Ostrander R, Escamilla RF, Hess R, Witte K, Wilcox L, Andrews JR. Glenohumeral rotation deficits in high school, college, and professional baseball pitchers with and without a medial ulnar collateral ligament injury. J Shoulder Elb Surg. 2019;28(3):423-429. doi:10.1016/j.jse.2018.11.038
Glenohumeral internal rotation loss (GIRLoss) has been defined as a >18° difference between the throwing and non-throwing shoulder. Also, total rotational motion deficit (TRMD) has been defined as a >5° difference. Both terms have been suggested to be predictive of shoulder and/or elbow injuries in baseball players. There are no published studies that have investigated GIRLoss, TRMD, and a glenohumeral external rotation excess (GERGain, defined as excess in ER in throwing arm relative to the nonthrowing arm) in baseball pitchers in relation to ulnar collateral ligament (UCL) injuries.
The primary purpose of this study was to determine whether GIRLoss, GERGain, and TRMD were significantly different between pitchers with and without a UCL injury. Researchers also investigated if there was a significant difference in these measures among high school, college, and professional pitchers.
- 218 male high school, college and professional pitchers: 108 with a UCL injury, 108 matched without a UCL injury.
- Inclusion criteria for the UCL injury group consisted of all players diagnosed with an acute MUCL tear that adversely affected their ability to pitch plus the following:
- Pain along the medial aspect of their elbow
- Clinical examination findings consistent with a UCL tear and UCL insufficiency
- Magnetic resonance imaging findings consistent with a UCL tear
- All players who subsequently underwent UCL reconstruction
- Exclusion criteria for the UCL injury group and the control group:
- Any previous shoulder or elbow surgery
- Any previous shoulder or elbow injuries that prevented pitching over the past 12 months
- Played additional positions other than pitcher
- Retired from baseball
Shoulder rotational ROM was measured by 2 experienced examiners; an orthopedic surgeon and a physical therapist. Research participants in both groups were tested in supine with the shoulder in 90 degrees of abduction and 10 degrees of horizontal adduction. A 2-way analysis of variance was used to assess the shoulder ROM and the 2 independent variables which were group (with and without UCL injury) and pitching level (high school, college, and professional).
- The UCL injured group had a significantly greater GIRLoss (21° ± 14° vs. 13° ± 8°, P < .001)
- The UCL injured group had a significantly greater GERGain (14° ± 9° vs. 10° ± 9°, P = .004)
- The UCL injured group had a significantly greater TRMD (7° ± 13° vs. 3° ± 9°, P = .008).
- No significant differences were observed among the high school, college, and professional pitchers for GIRLoss, GERGain, and TRMD.
- GIRLoss > 18° was found in 56% of the pitchers in the UCL injury group compared with 28% of those in the control group.
- TRMD > 5° was found in 58% of the pitchers in the UCL injury group compared with 50% of those in the control group.
- Large standard deviations were observed, which implies relatively large inter-subject variability.
- Shoulder ROM was measured retrospectively after UCL injury. Therefore, no cause-and-effect relationship can be determined from this research design.
GIRLoss and TRMD were significantly greater in the UCL injured pitchers compared with the control group. A GIRLoss of 21° was found in this sample of pitchers with a UCL injury. The magnitude of GIRLoss found in this study is significantly higher than previous studies which included both pitchers and position players.
Baseball pitchers with both GIRLoss and TRMD are candidates for selected interventions to improve rotational ROM. Interventions might include self-stretches for the posterior shoulder and manual therapy treatments such as soft tissue and PNF techniques. Pitchers who exhibit GIRLoss but no significant TRMD may be indicative of bony adaptations (humeral retroversion) which do not require interventions.
This study also suggests GIRLoss, GERGain, and TRMD measurements are similar among high school, college, and professional pitchers. Therefore, screening for shoulder ROM impairments (GIRLoss and TRMD) can be performed at all levels of play. High school pitchers with deficits identified may be ideal candidates for injury risk reduction programs which can be integrated into their long-term routines. However, this study offers lower-level evidence based on a selected sample of pitchers analyzed retrospectively after their UCL injury. Therefore, further research is needed before offering stronger recommendations related to shoulder rotational ROM deficits.