Background: Glenohumeral internal rotation deficit (GIRD) is believed to be one of the risk factors contributing to shoulder injuries. In addition, athletes with GIRD of greater than 20° appear to be at a greater risk for the shoulder injuries and surgery. Recently, GIRD can be divided in anatomical GIRD and pathological GIRD (pGIRD). The dominant arm of the athletes with pGIRD have not only humeral retrotorsion (HR) but also stiffer posterior capsule. The soft-tissue effect is believed to be the key point in pathological cascade of throwers. Therefore, the previous studies use gross GIRD as a risk factor may be modified by ultrasound-guide corrected GIRD. Objective: There are 4 objectives for the present study: (1) to investigate the Receiver operating characteristic (ROC) curves of the gross GIRD; (2) to investigate the ROC curves of the ultrasound-guide corrected GIRD; (3) to compare the area under curve (AUC) of the two methods; (4) to compare the gross GIRD and the ultrasound-guide corrected GIRD in baseball players. Design: Baseball players who have played baseball for at least 1 year and still active in training or competition will be recruited in this study. Participant characteristics will be collected by the main assessor, including age, gender, height, weight, dominant arm, practice time, years of playing baseball. Performance/function will be assessed via a Kerlan-Jobe Orthopaedic Clinic shoulder and elbow (KJOC) self-report questionnaire. The shoulder rotation ROM, ultrasound examination including ultrasound-corrected GIRD and posterior capsular thickness and posterior shoulder tightness will also be measured. we will follow subjects for a season. Once the injury occurs, deterioration or at the end of the season, we will collect the data again. Main outcome measures: The shoulder rotation ROM, ultrasound examination and posterior shoulder tightness are main outcomes of the study.
Study Type
OBSERVATIONAL
Enrollment
106
National Taiwan University Hospital
Taipei, Taiwan
alteration of ultrasound-guide corrected GIRD
The participants will be told to supine with 90° of shoulder abduction and elbow flexion. The main assessor places the transducer on the subject's anterior shoulder, perpendicular to the long axis of the humerus in the frontal plane. Then, the humerus will be manually rotated by the assessor for the bicipital groove being centered on the ultrasound image. The ultrasound is then positioned, aided by use of a grid on the ultrasound display. Thus, a line connecting the greater and lesser tubercles can be parallel to the horizontal plane. Last, the second assessor places a digital inclinometer on the ulnar side of the forearm to record the forearm inclination angle, defining the amount of humeral retroversion. This measurement will be repeated 3 times bilaterally and the average will be used for data analysis. The equation of ultrasound-guide corrected GIRD will be gross GIRD minus difference of humeral retroversion between dominant and non-dominant arm.
Time frame: through study completion, an average of 1 year
alteration of posterior capsular thickness
The subject will be positioned upright in a chair with the arm at the side and forearm resting on the thigh. The examiner positions a transducer on the posterior shoulder, visualizing the glenoid labrum, humeral head, rotator cuff, and posterior capsule, defined as the tissue immediately lateral to the tip of the labrum between the humeral head and rotator cuff. When the capsule is identified, the image is paused, and the capsule thickness will be measured by built-in caliper. The imaging procedure will be repeated 3 times, and an average thickness will be determined. This measurement will be taken bilaterally for all subjects.
Time frame: through study completion, an average of 1 year
change of shoulder rotation ROM
Subjects will be placed in supine with the shoulder at 90° of abduction and elbow at 90° of flexion. The main assessor stabilizes the scapula then passively rotating the forearm internally or externally until end feel is reached. Another assessor places a digital inclinometer on the dorsal or the ventral side of the forearm to record the data. Each measurement will be performed 3 times both in the dominant and non-dominant arm, and the average data on the dominant and non-dominant sides will be used for analysis. The total rotation ROM will be the sum of the IR and external rotation.
Time frame: through study completion, an average of 1 year
Injury assessment and classification
The process will be modified according to the previous studies. The players will be prospectively tracked for overuse shoulder injuries throughout the season. For the asymptomatic subjects, any complaint of shoulder problems reported by coach, parents or player will be evaluated by a physical therapist to verify the injury. Moreover, less than 70 KJOC score will be recognized as injury. Injury that does not occur during participation or unrelated to baseball will be excluded. For the symptomatic subject, if he feels exacerbation of the symptom, he will be told to report KJOC score again. Once the decreased score is over 30, the subject will be recognized as injury.
Time frame: up to 24 weeks
change of posterior shoulder tightness
To begin the test, the tester grasps the subject's extremity distal to the epicondyles of the elbow in supine position. The humerus will be passively moved into the starting position of 90˚ of flexion (if not possible, maximal flexion position) and 0˚ of adduction with neutral rotation for assessment of posterior shoulder tightness. At this point, the scapula will be palpated at the lateral border and stabilized with the hand. While the scapula is stabilized, the humerus is then passively moved into a cross-chest adduction with neutral rotation. The humerus is moved until the movement cease (firm end-feel), indicating the end of shoulder tissue flexibility. The recorder places the digital inclinometer parallel to the humerus next to the medial epicondyle. The measured angle indicates the amount of flexibility of the posterior shoulder tissues. A greater angle indicates more flexibility of the shoulder tissue.
Time frame: through study completion, an average of 1 year
change of Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow score (KJOC)
The KJOC is the most common questionnaire for overhead athletes which has been conducted in several studies. Recently, Major League Baseball (MLB) organization also adopts this evaluation tool as the standard for the recovery of injuries in MLB players. The questionnaire is commonly used to assess shoulder function and performance. It is valid, reliable in its pilot form, and responsive in the tested population of adult overhead athletes. KJOC questionnaire range from 0 to 100 and the lower score represents limited function.
Time frame: through study completion, an average of 1 year
days in the disable list
The number of days that players cannot participate in the training or game due to injury will be recorded.
Time frame: through study completion, an average of 1 year
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.