Humeral Retrotorsion and Glenohumeral Motion in Youth Baseball Players Compared With Age-Matched Nonthrowing Athletes

Abstract

Background:

Baseball players exhibit a more posteriorly oriented humeral head in their throwing arm. This is termed humeral retrotorsion (HRT) and likely represents a response to the stress of throwing. This adaptation is thought to occur while the athlete is skeletally immature, however currently there is limited research detailing how throwing activity in younger players influences the development of HRT. In addition, it is presently unclear how this changing osseous orientation may influence shoulder motion within young athletes.

Purpose:

To determine the influence of throwing activity and age on the development of side-to-side asymmetry in HRT and shoulder range of motion (ROM).

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Healthy athletes (age range, 8-14 years) were categorized into 2 groups based upon sports participation; throwers (n = 85) and nonthrowers (n = 68). Bilateral measurements of HRT, shoulder external rotation (ER), internal rotation (IR), and total range of motion (TROM) at 90° were performed using diagnostic ultrasound and a digital inclinometer. Side-to-side asymmetry (dominant minus nondominant side) in HRT and in shoulder ER, IR, and TROM were assessed. Statistical analysis was performed with 2-way analysis of variance and Pearson correlation coefficients.

Results:

Throwers demonstrated a larger degree of HRT on the dominant side, resulting in greater asymmetry compared with nonthrowers (8.7° vs 4.8°). Throwers demonstrated a gain of ER (5.1°), a loss of IR (6.0°), and no change in TROM when compared with the nondominant shoulder. Pairwise comparisons identified altered HRT and shoulder ROM in all age groups, including the youngest throwers (age range, 8-10.5 years). A positive correlation existed between HRT and ER ROM that was stronger in nonthrowers (r = 0.63) than in throwers (r = 0.23), while a negative correlation existed with IR that was stronger in throwers (r = −0.40) than in nonthrowers (r = −0.27).

Conclusion:

Throwing activity causes adaptive changes in HRT and shoulder ROM in youth baseball players at an early age. Other factors in addition to HRT influence shoulder motion within this population.

Keywords

baseball humeral retrotorsion shoulder range of motion injury prevention

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References

Bailey

Beattie

Shanley

Seitz

Thigpen

CA.

Current rehabilitation applications for shoulder ultrasound imaging. J Orthop Sports Phys Ther. 2015;45(5):394-405.

Burkhart

Morgan

Kibler

WB.

The disabled throwing shoulder: spectrum of pathology part I: pathoanatomy and biomechanics. Arthroscopy. 2003;19:404-420.

Chant

Litchfield

Griffin

Thain

LM.

Humeral head retroversion in competitive baseball players and its relationship to glenohumeral rotation range of motion. J Orthop Sports Phys Ther. 2007;37:514-520.

Crockett

Gross

Wilk

. Osseous adaptation and range of motion at the glenohumeral joint in professional baseball pitchers. Am J Sports Med. 2002;30:20-26.

Edelson

The development of humeral head retroversion. J Shoulder Elbow Surg. 2000;9:316-318.

Hibberd

Oyama

Myers

JB.

Increase in humeral retrotorsion accounts for age-related increase in glenohumeral internal rotation deficit in youth and adolescent baseball players. Am J Sports Med. 2014;42(4):851-858.

Kibler

Kuhn

Wilk

. The disabled throwing shoulder: spectrum of pathology—10-year update. Arthroscopy. 2013;29:141-161, e126.

Kocher

Waters

Micheli

LJ.

Upper extremity injuries in the paediatric athlete. Sports Med. 2000;30:117-135.

Krahl

VE.

The torsion of the humerus; its localization, cause and duration in man. Am J Anat. 1947;80:275-319.

10.

Meister

Day

Horodyski

Kaminski

Wasik

Tillman

Rotational motion changes in the glenohumeral joint of the adolescent/Little League baseball player. Am J Sports Med. 2005;33:693-698.

11.

Mullaney

McHugh

Johnson

Tyler

TF.

Reliability of shoulder range of motion comparing a goniometer to a digital level. Physiother Theory Pract. 2010;26:327-333.

12.

Myers

Laudner

Pasquale

Bradley

Lephart

SM.

Glenohumeral range of motion deficits and posterior shoulder tightness in throwers with pathologic internal impingement. Am J Sports Med. 2006;34:385-391.

13.

Myers

Oyama

Clarke

JP.

Ultrasonographic assessment of humeral retrotorsion in baseball players: a validation study. Am J Sports Med. 2012;40:1155-1160.

14.

Myers

Oyama

Goerger

Rucinski

Blackburn

Creighton

RA.

Influence of humeral torsion on interpretation of posterior shoulder tightness measures in overhead athletes. Clin J Sport Med. 2009;19:366-371.

15.

Myers

Oyama

Rucinski

Creighton

RA.

Humeral retrotorsion in collegiate baseball pitchers with throwing-related upper extremity injury history. Sports Health. 2011;3:383-389.

16.

Noonan

Shanley

Bailey

. Professional pitchers with glenohumeral internal rotation deficit (GIRD) display greater humeral retrotorsion than pitchers without GIRD. Am J Sports Med. 2015;43(6):1448-1454.

17.

Osbahr

Cannon

Speer

KP.

Retroversion of the humerus in the throwing shoulder of college baseball pitchers. Am J Sports Med. 2002;30:347-353.

18.

Oyama

Hibberd

Myers

JB.

Changes in humeral torsion and shoulder rotation range of motion in high school baseball players over a 1-year period. Clin Biomech. 2013;28:268-272.

19.

Pieper

HG.

Humeral torsion in the throwing arm of handball players. Am J Sports Med. 1998;26:247-253.

20.

Polster

Bullen

Obuchowski

Bryan

Soloff

Schickendantz

MS.

Relationship between humeral torsion and injury in professional baseball pitchers. Am J Sports Med. 2013;41(9):2015-2021.

21.

Reagan

Meister

Horodyski

Werner

Carruthers

Wilk

Humeral retroversion and its relationship to glenohumeral rotation in the shoulder of college baseball players. Am J Sports Med. 2002;30:354-360.

22.

Roach

Lieberman

Gill

4th Palmer

Gill

3rd . The effect of humeral torsion on rotational range of motion in the shoulder and throwing performance. J Anat. 2012;220:293-301.

23.

Sabick

Kim

Torry

Keirns

Hawkins

RJ.

Biomechanics of the shoulder in youth baseball pitchers: implications for the development of proximal humeral epiphysiolysis and humeral retrotorsion. Am J Sports Med. 2005;33:1716-1722.

24.

Shanley

Kissenberth

Thigpen

. Preseason shoulder range of motion screening as a predictor of injury among youth and adolescent baseball pitchers. J Shoulder Elbow Surg. 2015;24:1005-1013.

25.

Shanley

Rauh

Michener

Ellenbecker

Garrison

Thigpen

CA.

Shoulder range of motion measures as risk factors for shoulder and elbow injuries in high school softball and baseball players. Am J Sports Med. 2011;39:1997-2006.

26.

Shanley

Thigpen

Clark

. Changes in passive range of motion and development of glenohumeral internal rotation deficit (GIRD) in the professional pitching shoulder between spring training in two consecutive years. J Shoulder Elbow Surg. 2012;21:1605-1612.

27.

Whiteley

Ginn

Nicholson

Adams

Indirect ultrasound measurement of humeral torsion in adolescent baseball players and non-athletic adults: reliability and significance. J Sci Med Sport. 2006;9:310-318.

28.

Whiteley

Adams

Nicholson

Ginn

KA.

Reduced humeral torsion predicts throwing-related injury in adolescent baseballers. J Sci Med Sport. 2010;13:392-396.

29.

Whiteley

Ginn

Nicholson

Adams

RD.

Sports participation and humeral torsion. J Orthop Sports Phys Ther. 2009;39:256-263.

30.

Wilk

Macrina

Fleisig

. Correlation of glenohumeral internal rotation deficit and total rotational motion to shoulder injuries in professional baseball pitchers. Am J Sports Med. 2011;39:329-335.

31.

Wilk

Reinold

Macrina

. Glenohumeral internal rotation measurements differ depending on stabilization techniques. Sports Health. 2009;1:131-136.

32.

Wyland

Pill

Shanley

. Bony adaptation of the proximal humerus and glenoid correlate within the throwing shoulder of professional baseball pitchers. Am J Sports Med. 2012;40:1858-1862.

33.

Yamamoto

Kobayashi

Tajika

. Relationship between humeral torsion angle and shoulder range of motion among juvenile baseball players. Sports Orthopaedics and Traumatology. 2015;31(3):182-187.

34.

Yamamoto

Itoi

Minagawa

. Why is the humeral retroversion of throwing athletes greater in dominant shoulders than in nondominant shoulders? J Shoulder Elbow Surg. 2006;15:571-575.