Abstract
Objectives:
Repetitive throwing in youth baseball places athletes at risk for elbow injuries, and ulnar collateral ligament (UCL) subapophyseal avulsions are increasingly recognized (1). Ultrasound may be an effective technique to examine youth baseball elbows (2), particularly among the less-studied healthy population. The study aim was to evaluate asymptomatic elbows in youth baseball players for evidence of medial epicondylar avulsive changes at the origin of the UCL.
Methods:
After IRB approval, youth baseball players under 19 years without physician care in the prior six months were recruited during three club baseball ultrasound screening sessions. 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. Medial epicondyle avulsions, radiocapitellar osteochondral changes, and indirect humeral torsion angles (3) 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). Descriptive statistics and Kruskal-Wallis comparisons were run between avulsive and non-avulsive groups (95% CI).
Results:
A total of 156 arms in 80 male athletes were evaluated (12.4±1.7 years). Athletes played baseball for 6.6±2.7 years with Pedi-FABS scores of 24.0±5.5. Dominant elbows were rated as 93.5±9.5 (out of 100; SANE) and dominant shoulders were rated 91.2±14.4. On the dominant medial epicondyle, 27/78 (34.6%) elbows showed evidence of a sub apophyseal avulsion: eleven active avulsions (14.1%) and sixteen united avulsion fragments (20.5%). No medial epicondyle changes were visible on the non-dominant elbow. One athlete demonstrated capitellar osteochondral changes (subchondral plate flattening) within the dominant arm, and another player demonstrated osteochondral changes in both arms (subchondral plate concavity in dominant, subchondral plate flattening in non-dominant). Those players with medial epicondyle avulsions demonstrated no differences in humeral retrotorsion or elbow pain on exam compared to those without elbow lesions. 11.1% of players who showed evidence of sub apophyseal avulsion reported playing pitcher, 44.4% reported playing infield, 3.7% reported playing outfield and25.9% reported playing pitcher.
Conclusions:
In a cohort of healthy, United States-based youth baseball players, one-third demonstrated an active or united avulsion of the medial epicondyle on their dominant elbow while capitellar osteochondral abnormalities were minimal. Ultrasound injury surveillance may provide a useful tool in youth baseball players to identify subclinical medial epicondyle subapophyseal injuries prompting earlier treatment and injury prevention strategies.