The Contribution of Posterior Capsule Hypertrophy to Soft Tissue Glenohumeral Internal Rotation Deficit in Healthy Pitchers

Background: The relationship between posterior capsule adaptations and soft tissue glenohumeral internal rotation deficit (GIRD) in healthy pitchers remains unclear. Purpose/Hypothesis: This study aimed to identify if posterior capsule thickness (PCT) was associated with soft tissue GIRD in healthy pitchers. We hypothesized that there would be a positive relationship between soft tissue GIRD and PCT in the dominant arm, no relationship between soft tissue GIRD and PCT in the nondominant arm, and a strong positive relationship between soft tissue GIRD and the bilateral difference in PCT (posterior capsule hypertrophy [PCH]). Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 45 healthy collegiate and professional pitchers were included. Glenohumeral internal rotation and external rotation range of motion, humeral retroversion, and PCT were measured bilaterally. PCT was determined for unilateral posterior capsule measurements, and PCH of the throwing shoulder was calculated as the bilateral difference in PCT. Soft tissue GIRD was calculated as the sum of clinical GIRD and the bilateral difference in humeral retroversion. Pearson correlation coefficients were determined to evaluate the relationships between dominant arm PCT, nondominant arm PCT, and PCH and soft tissue GIRD. Results: Pearson correlations showed that both dominant arm PCT ( R = −0.13; P = .378) and nondominant arm PCT ( R = 0.21; P = .165) were not related to soft tissue GIRD. However, Pearson correlations did show that the amount of PCH was moderately related to soft tissue GIRD ( R = 0.40; P = .007). Therefore, as the posterior capsule hypertrophied, soft tissue GIRD moderately increased. Conclusion: Increased PCH was associated with an increase in soft tissue GIRD in healthy pitchers. If PCT measurements are feasible, clinicians should consider performing bilateral ultrasound assessments to isolate posterior capsule adaptations (ie, PCH). This will allow clinicians to identify pitchers with potentially maladaptive structural adaptations and optimize management strategies throughout the season to counteract them.

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

ABSTRACT 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.

Evaluation of glenohumeral range of motion and humeral retroversion at ages after major change and differences in wrestlers

Purpose: This study aimed to present the change in humeral retroversion (HR) angle (HRA) that occurs in childhood and young adulthood and the potential developmental difference that is observed in wrestlers. Methods: HRA of dominant and non-dominant shoulders (DSHRA and NDSHRA, respectively) were measured using ultrasonography in a group of 30 wrestlers who started wrestling before the age of 13 years (Group 1), a group of 30 young adults, aged between 16–20 years, who were not actively engaged in any branch of overhead sports (Group 2) and a group of children aged between 11–13 years and not actively engaged in any branch of overhead sports (Group 3). Range of motion (ROM) degrees of dominant and non-dominant shoulders in all groups were compared within each group and between the groups. Results: DSHRA (mean: 88.73°, 88.93° and 89.40°) values were significantly higher than NDSHRA (mean: 81.13°, 81.83° and 84.37°) values (p < 0.001, p < 0.001 and p < 0,05) in Groups I, II and III, respectively. Internal rotation and total ROM degrees of the dominant shoulder in Group 1 and 3 were higher than those in Group 2. Conclusion: There is no significant change in terms of HRA in people aged between 11–13 and 16–20 years because of natural development or wrestling. DSHRA values are higher than NDSHRA ones. In contrast to the shoulders of throwers, the shoulders of wrestlers are characterized by an increase in internal rotation, described as “Wrestler’s shoulder.” Level of Evidence: Level III.

Humeral Retroversion and Participation Age in Professional Baseball Pitchers by Geographic Region

Context Baseball is played around the world, including in North America and Latin America. The repetitive and stressful act of throwing can lead to adaptations such as increased humeral retroversion (HR) in the throwing arm. This adaptation is often considered beneficial as it allows more glenohumeral external rotation during the cocking phase of pitching without soft tissue stretching. Therefore, it is speculated that throwing should be started at a young age to capitalize on this adaptation. Interestingly, athletes in different geographic regions of the world often begin organized baseball at different ages. However, range of motion (ROM), HR, and the starting age of baseball have never been examined based on geographic region. Objective To determine if ROM, HR, and the starting age of baseball players differed between professional baseball pitchers from North America and Latin America. Design Cross-sectional study. Setting Clinical setting. Patients or Other Participants Thirty professional pitchers (North American = 19, Latin American = 11) with no current injury or surgery in the previous 6 months. Main Outcome Measure(s) Both ROM and HR were measured in the dominant and nondominant shoulder of each participant. The starting age for baseball was self-reported. Results The Latin American group had more dominant-arm HR (8.7°; P = .034), more nondominant-arm external rotation (5.3°; P = .049), and a trend toward more nondominant-arm HR (6.5°; P = .058), yet they started playing baseball at a later age (by 3.7 years; P = .021) compared with the North American group. Conclusions Latin American players had greater HR but started playing baseball at an older age. These findings contradict current thinking that HR would be more pronounced if baseball was started at a younger age. Additional research is required to better understand HR and the genetic, environmental, and nutritional factors that contribute to its development.

Humeral Retroversion and Injury Risk After Proximal Humeral Epiphysiolysis (Little Leaguer’s Shoulder)

Background: The increased humeral retroversion on the dominant side of throwing athletes is thought to result from repetitive throwing motion. Little Leaguer’s shoulder—a rotational stress fracture of the proximal humeral epiphyseal plate—may influence the risk of humeral retroversion and injury of the shoulder or elbow joint. Purpose: To investigate the effect of Little Leaguer’s shoulder on humeral retroversion and the rates of shoulder and elbow injuries. Study Design: Cohort study; Level of evidence, 3. Methods: 10 high school baseball players (average age, 16.6 years; range, 16-18 years) who had experienced Little Leaguer’s shoulder during elementary or junior high school (average age, 12.6 years; range, 11-15 years) were enrolled in the study. As a control group, 22 high school baseball players (average age, 16.9 years; range, 16-18 years) who had never had any shoulder or elbow injury during elementary and junior high school were included. Humeral retroversion on ultrasonographic measurement, shoulder range of motion, and rates of shoulder and elbow injuries were evaluated. Results: Humeral retroversion was significantly greater on the dominant side than on the nondominant side in both players with Little Leaguer’s shoulder (dominant, 104°± 8°; nondominant, 84°± 12°; P < .001) and controls (dominant, 91°± 13°; nondominant, 81°± 10°; P < .001). In the dominant shoulder, humeral retroversion was greater in the Little Leaguer’s shoulder group than in the control group ( P = .008). When the effects of humeral retroversion were excluded, maximal external rotation was significantly less in the dominant shoulder than in the nondominant shoulder in the Little Leaguer’s shoulder group (by 11°± 12°, P = .02), whereas no significant difference was found between dominant (110°± 11°) and nondominant (111°± 13°) shoulders in the control group ( P = .64). The rates of shoulder and elbow pain were significantly higher in the Little Leaguer’s shoulder group (shoulder pain 80%, elbow pain 70%) than in the control group (shoulder pain 9%, P < .001; elbow pain 32%, P = .04). Conclusion: Humeral retroversion was increased in baseball players without any history of shoulder or elbow injury during elementary and junior high school and was further increased in players who had had Little Leaguer’s shoulder. Increased humeral retroversion after Little Leaguer’s shoulder may be a risk factor for future shoulder or elbow injury.

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

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.