Abstract
Purpose
To analyze the current literature regarding risk factors associated with medial ulnar
collateral ligament (MUCL) injury in baseball players and to serve as a robust source
for identifying modifiable risk factors that once optimized, have the potential to
reduce injury risk.
Methods
Comprehensive search of the available literature was performed according to the Preferred
Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Studies
were included if they evaluated risk factors for MUCL injuries in the elbow of baseball
players. Risk of bias assessment was performed via Methodological Index for Non-randomized
Studies (MINORS) scoring system. The Oxford Centre for Evidence-Based Medicine was
used to determine level of evidence. Variables of interest; player age, position,
shoulder motion, humeral retrotorsion, joint laxity, strength, balance, geography,
velocity, pitch count, pitch types, throwing volumes, and throwing mechanics were
recorded.
Results
Twenty-one studies were included in this systematic review. MINORS scores ranged from
75-87% and variables demonstrated significant heterogeneity. Performance-based risk
factors for MUCL injury included: increased pitch count (both annual and per game),
higher percentage of fastballs thrown, smaller pitch repertoire, and/or a loss of
pitching velocity. Biomechanical studies demonstrated the relationship between decreased
shoulder range of motion (total ROM, ER, IR, and Abduction), increased humeral retrotorsion,
increased elbow valgus opening in the throwing arm, lower Y-Balance score, and increased
lateral release position to increased MUCL injury.
Conclusion
Risk factors for MUCL injury can generally be categorized into 4 primary groups: 1)
various player demographics and characteristics, (2) throwing too hard (high velocity),
(3) throwing too much (pitch count/volume), and (4) throwing with poor mechanics.
In this systematic review, the most significant non-modifiable risk factors for MUCL
injuries included: increased glenohumeral retrotorsion and elbow valgus opening. The
most consistent modifiable risk factors included: total shoulder range of motion,
pitch count, pitch selection, Y balance score, and lateral release position. Pitch
velocity was inconsistent in literature, but most studies found this as a risk for
injury. These risk factors may serve as appropriate targets for future evidence-based
injury mitigation strategies.
Level of Evidence
Level IV (Systematic review of level II-IV studies)
Key Terms
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Article info
Publication history
Accepted:
December 30,
2022
Received in revised form:
December 14,
2022
Received:
May 24,
2022
Publication stage
In Press Journal Pre-ProofFootnotes
Joshua R. Labott: [email protected] (publishable)
Devin P Leland: [email protected] (publishable)
Sara E. Till: [email protected]
Adam Diamond: [email protected]
Christian Hintz: [email protected]
Joshua S. Dines: [email protected]com
Acknowledgements:
The authors would like to acknowledge the support from the Foderaro-Quattrone Musculoskeletal-Orthopaedic Surgery Research Innovation Fund.
Identification
Copyright
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