2025 ISAKOS Congress in Munich, Germany

2025 ISAKOS Biennial Congress Paper


Reduced Ulnohumeral Gapping in Youth Baseball Players with Subapophyseal Medial Epicondyle Avulsions

James McGinley, BS, Dallas, Texas UNITED STATES
Jacob Jones, MD, Dallas, TX UNITED STATES
Cassidy Morgan Schultz, BS, Dallas, TX UNITED STATES
Robert Van Pelt, MPH, Dallas, TX UNITED STATES
Charles W Wyatt, CPNP, Plano, Texas UNITED STATES
Katie Sloma, PT, DPT, CSCS, Dallas, TX UNITED STATES
Sophia Ulman, PhD, Dallas, Texas UNITED STATES
Brandee D. Schmidt, PT, MS, DPT, Frisco, TX UNITED STATES
Monique Prebensen, ATC, Dallas, TX UNITED STATES
Philip Wilson, MD, Dallas, TX UNITED STATES

Texas Scottish Rite, Dallas, TX, UNITED STATES

FDA Status Not Applicable

Summary

Youth baseball players with subapophyseal UCL avulsions demonstrated decreased ulnohumeral gapping compared to youth baseball players without avulsions.

Abstract

Objectives:
While youth baseball players can exhibit ulnar collateral ligament (UCL) injuries (1) similar to adults, they can also suffer subapophyseal medial epicondyle avulsions at the origin of the UCL (2). Studies have demonstrated increased gapping of the ulnohumeral joint in baseball players with UCL injuries through dynamic valgus ultrasound assessment (3,4); however, literature evaluating ulnohumeral gapping in youth baseball players with subapophyseal UCL avulsions is lacking.

Methods

After IRB approval, baseball players under 19 years without physician care in the prior six months were recruited from four baseball-focused community events. Basic demographics and sports participation history were obtained. Patient-reported outcomes included the Single Assessment Numeric Evaluation (SANE), The Hospital for Special Surgery Pediatric Functional Activity Brief Scale (Pedi-FABS), and the American Shoulder and Elbow Surgeons (ASES) score. UCL structure, subapophyseal medial epicondyle avulsion status, radiocapitellar osteochondral changes, and ulnohumeral gapping were assessed via ultrasound exam from one fellowship-trained physician using a 4-20 MHz High Frequency Linear transducer with a GE Venue Go portable ultrasound machine (Venue Go R4, GE HealthCare, Chicago, Illinois, USA).

Results

A total of 78 dominant elbows in 79 youth male baseball athletes were analyzed (12.4  1.7 years). Twenty-seven athletes demonstrated subapophyseal medial epicondyle avulsions (11 active, 16 united). Athletes practiced 8.3  2.4 months per year and had spent 6.6  2.7 years playing baseball. No baseball players demonstrated any UCL substance tears on ultrasound examination. No differences in years of sport played, Pedi-FABS, ASES, SANE, or humeral retrotorsion were observed between the avulsion and non-avulsion groups nor between active and united avulsions. With ultrasound ulnohumeral stress testing of dominant elbows, the avulsion group demonstrated significantly decreased gapping compared to the non-avulsion group (0.43  0.24 mm vs. 0.62  0.30 mm; p=0.016). No difference in gapping was noted between active and united subapophyseal avulsions.

Conclusion

Youth baseball players with subapophyseal UCL avulsions demonstrated decreased ulnohumeral gapping compared to youth baseball players without avulsions. This is contrary to adult baseball players with UCL injuries that show increased ulnohumeral gapping. The reason for this remains unknown and further research is needed on this younger population.

References:

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