Epidemiologic Comparison of Pitching Mechanics, Pitch Type, and Pitch Counts Among Healthy Pitchers at Various Levels of Youth Competition

Elbow Flexion Excursion: Intra- and Inter-Throwing Arm Kinetic Evaluations in High School and Professional Baseball Pitchers

BACKGROUND

Elbow flexion at stagnant time points of the pitch has been associated with increased elbow varus torque (EVT) and elbow injury history.

PURPOSE

To determine how elbow flexion angle throughout the pitch (excursion) between individual pitchers and a cohort of pitchers influences throwing arm kinetics in high school (HS) and professional (PRO) pitchers.

STUDY DESIGN

Descriptive laboratory study.

METHODS

HS (n = 59) and PRO (n = 288) pitchers were instructed to throw 8 to 12 fastball pitches evaluated with 3-dimensional motion capture system (480 Hz). Linear regression models were developed to examine the association between elbow flexion excursion with ball velocity and throwing arm kinetics. An intrapitcher analysis utilizing a linear mixed model was also used, introducing pitchers as a random effect.

RESULTS

The mean elbow flexion excursion was significantly greater for HS (70° ± 22°) compared with PRO (63° ± 21°) pitchers (P < .001), while the mean normalized EVT was significantly less for HS pitchers (3.9% ± 0.7% vs 4.8% ± 0.8% body weight [BW] × body height; P < .001). For every 1 SD increase in elbow excursion, ball velocity increased by 0.8 to 1.0 m/s (approximately 2 mph) for intra- and interanalyses (P max = 0.006; β = 0.31-0.39) for HS pitchers, while it increased by only 0.2 to 0.4 m/s (<1 mph) for PRO pitchers (P max = 0.016; β = 0.10-0.17). EVT increased by 0.34 to 0.40 SD for every 1 SD increase in elbow excursion for intra- and interanalyses for HS pitchers and by 0.13 to 0.22 SD for PRO pitchers. Elbow medial force increased by 1.9% to 2.3% BW for every 1 SD increase in elbow excursion for intra- and interanalyses of HS pitchers (β = 0.35-0.44) and by 1.4% to 1.7% BW increase for PRO pitchers (β = 0.23-0.27).

CONCLUSION

PRO pitchers have decreased elbow flexion excursion compared with HS pitchers. This may be an advantageous mechanism by which to minimize throwing arm kinetics, including EVT and elbow medial force, supported by both intra- and interpitcher analyses. Ball velocity benefits with increased elbow excursion were marginal for both cohorts.

CLINICAL RELEVANCE

In support of previous literature suggesting that increased elbow flexion at later portions of the pitch is associated with increased EVT and injury history, this study further substantiates that this may be deleterious kinematics to baseball pitchers.

Current State of Baseball Interval Throwing Programs: A Systematic Review of Content, Structure, and Variability of Published Throwing Programs

CONTEXT

There is need for an up-to-date comprehensive review of baseball interval throwing programs in the literature.

OBJECTIVE

To (1) understand the origin and basis of interval throwing programs; (2) evaluate the content of programs in the peer-reviewed literature including target audience, initiation criteria, throwing specifics, arm care, and performance evaluation metrics; (3) classify these variables as well defined, ambiguous, or missing; and (4) analyze variability in key aspects including starting criteria, length, progression, and completion criteria.

DATA SOURCES

Medline, Embase, Cochrane Reviews, Web of Science, and ScopusStudy Selection:The full text of studies, in English, had to be available. Included studies had to contain a complete interval throwing program designed for baseball players.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 4.

DATA EXTRACTION

Initial screening was conducted based on article title and abstract. Full text of the remaining articles was evaluated for fulfillment of inclusion criteria.

RESULTS

Nine studies initially met inclusion criteria. The programs' comprehensiveness was poor, with a mean Interval Throwing Program Checklist score of 20 (range 14-23) on a scale of 0 to 30. There were a variety of components, including progressive long toss, weighted ball, and throwing mechanics exercises. The programs identified had significant heterogeneity in duration, intensity, progression, and focus. Overall, there was a significant lack of attempts at validation or formal study of efficacy for published throwing programs.

CONCLUSION

Current published interval throwing programs are mostly variations of an original program published many years ago and were based on principles of progressive loading with pain as sign of injury that should be monitored carefully. However, these programs have minimal clinical validation and objective measures to quantify their effectiveness. This work identifies several limitations in the current literature and can serve as a foundation for future development of evidence-based interval throwing programs.

Shoulder and Elbow Symptoms in Dutch High School Baseball Pitchers: Results of a Two-Season Prospective Study

CONTEXT

Baseball pitching requires fast and coordinated motions of the whole body to reach high ball speeds, putting considerable strain on the musculoskeletal system, particularly the shoulder and elbow.

OBJECTIVE

To describe musculoskeletal symptoms and the functional status of the shoulder and elbow in male high school baseball pitchers.

DESIGN

Descriptive epidemiology study.

SETTING

Dutch baseball talent academies.

PATIENTS OR OTHER PARTICIPANTS

One hundred twenty-five male high school baseball pitchers aged 12 to 18 years who participated in 1 of the 6 Dutch baseball talent academies and the Dutch National U-18 team were recruited and enrolled.

MAIN OUTCOME MEASURE(S)

Musculoskeletal symptoms, functional status of the shoulder and elbow were registered for each player every 6 months over 2 consecutive baseball seasons through self-assessment questionnaires, including the Kerlan-Jobe Orthopaedic Clinic (KJOC) and the Western Ontario Shoulder Instability Index (WOSI) questionnaires.

RESULTS

Five hundred seventy musculoskeletal (MSS) symptoms in 93 of the 125 players were reported. The average 6-month prevalence for symptoms of the throwing shoulder was 37% (95% CI = 33%-41%), and for the elbow 37% (95% CI = 31%-42%), followed by the lower back with 36% (95% CI = 26%-45%). The baseball pitchers who experienced only shoulder symptoms had an average KJOC score of 80.0 (95% CI = 75.3-84.7) points, whereas those with only elbow symptoms reported a score of 90.2 (95% CI = 89.2-95.3). On the WOSI questionnaire, baseball pitchers scored an average of 421.2 (95% CI = 200.1-642.4) points.

CONCLUSIONS

In a cohort of Dutch high school baseball pitchers, one-third reported shoulder and elbow symptoms on the throwing side, with reduced functional status and lower back symptoms. Future efforts should focus on developing preventive strategies through early symptom detection, aiming to prevent symptom progression and, ultimately, the development of severe injuries.

Hip Strength and Pitching Biomechanics in Adolescent Baseball Pitchers

CONTEXT

Hip strength may influence the energy flow through the kinematic chain during baseball pitching, affecting athlete performance as well as the risk for injury.

OBJECTIVE

To identify associations between hip strength and pitching biomechanics in adolescent baseball pitchers during 3 key events of the pitching cycle.

DESIGN

Cross-sectional study.

SETTING

Biomechanics laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 26 adolescent male baseball pitchers (age = 16.1 ± 0.8 years, height = 184.29 ± 5.5 cm, mass = 77.5 ± 8.5 kg).

MAIN OUTCOME MEASURE(S)

The main outcome measure was hip strength (external rotation, internal rotation, flexion, abduction, adduction, and extension). After strength measurements were acquired, motion capture was used to obtain a full-body biomechanical analysis at 3 events during the pitching cycle (foot contact, maximal external rotation, and ball release). We then evaluated these values for associations between hip strength and pitching biomechanics. Scatterplots were examined for linearity to identify an appropriate correlation test. The associations were linear; thus, 2-tailed Pearson correlation coefficients were used to determine correlations between biomechanical metrics. An α level of .01 was chosen.

RESULTS

Ten strong correlations were found between pitching biomechanics and hip strength: 8 correlations between hip strength and kinematics at key points during the pitch and 2 correlations of hip strength with peak elbow-varus torque.

CONCLUSIONS

Several correlations were noted between lower extremity strength and pitching biomechanics. This information provides data that may be used to improve performance or reduce injury (or both) in pitchers. Increased hip strength in adolescent pitchers may both improve performance and decrease the risk of injury.

Kinetic and kinematic comparisons in high school pitchers with low and high pitch location consistency

BACKGROUND

Although ball velocity has often been associated with increased kinetics at the upper extremity and risk of injury in youth and adolescent pitchers, it is unclear if the performance metric pitch location consistency has any positive or negative associations with pitching kinetics.

METHODS

High school pitchers (n = 59) pitched 8-12 fastballs using 3D motion capture (480 Hz). Pitchers were divided into high-consistency (HiCon) and low-consistency (LoCon) groups based on the absolute center deviation of each pitcher's pitch to the center of the pitcher's mean pitch location. Ninety-five percent confidence ellipses with major and minor radii were constructed, and kinematics and kinetics were compared between groups.

RESULTS

Compared with LoCon pitchers, HiCon pitchers had decreased lead hip flexion at elbow extension (40° ± 12° vs. 52° ± 13°, respectively, P = .008), and at foot contact, decreased back hip extension (-1° ± 10° vs. -10° ± 13°, respectively, P = .038) and increased back hip internal rotation (9° ± 15° vs. -2° ± 15°, respectively, P = .043). LoCon pitchers achieved maximum lead hip flexion earlier in the pitch (61.3% ± 23.2% vs. 75.8% ± 15.1%, respectively, P = .039). A multiregression model predicted 0.49 of variance in pitch location consistency using kinematic inputs.

DISCUSSSION AND CONCLUSION

Pitchers who differ in pitch location consistency outcomes do not appear to demonstrate physiologically unsafe kinematics. High school pitchers who strive for improved pitch consistency can consider adjusting parameters of hip kinematics during early portions of the pitch.

Editorial Commentary: Rehabilitation of the Overhead Throwing Athlete Requires Supervision of Mechanics, Velocity, and Total Workload

Rehabilitation of the baseball athlete requires understanding of the unique injury profile of throwers and the pathologic conditions specific to the throwing motion. To optimize performance recovery, consideration must be given to age of the athlete, mechanics of throwing, velocity or effort of the throw, and total workload over time, with careful attention to minimize spikes in workload. Rehabilitation success of junior throwers is variable and likely relates to lack of high-level supervised throwing programs and mechanical analysis. Given the epidemic of elbow injuries in our younger athletes, efforts to standardize rehabilitation metrics for progression will be of significant value.

Adolescent Baseball Pitchers With Ulnar Collateral Ligament Tears Exhibit a High Proportion of Partial Tears

BACKGROUND

Ulnar collateral ligament (UCL) tears in the throwing elbow are classified according to grade and location using magnetic resonance arthrography (MRA). However, the frequency of each tear type and the association to age, competition level, and radiographic findings in adolescent baseball pitchers are unknown.

PURPOSES

The primary purpose of this study was to use MRA to characterize the severity, location, and UCL tear type in adolescent pitchers. The second aim was to describe the relationship between the UCL tear type and age, competition level, and plain radiographic findings.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Records of adolescent pitchers with a UCL tear treated by the senior author between 2007 and 2016 were retrospectively reviewed. MRA scans were reviewed and tears were classified according to the Joyner-Andrews classification. Low-grade partial tears are classified as type I, high-grade partial tears as type II, complete full-thickness tears as type III, and tear pathology in >1 region in the UCL as type IV. Each type of tear also has a location designated at the midsubstance, ulna (U), or humerus (H). Patient characteristics, competition level, and associated plain radiographic abnormalities were recorded. Univariate analyses were performed to examine the relationships between tear types and age, competition level, and plain radiographic findings.

RESULTS

A total of 200 adolescent pitchers (mean ± SD age, 17.2 ± 1.5 years) with MRA scans were reviewed. Type II-H (n = 62), type II-U (n = 51), and type III-U (n = 28) were the most common tear types observed. Type II tears comprised 64.5% of adolescent UCL tears, with type II-H being the most common. Plain radiographs were abnormal in 32% of patients, with calcifications (10.5%) and olecranon osteophytes (12.5%) being the most common findings. There were no significant relationships between tear type and age (P = .25), competition level (P = .23), or radiographic abnormalities (P = .75).

CONCLUSION

Humeral-sided high-grade partial tears were the most common tear type in adolescent pitchers. There was no relationship between UCL tear type and age competition level, and plain radiographic abnormalities.

Relationships between Hip Flexibility and Pitching Biomechanics in Adolescent Baseball Pitchers

CONTEXT

Inadequate hip active range of motion (AROM) may stifle the energy flow through the kinematic chain and decrease pitching performance while increasing the risk for pitcher injury.

OBJECTIVE

To examine the relationship of hip AROM and pitching biomechanics during a fastball pitch in adolescent baseball pitchers.

DESIGN

Cross-Sectional study.

SETTING

Biomechanics laboratory.

PARTICIPANTS

A voluntary sample of 21 adolescent baseball pitchers (16.1 ± 0.8 yrs.; 183.9 ± 5.2 cm; 77.9 ± 8.3 kg). Main Outcome Measure (s): Bilateral hip internal rotation (IR), external rotation (ER), flexion, extension, and abduction AROM were measured. Three-dimensional biomechanics were assessed as participants threw from an indoor pitching mound to a strike zone net at regulation distance. Pearson correlation coefficients were used to determine correlations between hip AROM and biomechanical metrics.

RESULTS

Statistically significant negative correlations were found at foot contact between back hip ER AROM and back hip abduction angle (p=0.030, r=-0.474), back hip ER AROM and torso rotation angle (p=0.032, r=-0.468),and back hip abduction AROM and lead hip abduction angle (p=0.037, r=-0.458). Back hip extension AROM was positively correlated with increased stride length (p=0.043, r=0.446). Lead hip abduction AROM was also positively correlated with normalized elbow varus torque (p=0.034, r=0.464).

CONCLUSIONS

There were several relationships between hip AROM and biomechanical variables during the pitching motion. The findings support the influence hip AROM can have on pitching biomechanics. Overall, greater movement at the hips allows for the kinematic chain to work at its maximal efficiency, increasing pitch velocity potential.

Lower Extremity Biomechanics Predicts Major League Baseball Player Performance

Background:

Although lower extremity biomechanics has been correlated with traditional metrics among baseball players, its association with advanced statistical metrics has not been evaluated.

Purpose:

To establish normative biomechanical parameters during the countermovement jump (CMJ) among Major League Baseball (MLB) players and evaluate the relationship between CMJ-developed algorithms and advanced statistical metrics.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

MLB players in 2 professional organizations performed the CMJ at the beginning of each baseball season from 2013 to 2017. We collected ground-reaction force data including the eccentric rate of force development (“load”), concentric vertical force (“explode”), and concentric vertical impulse (“drive”) as well as the Sparta Score. The advanced statistical metrics from each baseball season (eg, fielding independent pitching [FIP], weighted stolen base runs [wSB], and weighted on-base average) were also gathered for the study participants. The minimal detectable change (MDC) was calculated for each CMJ variable to establish normative parameters. Pearson coefficient analysis and regression trees were used to evaluate associations between CMJ data and advanced statistical metrics for the players.

Results:

A total of 151 pitchers and 138 batters were included in the final analysis. The MDC for “load,” “explode,” “drive,” and the Sparta Score was 10.3, 8.1, 8.7, and 4.6, respectively, and all demonstrated good reliability (intraclass correlation coefficient > 0.75). There was a weak but statistically significant correlation between the Sparta Score and wSB (r = 0.23; P = .007); however, there were no significant correlations with any other advanced metrics. Regression trees demonstrated superior FIP with higher Sparta Scores in older pitchers compared with younger pitchers.

Conclusion:

There was a positive but weak correlation between the Sparta Score and base-stealing performance among professional baseball players. Additionally, older pitchers with a higher Sparta Score had statistically superior FIP compared with younger pitchers with a similar Sparta Score after adjusting for age.

A New Method for Evaluating Pelvic and Trunk Rotational Pitching Mechanics: From Qualitative to Quantitative Approaches

The purpose of this study was to build on existing qualitative to quantitative approaches to develop a new quantitative method for evaluating pelvic and trunk rotational pitching mechanics. Thirty pitchers were divided into two groups ("Pattern1": closed "hip-to-shoulder separation"; "Pattern2": open "hip-to-shoulder separation"). Several parameters were analyzed. Higher ball speeds were found in group of Pattern1, four key characteristics of which were identified. Based on the results, a new evaluation method was developed. Pelvic and trunk rotational mechanics were classified into four types. Type1 (proper mechanics) enabled significantly higher ball speed than the other three types and was thought to involve proper energy transfer from the stride foot to the throwing upper limb. Types 2-4, however, were regarded as "improper mechanics", which could result in slower ball speeds and less efficient energy transfer. A qualitative approach, based on "expert opinion", can specify optimal pelvis and trunk rotational mechanics. However, quantitative analysis is more precise in identifying three improper types of pelvis and trunk rotational mechanics. Furthermore, special programs, such as core strengthening and flexibility training, can be developed for various improper practices in order to improve pitching mechanics.

Interaction Between Age and Change in Velocity During a Baseball Training Program

Background:

Pitching velocity is one of the most important metrics used to evaluate a baseball pitcher’s effectiveness. The relationship between age and pitching velocity after a lighter ball baseball training program has not been determined.

Purpose/Hypothesis:

The purpose of this study was to examine the relationship between age and pitching velocity after a lighter ball baseball training program. We hypothesized that pitching velocity would significantly increase in all adolescent age groups after a lighter baseball training program, without a significant difference in magnitude of increase based on age.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Baseball pitchers aged 10 to 17 years who completed a 15-week training program focused on pitching mechanics and velocity improvement were included in this study. Pitchers were split into 3 groups based on age (group 1, 10-12 years; group 2, 13-14 years; group 3, 15-17 years), and each group trained independently. Pitch velocity was assessed at 4 time points (sessions 3, 10, 17, and 25). Mean, maximum, and mean change in pitch velocity between sessions were compared by age group.

Results:

A total of 32 male baseball pitchers were included in the analysis. Mean/maximum velocity increased in all 3 age groups: 3.4/4.8 mph in group 1, 5.3/5.5 mph in group 2, and 5.3/5.2 mph in group 3. While mean percentage change in pitch velocity increased in all 3 age groups (group 1, 6.5%; group 2, 8.3%; group 3, 7.6%), the magnitude of change was not significantly different among age groups. Program session number had a significant effect on mean and maximum velocity, with higher mean and maximum velocity seen at later sessions in the training program (P = .018). There was no interaction between age and program session within either mean or maximum velocity (P = .316 and .572, respectively).

Conclusion:

Age had no significant effect on the magnitude of increase in maximum or mean baseball pitch velocity during a velocity and mechanics training program in adolescent males.

Current Workload Recommendations in Baseball Pitchers: A Systematic Review

BACKGROUND

Several recommendations have been made regarding pitch counts and workload for baseball players of different levels, including Little League, high school, collegiate, and professional baseball. However, little consensus is found in the literature regarding the scientific basis for many of these recommendations.

PURPOSE

The primary purpose of this study was to summarize the evidence regarding immediate and long-term musculoskeletal responses to increasing pitching workload in baseball pitchers of all levels. A secondary purpose of this review was to evaluate the extent to which workload influences injury and/or performance in baseball pitchers.

STUDY DESIGN

Systematic review.

METHODS

We performed a systematic search in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines for studies addressing physiologic and/or pathologic musculoskeletal changes in response to a quantifiable pitching workload. We included studies examining the effects of pitching workload on performance, injury rate, and musculoskeletal changes in Little League, high school, collegiate, and professional baseball players.

RESULTS

We identified 28 studies that met our inclusion and exclusion criteria: 16 studies regarding Little League and high school pitchers and 12 studies regarding collegiate and professional pitchers. The current evidence presented suggests that increased pitching workload may be associated with an increased risk of pain, injury, and arm fatigue in Little League and high school pitchers. However, little consensus was found in the literature regarding the association between pitching workload and physiologic or pathologic changes in collegiate and professional pitchers.

CONCLUSION

Evidence, although limited, suggests the use of pitch counts to decrease injury rates and pain in Little League and high school baseball pitchers. However, further research must be performed to determine the appropriate number of pitches (or throws) for players of different ages. This systematic review reported conflicting evidence regarding the use of pitch counts in college and professional baseball. Future high-quality research is required to determine the role, if any, of pitch counts for collegiate and professional pitchers.

Correlation between playing position, elbow physical findings and elbow pain in elementary school baseball players: Results of a multi-regional study in Japan

BACKGROUND

Elbow injuries are common in young baseball players and evaluating the characteristics of young baseball players in a large-scale population is necessary. However, few studies have compared playing position, length of baseball experience, physical findings, and elbow pain in young baseball players. This retrospective multi-regional cohort study sought to document the physical findings at the elbow in Japanese elementary school baseball players and to examine the relationship between playing position, length of baseball experience, physical findings at the elbow, and elbow pain.

METHODS

In 2014, 720 fifth-grade baseball players from four regions in Japan were invited to participate in a questionnaire survey and undergo physical examination to obtain data on position played, length of baseball experience, presence of elbow pain, and physical findings at the elbow, including range of motion, tenderness, and valgus stress test results. Potential risk factors associated with elbow pain and correlations between physical findings and playing position, length of baseball experience, and elbow pain were investigated.

RESULTS

The 720 subjects had a mean age of 10.4 years and 29.4% reported having experienced elbow pain for ≥1 week. Risk factors for elbow pain included playing pitcher and catcher, playing pitcher and fielder, and length of baseball experience. The most frequent finding was limitation of flexion (21.1%) followed by tenderness of the medial epicondyle (18.3%) and a positive valgus stress test (14.3%). These three findings were also significantly associated with elbow pain. Elbow extension was limited in 14.9% of subjects but there was no correlation with length of baseball experience or elbow pain.

CONCLUSIONS

Our data show that elementary school baseball players who experienced elbow pain are likely to have valgus stress overload. Elbow pain might be prevented by not playing pitcher and catcher.

Biomechanical Evaluation of a Modified Internal Brace Construct for the Treatment of Ulnar Collateral Ligament Injuries

Background:

Ulnar collateral ligament (UCL) repair augmented with the “internal brace” construct for the management of acute UCL injuries has recently garnered increasing interest from the sports medicine community. One concern with this technique is excessive bone loss at the sublime tubercle, should revision UCL reconstruction be required. In an effort to preserve the bony architecture of the sublime tubercle, an alternative internal brace construct is proposed and biomechanically compared with the gold standard UCL reconstruction.

Hypothesis:

The internal brace repair construct will restore valgus laxity and rotation to its native state and demonstrate comparable load-to-failure characteristics with the 3-strand reconstruction technique.

Study Design:

Controlled laboratory study.

Methods:

For this study, 8 matched pairs of fresh-frozen cadaveric elbows were randomized to undergo either UCL reconstruction with the 3-ply docking technique or UCL repair with a novel internal brace construct focused on augmenting the posterior band of the anterior bundle of the ligament (modified repair-IB technique). Valgus laxity and rotation measurements were quantified through use of a MicroScribe 3DLX digitizer at various flexion angles of the native ligament, transected ligament, and repaired or reconstructed ligament. Laxity testing was performed from maximum extension to 120° of flexion. Each specimen was then loaded to failure, and the method of failure was recorded.

Results:

Valgus laxity was restored to the intact state at all degrees of elbow flexion with the modified repair-IB technique, and rotation was restored to the intact state at both full extension and 30°. In the reconstruction group, valgus laxity was not restored to the intact state at either full extension or 30° of flexion (P < .001 and P = .004, respectively). Laxity was restored at 60° of flexion, but the elbow was overconstrained at 90° and 120° of flexion (P = .027 and P = .003, respectively). In load-to-failure testing, the reconstruction group demonstrated significantly greater yield torque (19.1 vs 9.0 N·m; P < .005), yield angle (10.2° vs 5.4°; P = .007), and ultimate torque (23.9 vs 17.6 N·m; P = .039).

Conclusion:

UCL repair with posterior band internal bracing was able to restore valgus laxity and rotation to the native state. The construct exhibited lower load-to-failure characteristics when compared with the reconstruction technique.

Clinical Relevance:

In selected patients with acute, avulsion-type UCL injuries, ligament repair with posterior band internal bracing is a viable alternative surgical option that, by preserving bone at the sublime tubercle, may decrease the complexity of future revision procedures.

A Clinician's Guide to Analysis of the Pitching Motion

PURPOSE OF REVIEW

This review examines recent literature regarding analysis of the throwing motion in baseball players and how modern technology may be used to predict or prevent injury.

RECENT FINDINGS

Proper throwing technique is vitally important to prevent injury and it is easier to correct poor mechanics prior to foot strike. Recent findings suggest that the inverted-W position may not lead to an increased risk of injury, but incorrect trunk or pelvis rotation does. Three-dimensional motion analysis in a laboratory setting is most commonly used to evaluate the throwing motion, but it does not allow for assessment in real game scenarios. Wearable monitors allow for this and have proven to reliably assess pitching workload, kinematics, and kinetics. Injuries in youth baseball pitchers have increased along with the trend towards more single sport specialization. To prevent injury, assessment of a pitcher's throwing motion should be performed early to prevent development of poor mechanics. Classically, three-dimensional motion analysis has been used to evaluate throwing mechanics and is considered the gold standard. Newer technology, such as wearable monitors, may provide an alternative and allow for assessment during actual competition.

Elbow flexion angle during graft fixation for ulnar collateral ligament reconstruction: a systematic review of outcomes and complications

BACKGROUND

The ulnar collateral ligament (UCL) of the elbow is commonly injured in overhead athletes, especially baseball pitchers. UCL reconstruction has shown good outcomes regarding return to play, but revision rates are on the rise. This review was conducted to determine the effect of elbow flexion angle during graft fixation on outcomes and complications after UCL reconstruction.

METHODS

MEDLINE, Embase, and PubMed were searched from database inception to November 16, 2017. Patient demographics, surgical technique, graft selection, outcomes, and complications were extracted from the included studies. The quality of each study was assessed in duplicate with the Methodological Index for Non-Randomized Studies criteria. Descriptive statistics are presented.

RESULTS

Six studies, with a total of 1168 patients, were included, and all were case series. Excellent Conway scores were present in 83.8% of patients for the 0° to 30° group and in 91.1% of patients for the 45° to 70° group, with no significant differences in return to play between the groups. The rate of revision UCL reconstruction was significantly higher with graft fixation at 0° to 30° (1.4%) compared with fixation at 45° to 70° (0%; P < .01).

CONCLUSIONS

Elbow flexion angle during graft fixation may not influence return to the same or higher level of competition but appears to influence the need for a revision after UCL reconstruction. However, the available current evidence possesses a high degree of fragility, and further studies are needed with objective measurements to determine the optimal elbow flexion angle for graft fixation.

Increased pitch velocity and workload are common risk factors for ulnar collateral ligament injury in baseball players: a systematic review

Importance

Ulnar collateral ligament (UCL) injuries commonly occur in baseball players. Strategies for injury prevention have long been accepted without clinical data informing which risk factors lead to serious injury.

Objective

The objective of this study was to systematically review the impact of various pitching-related risk factors for UCL injury in baseball players from all levels of play.

Evidence review

The electronic databases MEDLINE, EMBASE and PubMed were systematically searched until 4 March 2018, and pertinent data were abstracted by two independent reviewers. Search terms included ‘ulnar collateral ligament’, ‘medial ulnar collateral ligament’, ‘Tommy John’, ‘risk’ and ‘association’. Inclusion criteria were English-language studies, level of evidence I–IV and studies reporting risk factors for UCL injury of the elbow in baseball players. Study quality was assessed using the methodological index for non-randomised studies (MINORS) criteria. The results are presented in a narrative summary.

Findings

Pitching practices (workload and pitch characteristics) were reported in 9/15 studies. Specifically, three of four studies (n=1810) reported increased pitch workload as a risk factor for native UCL injury (p<0.001 to 0.02). The most common pitch characteristic reported was pitch velocity with four of five studies showing increased velocity being significantly associated with native UCL injury (p<0.01 to 0.02). Biomechanical risk factors reported were increased humeral retrotorsion (two studies; n=324), poor lower extremity and trunk balance (one study; n=42) and loss of total arc of shoulder motion (two studies; n=118), all significantly associated with UCL injury (p<0.0001 to 0.05). One of three studies assessing pitch workload as a risk factor for re-rupture of UCL reconstruction found a significant association (p<0.01).

Conclusions and relevance

Pitching practices, reflected by increased pitch workload and velocity, were most commonly associated with UCL injury; however, the definition of workload (number of pitches per game, inning or season) was inconsistently reported. Biomechanical risk factors were less commonly reported and lack sufficient evidence to recommend preventative strategies. More quality data is needed to refine the current recommendations for injury prevention in baseball players.

Level of evidence

III.

Upper Extremity Range of Motion and Pitching Profile of Baseball Pitchers in Japan

BACKGROUND

Shoulder range of motion and pitch count in baseball pitchers have been linked to pitching-related upper extremity injury.

PURPOSE

To investigate upper extremity range of motion and pitching profiles in baseball pitchers in Japan as well as to make a comparison between injured and noninjured pitchers.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Forty-one Little League to college-level baseball pitchers were measured for bilateral shoulder and elbow range of motion, including shoulder internal rotation (IR), external rotation (ER), shoulder horizontal adduction (HAD), and elbow extension (EXT). They were also asked to answer a simple questionnaire regarding their past pitching-related medical history and pitching profile. Additionally, 28 participants with baseball-related upper extremity injuries (injury group) were compared with 13 participants without injury (no-injury group) for the same parameters. Collected data were analyzed using analysis of variance.

RESULTS

Significant limb differences (dominant vs nondominant side) were noted for ER (117.2° vs 109.8°, P = .02), IR (53.5° vs 61.9°, P = .007), HAD (28.3° vs 32.8°, P = .03), and EXT (1.0° vs 4.6°, P = .01). A significant between-group difference (injury vs no-injury group) was observed for IR in both the dominant (55.4° vs 45.6°, P = .03) and nondominant shoulder (65.3° vs 55.0°, P = .01). Participants in the injury group pitched more games in a season and more innings per game started.

CONCLUSION

Japanese baseball pitchers displayed adaptive changes in upper extremity range of motion similar to American pitchers when compared bilaterally. Injured pitchers exhibited greater IR range of motion in their pitching arm compared with noninjured pitchers.

Auld Lang Syne: A New Year Brings Awards and a New Cover

"Auld Lang Syne," a traditional poem used to welcome the New Year, asks rhetorically, "Should old acquaintance be forgot, and never brought to mind?" At Arthroscopy, the answer is a resounding no. We view January as an opportunity to celebrate the abundance and excellence of research published in Arthroscopy. This year, we have decided to spread our applause, approval, and appreciation to recognize both award winners and runners-up, whose distinction in research epitomizes the bounty that is Arthroscopy. In addition, we proudly introduce a new cover.

Editorial Commentary: Pitching Should Come With a Warning Label

Pitching is not without risk of overuse injuries. Pitch counts have been instituted to reduce the risk, but Riff et al.'s article clearly demonstrates that as pitchers get older they do not adhere to these counts, which increases the risk of injury.