The Development of Humeral Retrotorsion and Its Relationship to Throwing Sports

The Role of Humeral Torsion on Glenohumeral Rotation in Injured Baseball Players

Background

Differences in rotational range of motion (ROM) compared to humeral retrotorsion (HRT)-corrected rotational ROM exist in healthy baseball athletes, but it is unclear whether these differences exist in a pathological population.

Purpose/Hypothesis

The purpose of this study was to determine if there are disparities between objectively measured differences in ROM and HRT-corrected deficits in injured baseball players. It was hypothesized that disparities would exist between (1) the side-to-side difference in glenohumeral external rotation (GER) and the HRT-corrected glenohumeral external rotation deficit (GERD) and (2) the side-to-side difference in glenohumeral internal rotation (GIR) and the HRT-corrected glenohumeral internal rotation deficit (GIRD).

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Data from 172 baseball players with shoulder or elbow injuries (45 shoulder, 127 elbow) were reviewed in July 2023. GER and GIR were measured on the injured and noninjured sides of all players, and diagnostic ultrasound was used to measure HRT. Dependent t tests were run to compare the side-to side differences in GER and GIR with the HRT-corrected GERD and GIRD, respectively.

Results

In the players with a shoulder injury, there was a significant disparity between the side-to-side difference in GER and the HRT-corrected GERD (2°± 14° vs -13°± 15°, respectively) and between the side-to-side difference in GIR and the HRT-corrected GIRD (-14°± 8° vs 2°± 9°, respectively) (P < .001 for both). Similarly, players with an elbow injury had significant disparities between the side-to-side difference in GER and the HRT-corrected GERD (6°± 9° vs -10°± 9°, respectively) and between the side-to-side difference in GIR and the HRT-corrected GIRD (-12°± 8° vs 4°± 10°, respectively) (P < .001 for both).

Conclusion

The results supported our hypothesis that there were disparities between objectively measured differences in GER and GIR compared with the HRT-corrected GERD and GIRD in injured baseball players. Consideration must be given to osseous adaptations that occur at the glenohumeral joint when evaluating and treating this population.

A narrative review of little league shoulder: proximal humeral physis widening is only one piece of the puzzle, it is time to consider posterior glenoid dysplasia

Baseball athletes across all levels of play are at an increased risk for upper extremity injury due to the supraphysiologic demands on the shoulder and elbow during overhead throwing. Little league baseball players present with a unique subset of injuries that can affect the growth plate, commonly at the shoulder or the elbow. Ascertaining a diagnosis and plan of care for little league shoulder (LLS) historically focuses on the proximal humeral physis in skeletally immature throwing athletes presenting with shoulder pain. However, while not a current standard of care, posterior glenoid dysplasia is often present in youth baseball athletes presenting with LLS, warranting a shift in the way clinicians evaluate for and treat the youth baseball athlete's pathologic shoulder. Therefore, purpose of this narrative review is 2-fold: first, to describe the current standard of care as it relates to a diagnosis of LLS, and second, to critically describe a comprehensive evaluation process for youth throwing athletes with shoulder pain that includes screening for evidence of posterior glenoid dysplasia. This paper summarizes the current state of the available evidence for anatomic considerations of LLS in the baseball athletes throwing shoulder. Additionally, we provide a framework for clinical evaluation using a multidisciplinary approach to evaluate the entire kinetic chain of the youth baseball athlete presenting with LLS and posterior glenoid dysplasia. A case study is presented to describe common presentations, clinical and objective examinations, and a plan of care from time of evaluation to return to throwing.

Humeral Torsion in Relation to Shoulder Range of Motion in Elite Field Hockey Players

CONTEXT

Sport-specific adaptations in shoulder rotation range of motion (ROM) and the relationship with humeral torsion have been described in overhead-throwing sports. However, information is lacking for other shoulder-loading sports such as field hockey. Therefore, this study's purpose was to evaluate humeral torsion in elite, male field hockey players and explore its association with shoulder ROM.

DESIGN

Cross-sectional study.

METHODS

Twenty-five male, elite field hockey players were included. Humeral torsion and shoulder external and internal rotation ROM were evaluated bilaterally by ultrasound and an inclinometer smartphone application, respectively.

RESULTS

Field hockey players showed a significantly increased humeral retroversion on the dominant compared with the nondominant side (P < .001; Cohen d = 1.75), along with a significantly increased external (P = .004; Cohen d = -0.64) and decreased internal rotation ROM (P = .003; Cohen d = 0.65). This finding illustrates a shift in total shoulder rotational ROM arc. Correlation analysis showed a significant moderate association between the increased humeral retroversion and decreased internal rotation ROM on the dominant side (r = .523).

CONCLUSIONS

Elite male field hockey athletes show sport-specific adaptations regarding humeral torsion and shoulder rotation ROM, similar to throwing athletes. These findings increase our insight into the field hockey athlete's shoulder, which is essential to optimize performance and assist in correctly interpreting shoulder rotational ROM measurements.

A Field-expedient Arm Care Screening Tool Can Identify Musculoskeletal Risk Factors in Baseball Players

BACKGROUND

Preseason movement screening can identify modifiable risk factors, deterioration of function, and potential for injury in baseball players. Limited resources and time prevent high school baseball coaches from performing movement screens on their players.

HYPOTHESIS

The arm care screen (ACS) will be highly sensitive to detecting musculoskeletal risk factors.

STUDY DESIGN

Cross-sectional.

LEVEL OF EVIDENCE

Level 3.

METHODS

A total of 150 baseball players were independently scored on the ACS electronically by reviewing a video recording of each player's screening performance. Discriminability of the ACS was determined with a 2 × 2 contingency table dichotomizing musculoskeletal risk factors as present or absent based on a predetermined cutoff value and those who passed or failed the corresponding ACS subtest.

RESULTS

High sensitivity was observed on the reciprocal shoulder mobility (0.89; 95% CI 0.81-0.94), 90/90 total body rotation (0.86; 95% CI 0.79-0.92), and lower body diagonal reach (0.85; 95% CI 0.78-0.91) tests of the ACS suggesting sufficient ability to identify musculoskeletal impairments and risk factors.

CONCLUSION

The ACS is a simplistic screening tool that the coach can administer to discriminate between youth, high school, and college-level baseball players who possess musculoskeletal risk factors. The ACS subtests demonstrated high sensitivity for correctly identifying musculoskeletal risk factors common in baseball players and can be useful as a screening tool for baseball coaches developing arm care exercise programs.

CLINICAL RELEVANCE

A field-expedient screen could provide coaches the ability to identify musculoskeletal risk factors that need to be addressed to minimize injury risk factors in a time-efficient manner.

Glenohumeral Internal Rotation Deficit in the Adolescent Overhead Athlete: A Systematic Review and Meta-Analysis

OBJECTIVE

The objective of this review was to investigate the average glenohumeral internal rotation deficit (GIRD) in the dominant arm of adolescent overhead athletes and to examine the association with shoulder and elbow injuries.

DESIGN

Systematic review and meta-analysis.

SETTING

MEDLINE, Embase, and PubMed were searched from inception to August 1, 2020.

PARTICIPANTS

Adolescent overhead athletes with glenohumeral range of motion (ROM) measurements.

INTERVENTIONS

Nonoperative treatments of GIRD.

MAIN OUTCOME MEASURES

Glenohumeral ROM measurements comparing the dominant and nondominant extremities were pooled in a meta-analysis.

RESULTS

Twenty-five studies were included in this review, which involved 2522 overhead athletes. Pooled internal rotation (IR) deficit of the dominant arm was 9.60° (95% confidence interval [CI] 7.87°-11.32°, P < 0.00001), with an external rotation (ER) gain of 6.78° (95% CI 4.97°-8.59°, P < 0.00001) and a total ROM (TROM) deficit of 1.78° (95% CI -0.70° to 4.26°, P = 0.16). The association between GIRD and shoulder or elbow injury was not clearly defined. Two studies reported treatment, and both used nonoperative treatment in the form of physiotherapy and sleeper stretches.

CONCLUSIONS

The adolescent overhead athlete has roughly 10° of IR deficit in their dominant arm, accompanied by nearly 7° of ER gain, with similar ROM measurements for injured and uninjured athletes. Those with pathological GIRD have a greater degree of IR deficit, but without an accompanying compensatory increase in ER, leading to a TROM deficit of nearly 15°. Surgical treatment in the absence of other indications is rare, whereas physiotherapy and sleeper stretches remain the first-line treatment.

Bilateral glenohumeral internal rotation deficit (GIRD) in elite gymnasts

INTRODUCTION

The "Glenohumeral Internal Rotation Deficit (GIRD)" is known as the difference in internal rotation range of motion (IRRM) between the dominant and non-dominant shoulder of overhead athletes as a result of asymmetric loading. As in contrast loading pattern in gymnastics are quite symmetric and structural changes often occur bilaterally, the question arises if GIRD might develop bilaterally in gymnasts as one source of common bilateral shoulder pathologies and to search for underlying structural adaptations.

MATERIALS AND METHODS

A group of 35 elite gymnasts (8-24 years) were recruited from a local Olympic Training Centre and compared to a paired cohort of 28 non-overhead athletes. Clinical examinations, digital range of motion (ROM)-measurement, ultrasonographic humeral torsion measurement, and standardized MRI scans of both shoulders were obtained and examined for structural pathologies, cross-sectional areas (CSA) of the rotator cuff muscles and capsular thickness.

RESULTS

ROM-measurements showed significant decrease in IRRM in the gymnasts groups by age, with IRRM of 48.6° (SD: 8.4°, CI 95%: 43.0-54.3°) at age group 1 (8-10 years) and IRRM of 10° (SD: 11.4°; CI 95%: 0-22.0°) at age group 4 (18-26 years), that was statistically significant for the entire cohort (p = 0.017) compared to the controls. CSA were not significantly different between the cohorts, while there was a slightly increased humeral retrotorsion in the gymnasts as well as a statistically significant posterior capsular thickening.

CONCLUSION

A new bilateral form of GIRD was identified in higher age groups of youth and senior elite gymnasts enrolled in this study. Despite to former definition of GIRD there was no compensatory increase in external rotation range of motion (ERRM) but an association with posterior capsular thickening, while there was no periscapular muscle hypertrophy. Humeral retrotorsion was also slightly increased in the gymnasts group.

Differences in Glenohumeral Range of Motion and Humeral Torsion Between Right-Handed and Left-Handed Professional Baseball Pitchers

BACKGROUND

Elite pitchers have demonstrated significant differences in glenohumeral range of motion and humeral torsion compared with the nonthrowing population. Furthermore, abnormal shoulder range of motion measurements have been associated with different injury risks and challenges in assessing rehabilitation progress. Variations in range of motion and torsion due to handedness in the asymptomatic professional population have yet to be investigated in the literature.

HYPOTHESIS

No significant differences in glenohumeral range of motion and humeral torsion would exist between asymptomatic right- and left-handed professional pitchers.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

217 Major League Baseball pitchers from a single organization were evaluated over a 7-year period between 2013 and 2020. Range of motion was measured with a standard goniometer. Ultrasound scanning was used to determine neutral position of the shoulder, and the degree of humeral torsion was measured with a goniometer.

RESULTS

Right-handed pitchers demonstrated significantly greater values of glenohumeral external rotation (118.5° vs 112.7°; P < .001) in their throwing arms compared with their left-handed counterparts. Right-handed pitchers also showed greater values of glenohumeral internal rotation deficit (13.9° vs 4.8°; P < .001) and side-to-side differences in humeral retrotorsion (-23.1° vs -2.2°; P < .001). Left-handed pitchers demonstrated significantly greater flexion deficits in the throwing arm compared with their right-handed counterparts (7.5° vs 0.0°; P < .001).

CONCLUSION

In the throwing arm, right-handed pitchers demonstrated significantly greater measures of external rotation, glenohumeral internal rotation deficit, and humeral retrotorsion compared with left-handed counterparts. Furthermore, right-handed pitchers demonstrated a significant side-to-side difference in retrotorsion, whereas left-handed pitchers did not. However, left-handed pitchers demonstrated a side-to-side shoulder flexion deficit that was not present in the cohort of right-handed pitchers. The correlation between humeral retrotorsion and increased external rotation indicates that osseous adaptations may play a role in range of motion differences associated with handedness. Additionally, these findings may explain observed differences in several throwing metrics between right- and left-handed pitchers. Knowledge of these differences can inform rehabilitation programs and shoulder maintenance regimens.

Residual Effects of Glenohumeral Range of Motion, Strength, and Humeral Retroversion on Prior Overhead Athletes After Cessation of Sport

Background:

Research has shown that repetitive stress from playing an overhead (OH) sport can cause musculoskeletal and osseous adaptations to occur on the dominant side. Additionally, there are limited data about the residual effects of these adaptations after the cessation of sports participation.

Purpose:

To investigate the effects of prior participation in an OH sport versus not participating in an OH sport on glenohumeral range of motion (ROM), isometric strength, and humeral retroversion (HR).

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

Forty-eight college-aged individuals participated. Participants were split into 2 groups: (1) individuals who previously participated in an OH sport (n = 20; age, 20.3 ± 1.1 years; height, 166.3 ± 15.27 cm; weight, 72.2 ± 13.5 kg) and (2) individuals who previously did not play an OH sport (n = 28; age, 20.6 ± 0.9 years; height, 168.8 ± 6.3 cm; weight, 68.1 ± 15.1 kg). After completing a health history questionnaire, the following were measured: side-to-side shoulder internal rotation (IR) and external rotation (ER) ROM via an inclinometer, isometric shoulder strength via a handheld dynamometer, and HR using an ultrasound imaging machine. A Mann-Whitney U test was used to determine group differences, and a Wilcoxon t test was used to analyze side-to-side differences within each group.

Results:

The Mann-Whitney U test revealed a statistically significant group difference for dominant shoulder ER ROM (U = 162.00, P = .014). Specifically, the prior OH group had significantly more ER than the control group. Within the prior OH group, testing revealed that athletes had significantly more HR (Z =–2.782, P = .005), ER ROM (Z =–1.979, P = .048), and ER isometric strength (Z =–2.763, P = .006) on their dominant than nondominant shoulder and significantly less IR ROM (Z =–3.099, P = .002) on their dominant than nondominant shoulder.

Conclusion:

Prior OH sports participation may have residual osseous and musculoskeletal effects that remain after cessation of the sport.

Chronic Effects of Pitching on Muscle Thickness and Strength of the Scapular Stabilizers in Professional Baseball Players

BACKGROUND

The posterior scapular muscles eccentrically contract to disperse the high forces observed in the deceleration phase of pitching. Muscular adaptations often occur following chronic eccentric loading, however, no study has evaluated the adaptations of the posterior scapular muscles with regard to throwing and their relationship with humeral retroversion (HR) in professional pitchers.

HYPOTHESIS

Significant chronic adaptations in muscle thickness (MT) and strength of the trapezius and rhomboids would be observed in healthy professional baseball pitchers, and there would be a significant relationship between humeral adaptations (ie, HR) and posterior scapular muscle adaptations (ie, strength and MT).

STUDY DESIGN

Cross-sectional; Level 3.

METHODS

A total of 28 healthy male professional baseball pitchers (age, 22 ± 2 years; mass, 95 ± 17 kg; height, 190 ± 7 cm) were included in the study. Bilateral isometric muscle strength of the upper trapezius (UT), middle trapezius, lower trapezius (LT), and rhomboids was measured during a maximum voluntary isometric contraction. Diagnostic ultrasound images of the UT, middle trapezius, LT, rhomboid major, and rhomboid minor muscles were collected bilaterally to measure MT. HR was also quantified bilaterally with ultrasound. Paired sample t tests were used to compare dominant and nondominant strength and MT. Pearson correlation coefficients were used to assess the relationship between HR, isometric strength, and MT.

RESULTS

A significantly increased MT of the LT was found on the dominant arm compared with the nondominant arm (5.4 ± 1.1 mm vs 4.4 ± 1.5 mm; P = 0.00). The Pearson correlation coefficient demonstrated a significant weak negative relationship between HR and rhomboid major MT (P = 0.03; R = -0.36), and a significant weak negative correlation between HR and middle trapezius isometric strength (P = 0.03; R = -0.37).

CONCLUSION

LT thickness was greater in the throwing arm compared with the nonthrowing arm of pitchers, suggesting a positive adaptation of the LT. Interestingly, there was a weak negative relationship between HR and both rhomboid major MT and middle trapezius isometric strength. This negative relationship suggests that since increased HR leads to decreased internal rotation range of motion during deceleration, the scapula may be forced into anterior tilt and protraction, which can place excessive eccentric load on the rhomboid major and middle trapezius.

The Effects of Physical Activity on Physeal and Skeletal Development

»

There is increasing evidence in the literature regarding the important health impact of and risk factors for injury in youth sport.

»

Increasing pediatric and adolescent activity intensity, such as is seen in earlier single-sport focus and specialization, may be associated with morphological changes in the growing skeleton.

»

Chronic subacute injury to the developing physes in the active child can lead to stress on the growth plate and surrounding tissues that induces developmental morphological changes in the joint.

»

There is evidence to suggest that frequent participation in sports that place particular stress across the physes of the proximal humerus, the proximal femur, and the distal radius can be associated with an increased risk of inducing developmental and morphological changes that could lead to future joint dysfunction and premature degeneration.

»

Additional research is necessary to better define the pathoetiology of activity-mediated morphological changes, as well as to create and validate parameters for safe involvement in competitive physical activities.

Junior and Collegiate Tennis Players Display Similar Bilateral Asymmetries of Humeral Retroversion

CONTEXT

Overhead throwing athletes consistently display significant bilateral differences in humeral retroversion (HRV). However, there is limited evidence regarding HRV asymmetries in tennis players despite similarities between the overhead throw and tennis serve.

OBJECTIVE

To determine if junior and collegiate tennis players demonstrate bilateral differences in HRV, and whether the magnitude of the side-to-side difference (HRVΔ) was similar across different age groups.

DESIGN

Cross-Sectional Study Setting: Field-Based Patients or Other Participants: Thirty-nine healthy tennis players were stratified into three age groups: Younger Juniors (n = 11; age = 14.5 ± 0.5 years), Older Juniors (n = 12; age = 17.1 ± 0.9 years), and Collegiate (n = 16; age = 19.6 ± 1.2 years).

MAIN OUTCOME MEASURES

Three-trial means were calculated for HRV for the dominant and nondominant limbs, and HRVΔ was calculated by subtracting the mean of the nondominant side from the dominant side. Paired-sample t-tests were utilized to determine bilateral differences in HRV, while a one-way ANOVA was used to compare HRVΔ between groups.

RESULTS

For all three groups, HRV was significantly greater in the dominant arm compared to the nondominant arm (Younger Juniors: dominant = 62.8° ± 9.1° vs nondominant = 56.3° ± 6.8°, P = .039; Older Juniors: dominant = 75.5° ± 11.2° vs nondominant = 68.6° ± 14.2°, P = .043; Collegiate: dominant = 71.7° ± 8.5° vs nondominant = 61.2° ± 6.9°, P = .001). However, no significant differences were detected in HRVΔ when compared across age groups (P = .511).

CONCLUSIONS

Consistent with studies involving overhead throwing athletes, tennis players demonstrated significantly greater measures of HRV in the dominant limb. Further, the development of HRV asymmetries appear to have occurred prior to the teenage years as no changes were observed in HRVΔ between age groups.

Does Youth Baseball Result in Morphologic Changes of the Lateral Elbow? A Prospective MRI Study

BACKGROUND

Stress from overhead throwing results in morphologic changes to the shoulder in youth baseball players. With greater valgus torque stresses, the elbow experiences injuries specifically attributed to throwing. However, no previous work that we know of has assessed throwing-related morphologic changes of the elbow without associated conditions.

QUESTIONS/PURPOSES

(1) Do children who play competitive baseball have enlargement or overgrowth of their radial head shape and/or capitellum compared with the nondominant elbow on MRI? (2) Do children who stop playing year-round baseball have less enlargement of the lateral elbow structures than children who maintain a high level of play?

METHODS

A prospective study was conducted between 2015 and 2018 on preadolescent boys who underwent voluntary MRI of their bilateral elbows before the start of the spring baseball season. Twenty-six children agreed to participate out of a four-team league that was asked to participate; their first MRI was obtained at a mean (range) age of 12 years (10 to 13). We also obtained their history related to throwing and performed a physical examination. Players had a mean of 5.6 years of playing before their first MRI, and half the children (13 of 26) were year-round baseball players. Sixty-two percent (16 of 26) reported being either or both a pitcher or catcher as their primary position. No child was excluded from participation. Three years later, these boys were asked to return for repeat MRI and physical examinations. Fifty-eight percent (15 of 26) of players were still playing at the 3-year MRI. Continued play or new onset of pain was documented. Radiographic measurements were then compared between dominant and nondominant arms, and the differences of these changes were compared between those who had continued playing during the study period and those who had quit. The measurements were made in all three planes of the radial head and capitellum, both osseous and cartilaginous. Measurement intrarater and interrater reliability were in the good-to-excellent range (intraclass correlation coefficient 0.77 to 0.98).

RESULTS

When we compared dominant and nondominant arms, we found there was no dominant arm overgrowth (difference between baseline and 3-year measurements) in any measurement; for example, sagittal capitellum measurements in dominant arms were 2.5 ± 1.1 mm versus non-dominant arms: 2.8 ± 1.1 mm (mean difference -0.23 [95% CI -0.55 to 0.08]; p = 0.13). There was only undergrowth of the cartilaginous axial diameter of the radial head (change in dominant: 2.5 ± 1.3 mm; change in nondominant: 3.2 ± 1.7 mm; mean difference -0.64 mm [95% CI -1.2 to -0.06]; p = 0.03). There was no enlargement of the lateral elbow structures when children who continued to play were compared with children who stopped playing; for example, the difference in the bone-only growth ratio of the sagittal radial head to humerus of those still playing was 0.001 ± 0.03 and it was 0.01 ± 0.03 for those not playing (mean difference -0.01 [95% CI -0.04 to 0.01]; p = 0.29).

CONCLUSION

In healthy children who play baseball for multiple years between the ages of 6 to 11 years, continued torque at the elbow from throwing does not result in morphologic changes as it does in the shoulder. Despite evidence that injuries and surgery because of long-term participation in a throwing sport results in a larger radial head and capitellum, our study presents evidence that outside an injured elbow, throwing alone does not appear to change the morphology of the lateral elbow. Therefore, changes to the radial head size could presuppose other elbow pathology and future study could be performed to better evaluate the correlation.

LEVEL OF EVIDENCE

Level I, prognostic study.

ASSESSMENT OF HUMERAL TORSION BY PALPATION IN BASEBALL PITCHERS: A VALIDATION STUDY

Background/Purpose

Greater humeral retroversion has been associated with shoulder and elbow injuries. Methods for measuring torsion include radiography, computed tomography (CT) and sonography (US) which may be costly or unavailable. A palpation method might be a reliable alternative to imaging techniques. The purpose of the current study was to examine the construct validity of the palpation technique for humeral torsion by (1) determining if a side-to-side difference in humeral torsion (HT) could be detected in a cohort of baseball pitchers using the palpation technique and (2) compare the side-to-side difference in HT obtained through the palpation method to the US method.

Hypothesis

Clinical assessment of HT by palpation is reliable and is as accurate as sonographic HT measurements among overhead athletes.

Methods

Twenty collegiate and high school pitchers were assessed. Bilateral shoulder passive external rotation (ER) and internal rotation (IR) range of motion were measured. Humeral torsion was indirectly measured using sonographic and palpatory methods. Paired t-tests were used to determine HT side-to-side difference measured by US versus palpation. Pearson's correlation coefficient (r) was used to determine the relationship between HT side-to-side difference detected by palpation and US, and relationships among IR and ER of the shoulder and HT side to-side difference measurements.

Results

There was significantly greater HT in dominant versus nondominant arm assessed by both palpation (5°±5, p=0.0004) and ultrasound (9°±11, p=0.0007). There was a positive correlation between both methods of HT measurement (r = 0.522, p=0.018). Palpation significantly underestimated HT as compared to US measurements (difference 4°±9, p=0.048). Difference in IR between shoulders correlated with HT measured by palpation (r=-0.651, p=0.002) and US (r=0.569, p=0.009). Increased ER in the dominant versus nondominant arm correlated with the side-to-side difference in HT measured by both palpation (r = 0.509, p=0.02) and US (r = 0.602, p=0.005).

Conclusion

Greater HT on the dominant versus nondominant shoulder via palpation indicated this method can be used to assess HT in pitchers. HT assessed by palpation correlated with HT assessed by US. However, the magnitude of side-to-side difference in HT was smaller with palpation compared to US, and the two techniques should not be used interchangeably. Nevertheless, assessment of HT via palpation is a reliable and practical method and its use should be encouraged.

Level of Evidence

Level 3, measurement study.

Does humeral torsion play a role in shoulder and elbow injury profiles of overhead athletes: a systematic review

BACKGROUND

Humeral retrotorsion (HRT) is one bony adaptation that occurs in overhead athletes. This bony adaptation often leads to bilateral changes in range of motion at the glenohumeral joint. Because HRT can create different stress environments on the surrounding tissue, it may play a role in upper-limb injury and pain profiles. Therefore, the aim of this review was to examine whether HRT plays a role in shoulder and elbow injury profiles.

METHODS

Two separate critical appraisal tools were administered: the Newcastle-Ottawa Scale (case control) and the Appraisal Tool for Cross-sectional Studies. The primary author extracted all data and obtained means and standard deviations for each outcome. Cohen d effect sizes (ESs) were calculated (ES [95% confidence interval]) for all HRT measurements including nondominant, dominant, and side-to-side differences. Finally, the Strength of Recommendation Taxonomy was used to evaluate the overall strength of the recommendation.

RESULTS

Nine articles were included in this review. Large ESs were present in 2 studies on examination of symptomatic and asymptomatic dominant HRT and ranged between 0.83 (0.08-1.55) and -2.57 (-3.66 to 1.99). The majority of all ESs for all HRT measurements were moderate or low, rendering comparisons between asymptomatic and symptomatic cohorts that were not clinically meaningful.

CONCLUSION

The Strength of Recommendation Taxonomy rating was C based on inconsistent findings. Differences in sports populations and definitions of injuries across studies may be one reason for the varying ESs. HRT does occur in the overhead population, but the degree to which this HRT starts to affect upper-limb injury is unknown and is more than likely player specific and multifactorial.

THE EFFECT OF HUMERAL RETROTORSION ON PITCH VELOCITY IN YOUTH BASEBALL PLAYERS

BACKGROUND

Pitching velocity is a critical measure of performance, but it may also play a role in the development of injury. It has been proposed that increased humeral retrotorsion (HRT) may be an advantageous adaptation among throwers, resulting in increased throwing velocity. However, there is limited published data directly investigating this relationship.

PURPOSE / HYPOTHESIS

The purpose of this study was to examine the effects of HRT on pitching velocity in a group of youth baseball players. We hypothesized that there would be a positive association between pitching velocity and increased humeral retrotorsion.

STUDY DESIGN

Cross-sectional cohort study.

METHODS

Demographic and physical variables that may correlate to pitching velocity (age, height, weight, glenohumeral external rotation (ER) range of motion, dominant arm humeral retrotorsion and shoulder internal rotation (IR) strength) were assessed. Univariate analysis using Pearson correlation coefficients examined the relationship of each variable to pitching velocity. Significant variables were retained and entered into a multivariable regression analysis.

RESULTS

All variables significantly correlated with pitching velocity (p<0.05) with the exception of ER (r = -0.169,p = 0.145). Multivariable regression model was significant and accounted for 81.7% of pitching velocity (R² = 0.817 F(5,70) = 62.59,p<0.001). Player age (B = 1.7,p < 0.001), height (B = 0.225,p = 0.001) and shoulder IR strength (B = 0.622, p < 0.001) significantly contributed to the model. After accounting for all other variables, HRT had a non-significant (B = 0.005,p = 0.884) and very small contribution to pitching velocity adding only .005mph per degree of HRT.

CONCLUSIONS

Pitching velocity in youth baseball players is strongly influenced by age, height and IR strength. In opposition to the hypothesis, the degree of humeral retrotorsion did not have a significant effect on pitching velocity.

LEVEL OF EVIDENCE

Level 3.

The challenge of the sporting shoulder: From injury prevention through sport-specific rehabilitation toward return to play

Shoulder injuries and sports-related shoulder pain are substantial burdens for athletes performing a shoulder loading sport. The burden of shoulder problems in the athletic population highlights the need for prevention strategies, effective rehabilitation programs, and a individually based return-to-play (RTP) decision. The purpose of this clinical commentary is to discuss each of these 3 challenges in the sporting shoulder, to assist the professional in: (1) preventing injury; (2) providing evidence-based practice rehabilitation and; (3) to guide the athlete toward RTP. The challenges for injury prevention may be found in the search for (the interaction between) relevant risk factors, develop valid screening tests, and implement feasible injury prevention programmes with maximal adherence from the athletes. Combined analytical and functional testing seems mandatory screening an athlete's performance. Many questions arise when rehabilitating the overhead athlete, from exercise selection, over the value of stretching, toward kinetic chain implementation and progression to high performance training. Evidence-based practice should be driven by the available research, clinical expertise and the patient's expectations. Deciding when to return to sport after a shoulder injury is complex and multifactorial. The main concern in the RTP decision is to minimize the risk of re-injury. In the absence of a "gold standard", clinicians may rely on general guidelines, based on expert opinion, regarding cutoff values for normal range of motion, strength and function, with attention to risk tolerance and load management.

The Relationship Between Humeral Torsion and Arm Injury in Baseball Players: A Systematic Review and Meta-analysis

CONTEXT

Humeral torsion (HT) has been linked to various injuries and benefits. However, the exact interplay between HT, shoulder range of motion (ROM), competition level differences, and injury risk is unclear.

OBJECTIVE

To determine the relationship between HT, ROM, and injury risk in baseball players. Secondarily, to determine HT based on competition level.

DATA SOURCES

PubMed, Embase, Web of Science, CINAHL, and Cochrane databases were searched from inception until November 4, 2018.

STUDY SELECTION

Inclusion criteria consisted of (1) HT measurements and (2) arm injury or shoulder ROM.

STUDY DESIGN

Systematic review.

LEVEL OF EVIDENCE

Level 3.

DATA EXTRACTION

Two reviewers recorded patient demographics, competition level, HT, shoulder ROM, and injury data.

RESULTS

A total of 32 studies were included. There was no difference between baseball players with shoulder and elbow injuries and noninjured players (side-to-side HT difference: mean difference [MD], 1.75 [95% CI, -1.83 to 2.18]; dominant arm: MD, 0.17 [95% CI, -1.83 to 2.18]). Meta-regression determined that for every 1° increase in shoulder internal rotation (IR), there was a subsequent increase of 0.65° in HT (95% CI, 0.28 to 1.02). HT did not explain external rotation (ER ROM: 0.19 [95% CI, -0.24 to 0.61]) or horizontal adduction (HA ROM: 0.18 [95% CI, -0.46 to 0.82]). There were no differences between HT at the high school, college, or professional levels.

CONCLUSION

No relationship was found between HT and injury risk. However, HT explained 65% of IR ROM but did not explain ER ROM or HA ROM. There were no differences in HT pertaining to competition level. The majority of IR may be nonmodifiable. Treatment to restore and maintain clinical IR may be important, especially in players with naturally greater torsion. HT adaptation may occur prior to high school, which can assist in decisions regarding adolescent baseball participation.

The throwing shoulder in youth elite handball: soft-tissue adaptations but not humeral retrotorsion differ between the two sexes

PURPOSE

In youth handball players, knowledge about the development of soft-tissue adaptation and humeral retrotorsion is limited. The purpose of this study was to investigate differences in adaptations in the glenohumeral rotational range of motion and humeral retrotorsion of the throwing arm between male and female youth elite handball players.

METHODS

One-hundred and thirty-eight youth elite handball players (mean age: 14.1 ± 0.7 years) were assessed for glenohumeral external (ER) and internal (IR) rotational ranges of motion and humeral retrotorsion (HRT) by means of a manual goniometer and a portable ultrasound device. Sports-specific adaptations between the dominant and non-dominant shoulders and between male and female adolescents were calculated.

RESULTS

Handball players showed side-to-side differences in IR and ER in the throwing shoulder. HRT did not correlate with the measurements of rotational ROM of the throwing arm. Male athletes showed a more pronounced glenohumeral internal rotation deficit than female athletes (13.1° ± 22.8° vs. 5.1° ± 14.0°, p = 0.014). Adaptations in HRT but no sex differences could be seen in the throwing shoulder (16.5° ± 9.6°) compared to the non-throwing shoulder (13.5° ± 9.4°, p < 0.001).

CONCLUSION

Loss of internal rotation and gain in external rotation in youth handball players seem to be more related to adaptive changes in the soft-tissues than to HRT. Male athletes showed stronger throwing-related adaptations in the rotational range of motion but not in humeral torsion in their dominant shoulder than female athletes.

LEVEL OF EVIDENCE

Cross-sectional study, Level II.

Shoulder Range of Motion and Baseball Arm Injuries: A Systematic Review and Meta-Analysis

OBJECTIVE

Arm injuries in baseball players are a common problem. The identification of modifiable risk factors, including range of motion (ROM), is essential for injury prevention. The purpose of this review was to assess the methodologic quality and level of evidence in the literature and to investigate the relationship between shoulder ROM and the risk of arm injuries in baseball players.

DATA SOURCES

Relevant studies in PubMed, CINAHL, Embase, and SPORTDiscus published from inception to August 1, 2017.

STUDY SELECTION

Only studies that encompassed healthy baseball cohorts who were assessed for shoulder ROM and prospectively evaluated for injuries throughout a baseball season or seasons were included.

DATA EXTRACTION

Six articles met the search criteria. Only 3 studies were included in the meta-analysis due to disparate participant groups.

DATA SYNTHESIS

The modified Downs and Black scale (0-15 points) was used to analyze methodologic quality. Study quality ranged from 11 to 14. Four studies received high-quality (≥12) and 2 studies received moderate-quality (≥10) scores. The overall pooled analysis demonstrated that absolute and internal-rotation deficits (-5.93 [95% confidence interval {CI} = -9.43, -2.43], P < .001 and 4.28 [0.71, 7.86], P = .02, respectively) and absolute total ROM (TROM; -6.19 [95% CI = -10.28, -2.10]; P = .003) were predictors of injury, and these data exhibited homogeneity (absolute IR P value = .77, I² = 0%; IR deficit P value = .41, I² = 0%; absolute TROM P value = .78, I² = 0%). No significance was observed for absolute external rotation (-2.86 [95% CI = -6.56, 0.83], P = .13), which had data with high heterogeneity ( P = .003; I² = 83%). A deficit in horizontal adduction was a predictor of injury (-8.32 [95% CI = -12.08, -4.56]; P < .001); these data were homogeneous but yielded a moderate heterogenic effect ( P = .16; I² = 50%).

CONCLUSIONS

High-quality evidence demonstrated that deficits in throwing-arm TROM and IR were associated with upper extremity injury in baseball players. Heterogeneity across studies for horizontal adduction suggested that this may be a modifiable risk factor for injury, but it requires further research.

Changes in humeral retrotorsion and the development of little league shoulder: A case study

OBJECTIVE

To present the case of a 15 year-old baseball player with Little League Shoulder (LLS) and describe how developmental changes in the angle of humeral retrotorsion (HRT) may contribute to the underlying pathology of this condition.

DESIGN

Case report.

SETTING

Two years earlier, the patient had participated in a healthy player screening program at which time measurements of height, weight, shoulder motion, and HRT were obtained. These same measures were obtained during the initial evaluation after injury. Between measurements, the patient grew more than 12 cm in height and demonstrated a large shift in proximal humeral torsional alignment with a change of 13° and 19° of HRT in the dominant and non-dominant sides respectively.

PARTICIPANT

15 year-old male (1.88 m, 79.8 kg), right hand dominant baseball pitcher and 3rd baseman diagnosed with right LLS.

CONCLUSION

The pathoanatomical factors contributing to LLS are not well understood. The degree of HRT is a developmental characteristic that changes over the course of physiological maturation. The large changes in HRT seen in this case, may implicate rapid changes in HRT angle create a window of increased susceptibility to physeal damage, and contribute to the development of LLS.

Rotational evaluation of humeral shaft fractures with proximal extension fixed using the MIPO technique

INTRODUCTION

Diaphyseal fractures with proximal humeral extension can be treated using a helical model, so it is lateral on the proximal aspect and on the diaphyseal segment in the anterior surface.

OBJECTIVE

Our objective was to evaluate possible rotational deviations using minimally invasive plate osteosynthesis (MIPO) and to determine how it affects upper limb function.

METHODS

We followed 11 patients for a period of two years. The proximal approach was anterior-lateral, and the distal approach was anterior, dividing the brachial muscle. For rotational evaluation, we used the semi-axial incidence described by Oztuna et al., assessing the degree of retroversion of the humeral head in relation to the elbow. During follow-up, we measured bilateral range of motion, shoulder function (UCLA), and upper limb function (DASH).

RESULTS

For patients whose final result was an increase in retroversion, there was an average difference of 9°, with an increase in the final difference of external rotation of 3° compared with the other shoulder, and no difference between the final levels of internal rotation. In the patients whose final result was a decrease in retroversion, where the distal fragment was fixed in internal rotation, the difference observed was an average of 6°. These patients had an average decrease of the external rotation of 5° with an increase of the internal rotation by two levels. The final functional scores were "good" and "excellent" in all patients, with a mean UCLA of 31.8 points (28-34) and a mean DASH of 9.11 points (0.83-22.2).

CONCLUSION

In all patients, there was a difference in the humeral head retroversion compared to the contralateral limb, but with little clinical repercussion and good or excellent functional scores.

Quantifying humeral retrotorsion in young swimmers and association with swim volume

OBJECTIVES

To compare the humeral retrotorsion (HRT) among non-athletes, amateur swimmers and competitive swimmers and to analyze the relationship between HRT and swim volume in competitive swimmers.

DESIGN

Cross-sectional.

SETTING

Laboratory.

PARTICIPANTS

Ninety children and adolescents, both genders (30 non-athletes: 11.50 ± 1.94 years; 30 amateur swimmers: 11.56 ± 1.81 years; and 30 competitive swimmers: 12.63 ± 2.02 years).

MAIN OUTCOME MEASURES

HRT measurement through the bicipital forearm angle (BFA), by palpation, using an inclinometer to obtain the angle.

RESULTS

Competitive swimmers showed lower BFA (higher HRT) compared to the amateurs (mean difference: 8.3°; p = 0.013; effect size: 0.82) and to the non-athletes (mean difference: 8.5°; p = 0.010; effect size: 0.80). A significant fair negative relationship (r = -0.37; p = 0.04) was found between BFA and volume of swim.

CONCLUSION

Competitive young swimmers present increased HRT and a higher volume of swim is associated with a lower BFA (higher HRT) in these athletes. These results can help to improve the understanding of osseous adaptations in young swimmers.

Physical and Functional Differences in Youth Baseball Players With and Without Throwing-Related Pain

Background:

Identifying risk factors that contribute to shoulder and elbow pain within youth baseball players is important for improving injury prevention and rehabilitation strategies.

Hypothesis:

Differences will exist between youth baseball players with and without a history of upper extremity pain on measures related to growth, shoulder performance, and baseball exposure.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 84 youth baseball players were divided into 2 groups based on self-reported history of throwing-related arm pain. Group differences for growth-related, shoulder performance, and baseball exposure variables were analyzed by use of parametric and nonparametric tests, as appropriate. Multivariate logistic regression was used to assess variables most predictive of pain.

Results:

The group of athletes with pain (n = 16) were taller and heavier, played more baseball per year, and had greater pitching velocity. Athletes with pain also had greater loss of internal rotation range of motion and greater side-to-side asymmetry in humeral retrotorsion (HRT), attributable to lower degrees of HRT within the nondominant humerus. Multivariate analysis revealed that player height was most predictive of pain, with a 1-inch increase in height resulting in a 77% increased risk of pain.

Conclusion:

Vertical growth that accompanies adolescence increases the risk of experiencing throwing-related pain in youth baseball players. Players who are taller, particularly those with faster pitching velocities, are at the greatest risk for developing pain and should be more carefully monitored for resultant injury. The degree of nondominant HRT may have a relationship to the development of pain, but further research is required to better understand the implications of this observation.

Baseball Players With an Ulnar Collateral Ligament Tear Display Increased Nondominant Arm Humeral Torsion Compared With Healthy Baseball Players

BACKGROUND

Previous work has suggested that an increase in the amount of developmentally acquired, dominant arm humeral retrotorsion (D HRT) in the thrower's shoulder may be a potentially protective mechanism. Although the relationship between HRT and shoulder injuries has been reported, the relationship between HRT and ulnar collateral ligament (UCL) tears in baseball players is not known.

PURPOSE

To determine whether D HRT and nondominant arm HRT (ND HRT) measurements in baseball players with a UCL tear differ statistically from a matched healthy cohort.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

D HRT and ND HRT were measured in 112 male competitive high school and collegiate baseball players seen over an 18-month period from 2013 to 2015. A total of 56 participants with a clinical and magnetic resonance imaging-confirmed diagnosis of a throwing-arm UCL tear (UCLInj group) were compared with 56 healthy baseball players with no history of an elbow injury who were matched for age, experience, and position (NUCLInj group). The mean ages in the UCLInj and NUCLInj groups were 17.9 ± 2.2 and 17.6 ± 2.8 years, respectively. Using a previously validated ultrasound method, D HRT and ND HRT were measured in the supine position, and the HRT side-to-side difference (D HRT - ND HRT) was calculated. A 1-way multivariate analysis of variance was used to determine the mean statistical differences between groups ( P < .05).

RESULTS

Baseball players with a UCL tear displayed significantly more humeral torsion (ie, less retrotorsion) in their nondominant arm compared with healthy baseball players (UCLInj = 33.27° ± 10.27°, NUCLInj = 27.82° ± 10.88°; P = .007). Baseball players with a UCL tear did not display any differences in D HRT compared with healthy baseball players (UCLInj = 18.67° ± 9.41°, NUCLInj = 17.09° ± 9.92°; P = .391). Significant side-to-side differences in HRT existed between groups (UCLInj = -14.60° ± 6.72°, NUCLInj = -10.72° ± 6.88°; P = .003).

CONCLUSION

There was a significant increase in mean nondominant arm humeral torsion (ie, less retrotorsion) in the UCL tear group, but there was no significant difference in the mean D HRT between the injured and uninjured groups. A greater HRT side-to-side difference was displayed in the UCL tear group. The extent to which a thrower has developmentally acquired both D HRT and ND HRT may affect elbow UCL tear risk. Furthermore, it is possible that the extent of genetically predisposed ND HRT may influence the throwing-related increase in D HRT.

The Relationship Between Humeral Retrotorsion and Shoulder Range of Motion in Baseball Players With an Ulnar Collateral Ligament Tear

BACKGROUND

Humeral retrotorsion has been investigated in relation to shoulder range of motion (ROM) in healthy baseball players. Currently, there is limited information on the osseous anatomy and development of ulnar collateral ligament (UCL) tears.

PURPOSE

To determine the relationship between humeral retrotorsion and shoulder ROM in baseball players with a UCL tear.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Fifty-four baseball players (mean age, 18.5 ± 2.0 years) with a UCL tear volunteered for this study. Participants were measured bilaterally for shoulder internal (IR) and external rotation (ER) ROM and humeral retrotorsion. Differences between sides (involved to uninvolved) were used to calculate the glenohumeral internal rotation deficit (GIRD), external rotation ROM difference (ERDiff), total rotational motion difference (TRM), and humeral retrotorsion difference (HTDiff). A multivariate regression analysis was performed with GIRD, ERDiff, and TRM regressing on HTDiff. Univariate analysis was performed to further evaluate the effect of the predictors on each outcome separately. To control for the effect of age, weight, duration of symptoms, and years of experience, the variables were included as covariates. An a priori level was set at P < .05.

RESULTS

There was a statistically significant relationship between the GIRD, ERDiff, and TRM results compared with HTDiff (P = .003). Independent analysis revealed a statistically significant relationship between GIRD and HTDiff (P = .004) and between ERDiff and HTDiff (P = .003) but no significant relationship between TRM and HTDiff (P = .999). After adjusting for age, weight, duration of symptoms, years of experience, dominant arm, and position, a significant relationship was found between GIRD and HTDiff (P = .05) and between ERDiff and HTDiff (P = .01). No significant relationship was found between TRM and HTDiff (P = .54). Adjusted univariate regression analysis determined that HTDiff explains approximately 16% of the variance in GIRD (r² = 0.158) and approximately 24% of the variance in ERDiff (r² = 0.237).

CONCLUSION

In baseball players with a UCL tear, approximately 16% of the variance in GIRD and 24% of the variance in ERDiff can be attributed to differences found in humeral retrotorsion between sides. This indicates that humeral retroversion contributes significantly to GIRD and increased ER ROM in baseball players. Recognition of differences in humeral retrotorsion between the dominant and nondominant upper extremities may help explain some but not all of the changes in shoulder ROM commonly seen in baseball players.