched with elbow or shoulder pain, whether they pitched with fatigue, and the Youth Throwing Score (YTS), a valid and reliable patient-reported outcome measure for youth baseball players. The associations between variables of interest and YTS were examined using multivariable linear regression, adjusting for covariates.

Results

Sport specialization, pitching year-round, and receiving private coaching were not associated with the YTS (P > .05). Pitching with pain in the previous year was associated with a worse YTS score than pitching without pain (least square mean [standard error]: 49.6 [1.8] vs. 57.8 [1.1], P < .001). Similarly, pitching with fatigue in the previous year was associated with worse YTS scores (least square mean [standard error]: 52.1 [1.4] vs. 55.3 [1.3], P = .01). Pitchers who reported traveling regularly for showcases scored worse on the YTS compared with those who did not travel regularly for showcase events (least square mean [standard error]: 51.0 [2.0] vs. 56.4 [0.9], P = .01).

Conclusions

Pitching with pain or fatigue was associated with worse throwing-arm health in Little League baseball pitchers. While traveling at least once a month to participate in showcases was also associated with worse throwing-arm health, specialization and private coaching were not related to worse throwing health. Clinicians working with pediatric patient populations should be aware that while the factors examined in this article were reported relatively infrequently, screening for Little League pitchers who participate in showcases or pitch with pain or fatigue may be an effective strategy for identifying these individuals who are at higher risk of injury.

Asymptomatic Medial Elbow Ultrasound Abnormality in Youth Baseball Players Is an Independent Risk Factor for Elbow Injury: A Prospective Cohort Study

Background

Youth baseball players who experience elbow pain during the season frequently exhibit radiographic elbow abnormalities. However, it is unknown whether asymptomatic elbow abnormalities are risk factors for in-season elbow injuries.

Purpose

To determine whether the preseason presence of asymptomatic medial epicondyle apophysitis is a risk factor for in-season elbow injuries in youth baseball players.

Study Design

Cohort study; Level of evidence, 2.

Methods

Youth baseball players (N = 210; age range, 7-12 years) with no pain or history of injury in their throwing arms underwent preseason evaluations that included shoulder and elbow range of motion measurements, shoulder muscle strength testing, and ultrasound elbow scans with a multifrequency 13-MHz linear array transducer. Over 1 year of play, the players and their parents maintained daily elbow pain diaries. Elbow injuries were defined as medial elbow symptoms that prevented ball throwing for ≥8 days.

Results

The preseason ultrasound evaluation revealed medial epicondyle apophysitis in 59 players. In the year following, elbow injuries occurred in 17 (28.8%) players with preseason medial epicondyle apophysitis and 18 (11.9%) players without apophysitis. Independent predictors of elbow injuries were preseason medial epicondyle apophysitis (odds ratio [OR], 2.488; 95% confidence interval [CI], 1.152-5.376; P = .02) and deficits of abduction (ABD) and external rotation of the dominant shoulder (OR, 0.963; 95% CI, 0.936-0.992; P = .012).

Conclusion

Asymptomatic medial epicondyle apophysitis and ABD and external rotation deficits in the dominant shoulder were risk factors for elbow injuries in 7- to 12-year-old youth baseball players. These findings may aid in the design of programs to prevent elbow injuries in this population.

Ulnar Collateral Ligament Reconstruction With the Modified Jobe Technique in Baseball Pitchers

Background:

Tearing and insufficiency of the ulnar collateral ligament (UCL) of the elbow result in valgus instability, which can lead to pain while throwing and decline in performance in overhead athletes.

Purpose:

To assess the clinical results of a modified UCL reconstruction technique using 1 bone hole in the ulna and 1 bone tunnel in the humerus in baseball players.

Study Design:

Case series; Level of evidence, 4.

Methods:

The inclusion criteria were medial elbow pain preventing effective playing, clinically medial elbow laxity, and magnetic resonance imaging results consistent with UCL injury. Patients who were engaged in other sports and in other positions in baseball except pitchers were excluded from this study. Our modified Tommy John procedure was performed via a muscle-splitting approach and an original single-bone-tunnel technique, using a suture anchor. After a minimum of 24 months, patients were evaluated using the Conway scale and the Timmerman-Andrews score.

Results:

Of 31 patients, 20 baseball pitchers (20 male: 5 high school, 5 collegiate, 8 nonprofessional, and 2 professional pitchers) were reviewed. The mean patient age at the time of operation was 21.9 years, and the mean postoperative follow-up period was 35.1 months (range, 24-66 months). The mean Timmerman-Andrews subjective score improved significantly from pre- to postoperatively (from 68.3 to 98.3; P < .05); the objective score also improved significantly (from 81.1 to 96.4; P = .01). No complications were detected at the latest follow-up. Overall, 19 patients were able to return to their preinjury level of sports or higher.

Conclusion:

UCL reconstruction with 1 bone hole in the ulna and 1 bone tunnel in the humerus demonstrated satisfactory results in baseball pitchers. Our modified technique was safe and achieved satisfactory clinical results, with a 95% rate of return to sports.

Prevalence and Consequences of Sport Specialization Among Little League Baseball Players

BACKGROUND

Baseball is one of the most popular boy's youth sports, and there has been a rise in the rates of certain overuse injuries among players. Specialization has been identified as a risk factor for overuse injury in high school athlete populations, but there is little understanding of the prevalence or consequences of sport specialization in Little League baseball players.

HYPOTHESIS

Sport specialization will be highly prevalent among Little League baseball players and specialization will be associated with worse throwing arm health.

STUDY DESIGN

Cross-sectional study.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 246 Little League baseball players (male; N = 241; age, 9.5 ± 1.6 years) between 7 and 12 years old completed an anonymous, online questionnaire with their parent's assistance. The questionnaire consisted of participant demographics and baseball participation information, including sport specialization status and the Youth Throwing Score (YTS), a valid and reliable patient-reported outcome measure for youth baseball players.

RESULTS

Only 29 (11.8%) players met the criteria for high specialization. Approximately one-third of all players (n = 77; 31.3%) reported participating in baseball year-round or receiving private coaching outside of their league (n = 81; 32.9%). Highly specialized athletes demonstrated worse scores on the YTS on average compared with low-specialization athletes (mean [SE]: 56.9 [1.6] vs 61.1 [1.2]; P = 0.01). Similarly, pitching in the previous year (P < 0.01) or traveling overnight regularly for showcases (P = 0.01) were associated with a worse score on the YTS.

CONCLUSION

While the prevalence of high sport specialization was low among Little League baseball players, other behaviors associated with specialization such as year-round play and the receiving of private coaching were more common. Highly specialized Little League players demonstrated worse throwing arm health compared with low-specialization players.

CLINICAL RELEVANCE

Little League players and their parents may represent a potential target audience for dissemination campaigns regarding sport specialization.

High Thoracic Kyphosis and Backward Trunk Inclination Angles in the Single-Leg Standing Position Associate With Medial Elbow Injuries in Youth Baseball Players: A Cross-Sectional Study

CONTEXT

Baseball pitching is a coordinated movement involving the spine. A previous study indicated that increased thoracic kyphosis angle in a standing position was a risk factor for medial elbow injuries in youth baseball players. However, spinal alignments in single-leg standing and their relationships with medial elbow injuries, scapular alignment, or hip joint range of motion are unclear.

OBJECTIVE

To examine the difference in spinal alignment between standing and single-leg standing positions in youth baseball players and analyze their relationship with elbow injuries, scapular alignment, or hip joint range of motion.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

There were 51 youth baseball players with medial epicondylar fragmentation (medial elbow injury group) and 102 healthy youth baseball players (control group).

MAIN OUTCOME MEASURES

Thoracic kyphosis, lumbar lordosis, and trunk inclination angles during standing and single-leg standing, forward scapular posture, and hip joint range of motion.

RESULTS

In the single-leg standing position, the thoracic kyphosis and backward trunk inclination angles were significantly higher in the medial elbow injury group than in the control group (P = .016 and P = .046, respectively). In the standing position, no significant difference was observed between both groups. The thoracic kyphosis angle in single-leg standing was positively correlated with the bilateral forward scapular posture in the medial elbow injury (P = .008 and P < .001 on the throwing and nonthrowing sides, respectively) and control (P = .010 and P = .032 on the throwing and nonthrowing sides, respectively) groups.

CONCLUSIONS

High thoracic kyphosis and backward trunk inclination angles are characteristics during single-leg standing in youth baseball players with medial elbow injuries. Spinal alignment measurement in single-leg standing may be useful for identifying youth baseball players who are at risk for sustaining medial elbow injury.

Sport specialization is associated with upper-extremity overuse injury in high school baseball players

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.

Progressive Elbow Magnetic Resonance Imaging Abnormalities in Little League Baseball Players Are Common: A 3-Year Longitudinal Evaluation

BACKGROUND

Prior studies have revealed magnetic resonance imaging (MRI) evidence of elbow pathology in single-season evaluation of competitive youth baseball players. The natural history of these findings and risk factors for progression have not been reported.

PURPOSE

To characterize the natural history of bilateral elbow MRI findings in a 3-year longitudinal study and to correlate abnormalities with prior MRI findings, throwing history, playing status, and physical examination.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective study of Little League players aged 12 to 15 years was performed. All players had preseason and postseason bilateral elbow MRI performed 3 years before this study. Players underwent repeat bilateral elbow MRI, physical examination, and detailed assessment of throwing history, playing status, and arm pain. Imaging was read by a blinded musculoskeletal radiologist and compared with prior MR images to assess for progression or resolution of previously identified pathology.

RESULTS

All 26 players who participated in the previous single-season study returned for a 3-year assessment. At the completion of the study, 15 players (58%) had dominant arm MRI pathology. Eighty percent (12/15 players) of MRI findings were new or progressive lesions. Players with postseason MRI pathology at the beginning of the study were more likely to have MRI pathology at the 3-year follow-up than players with previously normal postseason MRI (P < .05), although 6 of the 14 players (43%) with previously normal MRI developed new pathology. Year-round play was a significant predictor of tenderness to elbow palpation (P = .027) and positive MRI findings at 3 years (P = .047). At the 3-year follow-up, 7 players (27%) reported having throwing elbow pain and 3 had required casting. Additionally, differences were noted in the dominant arm's internal and external rotation in those that continued to play baseball (P < .05).

CONCLUSION

Dominant elbow MRI abnormalities are common in competitive Little League Baseball players. Year-round play imparts significant risk for progression of MRI pathology and physical examination abnormalities.

Ultrasonography has high positive predictive value for medial epicondyle lesions among adolescent baseball players

PURPOSE

Only few studies have investigated medial epicondyle (MEC) lesions, particularly in the 12-18 age group. To the best of our knowledge, no study has compared ultrasonography (US), radiography and magnetic resonance imaging (MRI) in detecting MEC lesions. The aims of this study were to examine the value of US for detecting MEC lesions and to investigate correlations among diagnostic tools.

METHODS

A prospective, comparative study was performed. Young baseball players from southern Taiwan were recruited, and basic characteristics, as well as passive range of motion (pROM) of the upper extremities, were recorded. Screening US was performed to identify MEC lesions, and players with MEC lesions received follow-up plain radiography and MRI.

RESULTS

A total of 299 young baseball players were screened using US, and 28 of 299 players with possible MEC lesions were identified with a positive predictive value (PPV) of 88% according to MRI findings. The MEC lesions were primarily comprised of unfused ossicles and bony fragmentation. Other diagnoses, including UCL strain and medial epicondylitis, were also found by MRI in players with abnormal US screening results. The pROM of shoulder external rotation (ER) of the throwing hand was significantly reduced in players with MEC lesions (p = 0.006).

CONCLUSIONS

Bony cortical discontinuity or fragmentation over the MEC warrants further research, and US provides good PPV for types of MEC lesions. Decreased shoulder ER may relate to MEC lesions and should be taken into consideration. The use of US may facilitate early detection and intervention.

LEVEL OF EVIDENCE

IV, Cross-sectional study.

A Comparison of Team Sport Volume Surveyed Between High School and Club Sport Coaches

BACKGROUND

Club sport participation is increasingly common among high school athletes. Sport participation characteristics may vary widely between the high school and club sport settings. However, there have been no large-scale comparisons of sport participation volume between high school and club teams from similar sports.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the sport participation characteristics of high school and high school-aged club teams. We hypothesized that club team athletes would participate in more months per year and hours per week and would take more overnight trips than high school athletes and that club team coaches would be less likely to track their athletes' sport volume than high school coaches.

STUDY DESIGN

Cross-sectional study.

METHODS

A total of 769 coaches (266 female; 34.6%) from 3 sports (basketball, volleyball, soccer) completed an anonymous online questionnaire regarding their team's sport volume and their knowledge, attitudes, and beliefs regarding sport specialization. Coaches were eligible to participate if they had served as the head or assistant coach of a high school sport team or high school-aged club sport team in the past 12 months.

RESULTS

Overall, 64.6% (n = 497) were coaches of a high school team, and 35.4% (n = 272) were coaches of a club team with high school-aged athletes. Club coaches' teams played more months out of the year and took more overnight trips for competitions than high school coaches' teams but participated in fewer hours per week of practices or competitions during their season. There were no differences between club and high school coaches in tracking their athletes' sport volume, with most coaches in both settings reporting that they do not track the amount of time that their athletes participate in other sports.

CONCLUSION

Significant differences in sport participation volume exist between the teams of high school and club coaches.

Elasticity of the pronator teres muscle in youth baseball players with elbow injuries: evaluation using ultrasound strain elastography

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.

Can We Reduce the Epidemic of Elbow Injuries in Youth Throwers?

As participation in youth sports continues to increase across the nation, more adolescents are participating in Little League baseball in the United States than ever before. Accompanying this increased participation is an epidemic of upper extremity injuries in young throwers. In this Viewpoint, the authors discuss the impetus behind the youth thrower elbow injury epidemic and how to best evaluate these patients. J Orthop Sports Phys Ther 2018;48(5):354-357. doi:10.2519/jospt.2018.0607.

Variation in stress distribution patterns across the radial head fovea in osteochondritis dissecans: predictive factors in radiographic findings

BACKGROUND

Predictive factors for the development of osteoarthritis in adolescent osteochondritis dissecans (OCD) of the humeral capitellum remain unclear. The objectives of this study were to assess subchondral bone density in the radial head fovea of patients with OCD and to evaluate stress distribution in the radiocapitellar joint. The relationship between radiologic classification and stress distribution, according to multivariate ordinal regression analysis, was also investigated.

METHODS

Computed tomography (CT) imaging data from 54 male patients with OCD (mean age, 13.1 years) were collected. Stress in the radial head fovea was measured using CT osteoabsorptiometry. A stress map was constructed and divided into 4 sections, and percentages of high-density regions in each section were quantitatively analyzed. Multivariate ordinal regression analyses were performed of bone density, incorporating the stage, location, and size of the OCD lesion and the presence of medial elbow disturbance in the radiographic images.

RESULTS

The percentage of high-density area in the anteromedial, posteromedial, and the anterolateral sections of the radial head fovea were significantly increased compared with the posterolateral section. Multivariate ordinal regression analysis revealed that the location and size of the lesion and a history of excessive valgus stress were associated with imbalances in the radial head fovea.

CONCLUSIONS

When the OCD lesion is large and located laterally and a medial epicondyle disturbance is apparent on radiographs, the risk for developing advanced radiocapitellar osteoarthritis should be considered. These findings can be useful in the decision-making process for treating OCD.

Shoulder MRI Abnormalities in Asymptomatic Little League Baseball Players

Background:

Youth baseball is extremely popular in the United States, but it has been associated with shoulder pain and injury. The incidence of shoulder abnormalities in this athletic population has yet to be defined.

Purpose:

To examine abnormalities noted on magnetic resonance imaging (MRI) in the shoulders of asymptomatic Little League baseball players and to correlate these findings with the players’ throwing history and physical examinations.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 23 Little League baseball players aged 10 to 12 years were recruited. All players underwent a comprehensive physical examination and responded to a questionnaire addressing their playing history and any arm or shoulder pain. Bilateral shoulder MRIs were performed and read in a blinded manner by 2 radiologists. Responses on the questionnaire and physical examination findings were compared between participants with and without positive MRI findings through use of chi-square test and analysis of variance.

Results:

The dominant arm was 8.5 times more likely to have an abnormality on MRI compared with the nondominant arm. In all, 12 players (52%) had 17 positive MRI findings in their throwing shoulder that were not present in their nondominant shoulder. These findings included edema or widening of the proximal humeral physis (n = 5), labral tear (n = 4), partial rotator thickness tear (n = 4), acromioclavicular joint abnormality (n = 2), subacromial bursitis (n = 1), and cystic change of the greater tuberosity (n = 1). Two primary risk factors were associated with an abnormal MRI: year-round play and single-sport athletes focusing solely on baseball (P < .05). Players with no risk factors, 1 risk factor, and both risk factors had a 25%, 71%, and 100% chance, respectively, of having an abnormal MRI. A majority of players (61%) had previously experienced shoulder pain, especially pitchers throwing curveballs and sliders (P < .05), but this was not associated with an abnormal MRI.

Conclusion:

Abnormalities seen on MRI involving the shoulder are common in Little League baseball players, especially those who are single-sport athletes playing year-round.

An Epidemiological Comparison of Elbow Injuries Among United States High School Baseball and Softball Players, 2005-2006 Through 2014-2015

Background:

Pitching is a common mechanism of injury in baseball, with known risk factors for elbow injuries among adolescent pitchers.

Hypothesis:

Elbow injury rates and mechanisms will differ between high school baseball and softball players.

Study Design:

Descriptive epidemiology study.

Level of Evidence:

Level 3.

Methods:

Baseball- and softball-related injury data from the 2005-2006 through 2014-2015 academic years were collected from the High School Reporting Information Online (RIO) Internet-based data collection tool. Athlete-exposure (AE) and injury data were collected by certified athletic trainers. Rate ratios (RRs) were calculated comparing injury rates in the 2 populations. Injury proportion ratios (IPRs) comparing elbow injuries in pitchers and nonpitchers were calculated as the proportion of all elbow injuries in pitchers divided by the proportion of all elbow injuries in nonpitchers.

Results:

A total of 214 elbow injuries in male baseball players occurred over 2,327,774 AEs, for an overall elbow injury rate of 0.92 per 10,000 AEs. A total of 75 elbow injuries were reported in female softball players over 1,731,644 AEs, for an overall rate of 0.43 per 10,000 AEs. The rate of elbow injury was significantly higher for baseball than softball (RR, 2.12; 95% CI, 1.64-2.77). A significantly greater proportion of elbow injuries in baseball were pitching-related compared with those from softball, with 50.2% occurring while pitching in baseball versus 11.0% in softball (IPR, 4.58; 95% CI, 2.35-8.93). If all injuries occurring during pitching were removed from both sports, the difference in elbow injury rate for baseball and softball would no longer be significant (RR, 1.19; 95% CI, 0.88-1.62).

Conclusion:

The rate of elbow injuries is significantly higher in baseball than softball. This is attributable to differences in rates of pitching-related injuries between these 2 groups.

Clinical Relevance:

These results demonstrate that overhand pitching increases risk of elbow injury in high school athletes.

Trends in Sports-Related Elbow Ulnar Collateral Ligament Injuries

BACKGROUND

Elbow ulnar collateral ligament (UCL) injuries are common, particularly in adolescent athletes playing overhead sports. While the incidence and outcomes of surgical UCL injuries are well documented, the nonsurgical UCL injury patterns and injury management in this population are not yet known.

PURPOSE/HYPOTHESIS

The purpose of this study was to retrospectively assess the injury severity and subsequent management of UCL injuries among competitive athletes aged 11 to 22 years. We hypothesized that nonsurgical UCL injuries would occur more frequently in younger athletes compared with older athletes.

STUDY DESIGN

Descriptive epidemiological study.

METHODS

Electronic medical records (using International Classification of Diseases, 9th Revision and 10th Revision and Current Procedural Terminology codes) and keyword searches were used to identify all patients with sports-related UCL injuries between January 2000 and April 2016. A total of 136 records were included. Patients were stratified into 3 age brackets (age 11-13 years, n = 17; age 14-16 years, n = 49; age 17-22 years, n = 70). There were no prior elbow surgical interventions. The main outcome measures included the frequency and severity of UCL injuries and injury management (surgical, nonsurgical). Independent variables included age, UCL injuries per year, and sport classification.

RESULTS

There were 53 surgical and 83 nonsurgical UCL injuries. The number of nonsurgical cases increased 9-fold from 2000-2008 to 2009-2016. The UCL injuries were distributed as follows: 60 sprains, 39 partial tears, 36 ruptures, and 1 rerupture. Moreover, 7% of sprains, 51% of partial tears, and 78% of ruptures underwent UCL reconstruction. Nonsurgical management was most common in the youngest athletes (age 11-13 years, 100.0% of total injuries; age 14-16 years, 71.4% of total injuries; and age 17-22 years, 44.3% of total injuries) (P = .007). UCL injury volume was most commonly associated with javelin (odds ratio, 6.69; 95% CI, 0.72-61.62; P = .07) and baseball (odds ratio, 1.55; 95% CI, 0.69-3.51; P = .32).

CONCLUSION

Younger athletes sustained less severe UCL injuries more often than older athletes. Participation in javelin and baseball was associated with a greater likelihood of UCL injuries based on our dataset. This is the first study to provide data on the volume of nonsurgical UCL injuries among athletes in various sports.