Risk Factors of Shoulder and Elbow Injuries in Baseball: A Scoping Review of 3 Types of Evidence

BACKGROUND: Shoulder and elbow overuse injuries are the most common problems in baseball players. No scoping review has compared the findings from different types of evidence. PURPOSE: To map the broad evidence from 3 types of evidence (epidemiological, biomechanical, and narrative) on potential risk factors for shoulder and elbow injuries in baseball and identify gaps in the existing literature to guide future research. STUDY DESIGN: Scoping review. METHODS: Eight electronic databases were searched from inception to May 14, 2020. Any peer-reviewed papers that investigated or discussed potential risk factors for shoulder and elbow injuries in baseball were included. RESULTS: A total of 302 studies (107 epidemiological studies, 85 biomechanical studies, and 110 narrative reviews) were included. Risk factors were categorized into 9 domains: sports profiles, physical characteristics/functions, pitching mechanics, performance, behavioral, psychosocial, biological and developmental, injury/sports profiles, and environmental factors. Studies were consistent in supporting limited shoulder range of motion (ROM) and player positions (pitchers or catchers) as risk factors for shoulder injuries. For elbow injuries, the majority of the included studies suggested that being pitchers or catchers and working with higher ball velocity can be risk factors. CONCLUSION: Findings were consistent in some risk factors, such as limited shoulder ROM and positions. However, findings were inconsistent or limited for most factors, and substantial research gaps were identified. Research assessing those factors with inconsistent or limited evidence in the current literature were recognized to be priorities for future studies.