Anatomical evaluations of the adipose tissue surrounding the flexor hallucis longus tendon.

This study aimed to evaluate the presence of adipose tissue surrounding the flexor hallucis longus (FHL) tendon through gross dissection and magnetic resonance imaging (MRI). Grossly, we observed the FHL tendon and surrounding tissues in nine cadavers. Using MRI, we quantitatively evaluated each tissue from the horizontal plane in 40 healthy ankles. Macroscopic autopsy revealed the presence of adipose tissue behind the ankle joint between the FHL and fibula, and horizontal cross-sections showed an oval-shaped adipose tissue surrounding the tendon. The cross-sectional area on MRI was 14.4 mm2 (11.7-16.7) for the FHL tendon and 120.5 mm2 (100.3-149.4) for the adipose tissue. Additionally, the volume of the adipose tissue was 963.3 mm3 (896.2-1115.6). There is an adipose tissue around FHL tendon and maybe this close anatomical relationship might influence the function of the tendon and be involved in its pathologies.

Plantar flexion with inversion shows highest elastic modulus of calcaneofibular ligament using ultrasound share wave elastography.

PURPOSE: The functional role of the calcaneofibular ligament (CFL) is still controversial. We aimed to investigate the anatomical features of the CFL on sonography and the elastic modulus of the CFL in different ankle positions using ultrasound shear-wave elastography (SWE). METHODS: In 14 cadaveric ankles, the angle of the CFL with respect to the long axis of the fibula was measured in the following ankle positions: neutral (N), 30° plantar flexion (PF), and 20° dorsiflexion (DF). In addition, in 24 ankles of healthy adult volunteers, the elastic modulus of the CFL was evaluated with ultrasound SWE in the following ankle positions: neutral (N), 30° plantar flexion with inversion (PI), 30° plantar flexion with eversion (PE), 20° dorsiflexion with inversion (DI), and 20° dorsiflexion with eversion (DE). RESULTS: The mean angle of the CFL in N, PF, and DF positions was 139.9° ± 12.7°, 121.3° ± 14.1°, and 158.6° ± 13.1°, respectively. The angle of the CFL in N was significantly greater than that in PF and smaller than that in DF (P < 0.0001, both). The mean elastic modulus of the CFL in the N, PI, PE, DI, and DE positions was: 63.6 ± 50.8, 148.0 ± 39.4, 75.8 ± 40.6, 88.1 ± 31.6, and 61.7 ± 29.4 kPa, respectively. The elastic modulus in PI was significantly higher than in other positions, while the values obtained in DI and DE were also significantly different (P < 0.001, both). CONCLUSIONS: The angle of the CFL increased with DF. Moreover, ultrasound SWE showed that the CFL was tensed and likely to be injured in the PI position.

Elasticity of the Scalene Muscles in Collegiate Baseball Pitchers Using Shear Wave Elastography.

Background: Thoracic outlet syndrome is more common in overhead athletes. The anterior and middle scalene muscles have been associated with thoracic outlet syndrome; however, the relationship between the elastic moduli of the scalene muscles and the overhead-throwing position has not been evaluated. Purpose: To investigate the elastic moduli of the anterior and middle scalene muscles in simulated throwing positions using shear wave elastography. Study Design: Descriptive laboratory study. Methods: We enrolled collegiate baseball players who underwent preseason medical checkups in January and February 2020. The anterior and middle scalene muscles were visualized in the short-axis view using ultrasound. In this view, the elastic moduli of the anterior and middle scalene muscles were measured using shear wave elastography in the following arm and neck positions: (1) adduction and neutral rotation of the shoulder (neutral), (2) 90° of abduction and external rotation of the shoulder (ABER), and (3) ABER with neck rotation toward the nonthrowing side (ABER+NR). Repeated-measures analysis of variance and a paired t test were used to compare the elastic modulus values among the 3 positions and between the 2 muscles, respectively. Results: Overall, 30 baseball players were included. In both scalene muscles, the elastic moduli were significantly greater in the ABER versus neutral position (anterior scalene: 14.4 ± 3.8 vs 9.4 ± 2.0 kPa, respectively [P < .001]; middle scalene: 15.8 ± 5.0 vs 10.9 ± 3.4 kPa, respectively [P < .001]). In the neutral position, the elastic modulus was significantly greater in the middle scalene than the anterior scalene (10.9 ± 3.4 vs 9.4 ± 2.0 kPa, respectively; P = .03). In the ABER+NR position, the elastic modulus was significantly greater in the anterior scalene than the middle scalene (18.1 ± 4.6 vs 15.8 ± 2.6 kPa, respectively; P = .03). Conclusion: Because the ABER position was a simulation of the throwing position, these results indicate that this position could be associated with high elastic moduli of the scalene muscles, and both the anterior and middle scalene muscles may be involved.

Bilateral suprascapular notches are asymmetrically shaped in a third of the Asian population.

PURPOSE: The side-to-side differences within an individual's suprascapular notch (SSN) and the clinical characteristics of an ossified superior transverse scapular ligament are unclear. Therefore, the morphological asymmetry of the SSN was investigated, and the factors associated with the ossification of the superior transverse scapular ligament were analyzed. METHODS: Two hundred and seventy-six computed tomography images were retrospectively analyzed, which included those of both scapulae of Asian patients (mean age, 62.1 ± 19.1 years; males, 197) with high-energy injuries or respiratory diseases. Variations in the SSN were classified into six types based on Rengachary's classification using reconstructed three-dimensional computed tomography. The group with a type VI SSN (completely ossified superior transverse scapular ligament) in at least one scapula was compared with the other group for age, sex, and chronic comorbidities. RESULTS: Among 276 patients, 95 (34.4%) had asymmetric SSNs and 15 (5.4%) had type VI SSNs. There were no significant differences in age, sex, or comorbidities between both the groups. However, on comparing age groups, the prevalence of type VI SSN was higher in patients aged > 70 years than in those aged < 70 years. Fifteen patients had type VI SSNs, which were unilateral in 10 patients. CONCLUSION: Asymmetric SSNs were observed in a third of the Asian patients. There were variations in SSNs between individuals and also within an individual. In the cases with suprascapular nerve paralysis, the difference in SSN morphology compared to a healthy side should be considered. LEVEL OF EVIDENCE: III.

Ulnar Collateral Ligament Reconstruction With the Modified Jobe Technique in Baseball Pitchers.

BACKGROUND: Tearing and insufficiency of the ulnar collateral ligament (UCL) of the elbow result in valgus instability, which can lead to pain while throwing and decline in performance in overhead athletes. PURPOSE: To assess the clinical results of a modified UCL reconstruction technique using 1 bone hole in the ulna and 1 bone tunnel in the humerus in baseball players. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The inclusion criteria were medial elbow pain preventing effective playing, clinically medial elbow laxity, and magnetic resonance imaging results consistent with UCL injury. Patients who were engaged in other sports and in other positions in baseball except pitchers were excluded from this study. Our modified Tommy John procedure was performed via a muscle-splitting approach and an original single-bone-tunnel technique, using a suture anchor. After a minimum of 24 months, patients were evaluated using the Conway scale and the Timmerman-Andrews score. RESULTS: Of 31 patients, 20 baseball pitchers (20 male: 5 high school, 5 collegiate, 8 nonprofessional, and 2 professional pitchers) were reviewed. The mean patient age at the time of operation was 21.9 years, and the mean postoperative follow-up period was 35.1 months (range, 24-66 months). The mean Timmerman-Andrews subjective score improved significantly from pre- to postoperatively (from 68.3 to 98.3; P < .05); the objective score also improved significantly (from 81.1 to 96.4; P = .01). No complications were detected at the latest follow-up. Overall, 19 patients were able to return to their preinjury level of sports or higher. CONCLUSION: UCL reconstruction with 1 bone hole in the ulna and 1 bone tunnel in the humerus demonstrated satisfactory results in baseball pitchers. Our modified technique was safe and achieved satisfactory clinical results, with a 95% rate of return to sports.

Characteristics of Femoral Torsion Angles and Relationships Between Femoral Torsion Angles and Hip Rotational Motion Variables in Adult Baseball Players.

BACKGROUND: Abnormalities in hip rotational motion (HRM) are risk factors for throwing injuries. To evaluate hip rotational motion, it is necessary to assess the torsion angle. However, no studies have investigated the femoral torsion angle (FTA) in baseball players. PURPOSE: To investigate differences in hip FTA of adult baseball players through use of ultrasonography to evaluate the relationship between the FTA and HRM. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 149 elite male baseball players (mean age, 20.0 ± 1.8 years; 64 pitchers, 85 position players) were enrolled in this study. Ultrasonographic assessment of FTA was performed based on the tilting angles of the anterior surface of the femoral neck and condylar axis. The hip internal rotation (HIR) and hip external rotation (HER) were assessed at 0° and 90° of flexion. Data related to FTA and HRM were compared between hips and between pitchers and position players. RESULTS: No significant difference was observed in the FTAs between hips for any player (lead hip, 20.5° ± 9.2°; trail hip, 19.6° ± 9.8°; P = .276). No significant difference was observed in FTAs of both hips between pitchers and position players (lead hip, 20.1° ± 9.4° and 20.9° ± 9.0°, respectively, P = .957; trail hip, 19.5° ± 9.8° and 19.7° ± 9.8°, P = .999). In terms of HER in 90° of hip flexion in both hips, significant differences were observed in HRM variables between pitchers and position players (lead hip, 33.0° ± 8.9° and 37.5° ± 9.8°, respectively, P = .024; trail hip, 35.6° ± 9.6° and 40.4° ± 10.2°, P = .035). Linear regression analysis revealed a significant agreement between the FTA and HIR at both 0° (R = 0.298, P < .001) and 90° of hip flexion (R = 0.279, P < .001). CONCLUSION: Our findings indicated that FTAs were not different between the hips of elite baseball players. Abnormalities of the HRM are not caused by differences in the FTA but rather involve soft tissue tightness around the hip area or other bony morphologic factors in the hip joint.

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

BACKGROUND: Repetitive pitching in childhood was thought to restrict the physiological derotation process of the humeral head. Some studies reported that the side-to-side differences of humeral retroversion in baseball players occurred between the age of 9 and 11 years. The present study investigated the relationship between bilateral humeral retroversion angle and starting baseball age in skeletally mature baseball players. METHODS: One hundred and seventeen male baseball players, who belonged to a college or amateur team, were investigated. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique as described by previous studies. All players were divided into four groups: players who had started playing baseball before the age of 6 years, between 7 and 8 years, between 9 and 10 years and after 11 years. Bilateral humeral retroversion angle was compared among the four starting age groups. RESULTS: All players started playing baseball between 5 and 12 years. Comparing the throwing arm, humeral retroversion in starting age group 11-12 (72°) was significantly smaller than the other 3 groups (81°, 82°, and 80° for groups 5-6, 7-8, and 9-10, respectively). Comparing the non-throwing arm revealed no significant differences among the 4 starting age groups (71°, 72°, 70°, and 66° for groups 5-6, 7-8, 9-10, and 11-12, respectively). CONCLUSIONS: Skeletally mature baseball players who started playing baseball after 11 years had significantly smaller humeral retroversion in the throwing arm than those who started baseball before 11 years.

The differences of humeral torsion angle and the glenohumeral rotation angles between young right-handed and left-handed pitchers.

BACKGROUND: The differences between young right-handed and left-handed baseball players are not well known. This study compared the range of the shoulder motion and humeral torsion angle (HTA) between right-handed and left-handed young baseball pitchers. METHODS: A total of 65 young baseball pitchers (age, 9-12 years; 46 right-handed throwers, R group; and 19 left-handed throwers, L group) were analyzed. The glenohumeral internal rotation (IR) angle and external rotation (ER) angle were measured at 90° shoulder abduction, and HTA was assessed using indirect ultrasonographic techniques. The side-to-side difference in HTA (d-HTA), glenohumeral ER difference (GERD), and glenohumeral IR deficit (GIRD) were calculated. The adjusted GIRD and adjusted GERD were defined as the angles obtained by subtracting d-HTA from GIRD and GERD, respectively, to exclude the influence of humeral retrotorsion difference. RESULTS: HTA and ER of the throwing limb were significantly greater than those of the nonthrowing limb in the R group (HTA: 84° vs. 77°; P < .001, ER: 116° vs. 111°; P < .001), but no significant differences were observed in the L group (HTA: 79° vs. 77°, P = .103; ER: 113° vs. 114°, P = .380). Compared with the R group, the L group showed a significantly smaller d-HTA (2° vs. 8°, P < .001) and GERD (5° vs. -2°, P = .004), but no significant difference was observed in adjusted GERD between the groups (-3° vs. -4°, P = .690). CONCLUSION: Compared with the right-handed pitchers, the side-to-side differences of glenohumeral external rotation angle and humeral torsion angle were significantly smaller in the left-handed pitchers at a young age.

Sonographic sequential change of the anteroinferior labrum following arthroscopic Bankart repair: quantitative and qualitative assessment.

OBJECTIVE: Although arthroscopic Bankart repair is widely performed, little is known concerning the healing process of the Bankart lesion. This study aimed to describe the sonographic sequential change of the anteroinferior labrum following arthroscopic Bankart repair, both quantitatively and qualitatively. MATERIALS AND METHODS: Twenty-five subjects who had undergone arthroscopic Bankart repair were investigated using a sonographic diagnostic device equipped with shear-wave elastographic technology. In addition to measuring the elasticity of the anteroinferior labrum, the B-mode echogram of the anteroinferior labrum was classified into three grades based on the relative echogenicity. Assessment was performed in the affected shoulder 1, 2, 3, 4, 5, 6, and 12 months postoperatively and in the contralateral shoulder 1 month postoperatively for the control. RESULTS: The mean elasticity of the anteroinferior labrum in the affected shoulder 1 and 2 months postoperatively was significantly lower than in the contralateral shoulder (p < 0.001 for both). However, no significant difference was found after 3 months postoperatively. B-mode echograms of the anteroinferior labrum in the contralateral shoulder were classified as grade 0 in all subjects (100%), whereas the percentage of grade 0s in the affected shoulder was 0, 4, 96, and 100% at 1, 2, 3, and 4 months postoperatively. CONCLUSION: Both quantitative and qualitative assessment of repaired anteroinferior labrum using ultrasound became comparable with the contralateral shoulder 3-4 months postoperatively. Ultrasound is a useful decision-supporting tool to prescribe postoperative rehabilitation protocol following arthroscopic Bankart repair, although functional recovery should also be evaluated on an individual basis.

Left-handed skeletally mature baseball players have smaller humeral retroversion in the throwing arm than right-handed players.

BACKGROUND: It is known that the humeral retroversion of baseball players is greater in the throwing arm than in the nonthrowing arm. An investigation measuring dry bone specimens also showed that the right humerus had greater retroversion than the left. Considering these facts, it was hypothesized that humeral retroversion would differ between right- and left-handed players. This study aimed to compare the bilateral humeral retroversion between right- and left-handed skeletally mature baseball players. METHODS: We investigated 260 (196 right-handed and 64 left-handed) male baseball players who belonged to a college or amateur team. Bilateral humeral retroversion was assessed using an ultrasound-assisted technique (humeral torsion angle [HTA]) as described by previous studies. Analysis of covariance, adjusted for handedness and baseball position, assessed the effect of throwing arm dominance on HTA. RESULTS: In comparison of the throwing arm, HTA was significantly smaller in left-handed (left humerus) than in right-handed (right humerus) players (77° vs. 81°; P < .001). In comparison of the nonthrowing arm, HTA was significantly greater in left-handed (right humerus) than in right-handed (left humerus) players (73° vs. 69°; P < .001). The mean side-to-side difference of HTA was significantly smaller in left-handed than in right-handed players (3° vs. 12°; P < .001). CONCLUSIONS: Humeral retroversion of left-handed skeletally mature baseball players was significantly smaller in the throwing arm, greater in the nonthrowing arm, and smaller in side-to-side differences than that of right-handed players. These findings may be key to understanding some of the biomechanical differences between right- and left-handed baseball players.