Background: The correlation between ulnar collateral ligament (UCL) abnormalities detected through magnetic resonance imaging (MRI) and the presence of elbow symptoms in baseball players has been a subject of ongoing investigation.
Purpose: This study aimed to directly compare microscopic MRI findings of the UCL in baseball players experiencing elbow symptoms versus those without symptoms. The central hypothesis was to challenge the direct link, suggesting that the MRI grade of UCL injuries might not directly correspond to medial elbow symptoms in this athletic population.
Study Design: This research employed a cross-sectional study design to evaluate and compare these two groups. It is classified as Level 3 evidence.
Methods: The study included skeletally mature baseball players who underwent detailed high-resolution microscopic MRI scans of their medial elbows as part of routine medical evaluations. Players with prior elbow surgeries or acute traumatic UCL injuries were excluded to focus on non-traumatic, potentially chronic UCL changes. Participants were categorized into two groups: those exhibiting elbow symptoms (symptomatic) and those without (asymptomatic). The appearance of the UCL on microscopic MRI was then graded using a 4-grade scale. Researchers also assessed for additional medial elbow abnormalities, such as bony fragments around the medial epicondyle, osteophytes or fragments at the sublime tubercle, and bone marrow edema (BME) within the sublime tubercle.
Results: The study encompassed 426 baseball players, totaling 426 elbows, with an average age of 20 years (ranging from 14 to 41 years). The asymptomatic group consisted of 158 elbows, while the symptomatic group included 268 elbows. Interestingly, the MRI grading of UCL abnormalities revealed a similar distribution across both groups. In the asymptomatic group, 29% were graded as Grade I, 41% as Grade II, 25% as Grade III, and 5% as Grade IV. Similarly, in the symptomatic group, the distribution was 28% Grade I, 44% Grade II, 23% Grade III, and 5% Grade IV. Statistical analysis showed no significant difference in UCL MRI grades between the symptomatic and asymptomatic baseball players (P = .9). However, a notable difference emerged in the presence of bone marrow edema in the sublime tubercle. BME was significantly more frequent in the symptomatic group compared to the asymptomatic group (P < .001).
Conclusion: This study revealed that there is no significant difference in the MRI grades of the UCL when comparing symptomatic and asymptomatic elbows in baseball players. Notably, approximately 30% of elbows in both groups displayed high-grade UCL injuries on MRI. The presence of bone marrow edema in the sublime tubercle, however, was found to be a more reliable indicator of elbow symptoms than the MRI grade of the UCL itself. This suggests that while UCL abnormalities are common in baseball players, even without symptoms, bone marrow edema in the sublime tubercle may be a more relevant factor in understanding medial elbow pain in this population.
