Relationship between bilateral humeral retroversion angle and starting baseball age in skeletally mature baseball players—existence of watershed age

Background: Humeral retroversion in baseball players is greater in the dominant shoulder than in the nondominant shoulder. However, the site and severity of the humeral rotational deformity remain unclear. Purpose: To evaluate the site of side-to-side differences in humeral retroversion in baseball players and the severity of these changes through 3-dimensional computed tomographic (3D CT) bone models. Study Design: Cross-sectional study; Level of evidence, 3. Methods: From 2008 to 2014, we studied 25 baseball players (12 pitchers, 13 fielders) who underwent surgery for throwing-related injuries (shoulder injury, 15 players; elbow injury, 10 players). The mean age (±SD) at the time of surgery was 20.0 ± 5.9 years. A reconstructed 3D CT model of the entire humerus was divided into 15 segments of equal height (overall mean, 21.4 ± 1.0 mm). The side-to-side difference in humeral retroversion in each segment was calculated by superimposing the model of the dominant side over the mirror-image model of the nondominant side. Results: The overall mean increase in humeral retroversion was 13.0° ± 6.2° on the dominant side. Significant side-to-side differences in retroversion were present throughout the humerus. The largest side-to-side difference in humeral retroversion was seen at the insertions of the internal rotator muscles (2.5° ± 4.3°) and around the proximal physis (2.5° ± 1.4°). At the insertions of shoulder capsule and rotator cuff tendons, the superior half of the humeral head was more retroverted than the inferior half ( P < .0001). The side-to-side difference in humeral retroversion was significantly greater in the pitchers (16.2° ± 5.1°) than in the fielders (10.0° ± 5.7°) ( P = .009), particularly at the proximal physis. Conclusion: Baseball players exhibited significant side-to-side differences in humeral retroversion at multiple sites throughout the humerus, including the proximal humerus near the epiphyseal plate and at the insertions of the internal rotator muscles, the middle of the humeral shaft, and the distal third of the humerus. Therefore, the increased humeral retroversion at multiple sites throughout the humerus needs to be considered when we perform physical examinations, provide treatment, or undertake biomechanical studies for any throwing-related injuries.

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Humeral retroversion and its association with posterior capsule thickness in collegiate baseball players

Journal of Shoulder and Elbow Surgery ◽

10.1016/j.jse.2011.05.028 ◽

2012 ◽

Vol 21 (7) ◽

pp. 910-916 ◽

Cited By ~ 36

Author(s):

Stephen J. Thomas ◽

Charles Buz Swanik ◽

Thomas W. Kaminski ◽

Jill S. Higginson ◽

Kathleen A. Swanik ◽

...

Keyword(s):

Posterior Capsule ◽

Baseball Players ◽

Collegiate Baseball ◽

Capsule Thickness ◽

Humeral Retroversion

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No Side-to-Side Difference in Humeral Retroversion in Baseball Players with Shoulder Disorders Using a True Three-Dimensional Measurement Technique: Validation and Comparison

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967114s00033 ◽

2014 ◽

Vol 2 (7_suppl2) ◽

pp. 2325967114S0003

Author(s):

Masayuki Saka ◽

Hiroki Yamauchi ◽

Toru Yoshioka ◽

Hidetoshi Hamada ◽

Kazuyoshi Gamada

Keyword(s):

Measurement Technique ◽

Three Dimensional ◽

Baseball Players ◽

Dimensional Measurement ◽

Three Dimensional Measurement ◽

Shoulder Disorders ◽

Humeral Retroversion

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Assessment of Humeral Retroversion Angle in Baseball Players: A Chronological Study

The Showa University Journal of Medical Sciences ◽

10.15369/sujms.27.63 ◽

2015 ◽

Vol 27 (2) ◽

pp. 63-69

Author(s):

Daisuke MAKIUCHI ◽

Hiroaki TSUTSUI ◽

Kenichi MIHARA ◽

Kazuhide SUZUKI ◽

Naoya NISHINAKA ◽

...

Keyword(s):

Baseball Players ◽

Humeral Retroversion

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Little Leaguer’s Shoulder Caused Severe Humeral Retroversion: Ultrasonographic Analysis

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967119s00439 ◽

2019 ◽

Vol 7 (7_suppl5) ◽

pp. 2325967119S0043

Author(s):

Teruhisa Mihata ◽

Masashi Neo

Keyword(s):

High School ◽

Junior High ◽

T Test ◽

Control Group ◽

Baseball Players ◽

Little Leaguer’S Shoulder ◽

Humeral Retroversion ◽

And Control ◽

Dominant Side ◽

Throwing Motion

Objectives: The increased humeral retroversion on the dominant side in throwing athletes is thought to result from repetitive throwing motion. In the previous studies, the degree of increased humeral retroversion was various, suggesting that other factors may affect humeral retroversion. Little Leaguer’s shoulder, which is rotational stress fracture of the proximal humeral epiphyseal plate, may change humeral retroversion. The purpose of this study was to investigate effect of Little Leaguer’s shoulder on humeral retroversion. Methods: Ten high-school baseball players (average, 16.6 years; range, 16 to 18 years), who had had Little Leaguer’s shoulder during elementary or junior high schools (average, 12.6 years; range, 11 to 15 years), were enrolled in the study. As a control group, 22 high-school baseball players (average, 16.9 years; range, 16 to 18 years), who have never had shoulder or elbow pain, were included in this study. Humeral retroversion was ultrasonographically measured on the dominant and non-dominant sides. Humeral retroversion was compared between dominant and non-dominant shoulders with paired t-test. Side-to-side difference in humeral retroversion was compared between Little Leaguer’s shoulders and control group with unpaired t-test. Results: Humeral retroversion was significantly greater on the dominant side than on the non-dominant side in both Little Leaguer’s shoulder (Dominant, 104°±8°; Non-dominant, 84°±12°; P < .001) and control groups (Dominant, 91°±13°; Non-dominant, 81°±10°; P < .001). The side-to-side difference in humeral retroversion in Little Leaguer’s shoulder group (20°±10°) was significantly greater than that in control group (10°±10°, P = .02). Conclusion: Humeral retroversion was increased with repetitive throwing motion without any symptom in the shoulder and elbow joint. Additional increase in humeral retroversion was made when the players had had Little Leaguer’s shoulder in elementary or junior high school.

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Relationships Between Humeral Retroversion, Anterior Glenohumeral Laxity, and Forward Scapular Posture in Collegiate Baseball Players

10.30707/etd2014.mukaihara.y ◽

2014 ◽

Author(s):

Yuya Mukaihara

Keyword(s):

Baseball Players ◽

Collegiate Baseball ◽

Humeral Retroversion

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Humeral Retroversion and Its Relationship to Glenohumeral Rotation in the Shoulder of College Baseball Players

The American Journal of Sports Medicine ◽

10.1177/03635465020300030901 ◽

2002 ◽

Vol 30 (3) ◽

pp. 354-360 ◽

Cited By ~ 268

Author(s):

K.M. Reagan ◽

Keith Meister ◽

Mary Beth Horodyski ◽

Dave W. Werner ◽

Cathy Carruthers ◽

...

Keyword(s):

Range Of Motion ◽

Internal Rotation ◽

Soft Tissues ◽

External Rotation ◽

Baseball Players ◽

Bony Anatomy ◽

Humeral Retroversion ◽

College Baseball ◽

The Difference ◽

Mean Differences

Background Previous studies have documented changes in musculature, bony anatomy, and glenohumeral rotation in the dominant shoulder of baseball players. Hypothesis In a group of asymptomatic college baseball players the total range of motion in the dominant and nondominant shoulders will be similar. Any measured increase in external rotation and decrease in internal rotation occurring between the two sides will be consistent and directly correlate with an increased angle of humeral retroversion in the dominant extremity. Study Design Descriptive anatomic study. Methods Fifty-four asymptomatic college baseball players were examined. Standard measurements of glenohumeral range of motion were made and humeral retroversion was determined radiologically. Results Total rotational motion, measured at 90° of glenohumeral abduction, was 159.5° for the dominant shoulders and 157.8° for the nondominant shoulders. Mean differences in external and internal rotation in the dominant versus nondominant extremities were 9.7° and 8.2°, respectively. Humeral retroversion measured 36.6° ± 9.8° in the dominant and 26° ± 9.4° in the nondominant extremity. The mean difference in retroversion correlated significantly by Pearson's product moment with the difference in external (P = 0.001) and internal (P = 0.003) rotation measurements. Conclusions There is a pattern of increased external rotation and decreased internal rotation in the dominant extremity that significantly correlates with an increase in humeral retroversion. The loss of internal rotation and gains in external rotation may be more strongly related to adaptive changes in proximal humeral anatomy than to changes in the soft tissues.

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