Using Ultrasound-guide Corrected Glenohumeral Internal Rotation Deficit as a Risk Factor to Predict Shoulder Injuries in Baseball Players
Using Ultrasound-guide Corrected Glenohumeral Internal Rotation Deficit as a Risk Factor to Predict Shoulder Injuries in Baseball Players
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.
Inclusion criteria:

 1. Age range from 12 to 40 years old.

 2. Playing baseball for at least 1 year.

 3. Still active in training or competition.

 4. The frequency of training or game should be at least 3 times per week, 3 hours per
 time.

 Exclusion criteria:

 1. Subjects with shoulder pain onset due to trauma.

 2. A history of shoulder fractures or dislocation.

 3. Cervical radiculopathy.

 4. Degenerative joint disease of the shoulder.

 5. Surgical interventions on the shoulder.

 6. Inflammatory arthropathy.