Medial Epicondyle Morphology in Elite Overhead Athletes: A Closer Look Using 3-Dimensional Computer Simulation

BACKGROUND: Prior studies have attempted to determine morphological characteristics of the medial epicondyle in overhead athletes, but no study has reported on precise quantitative differences between elite overhead athletes and control patients. HYPOTHESIS: The medial epicondyle in overhead athletes is larger in volume than those of control patients. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Computer simulation modeling from advanced (computed tomography/magnetic resonance imaging) imaging of the elbow of 37 patients (22 elite overhead athletes, 15 control patients) was performed to provide detailed assessment of the morphological characteristics of the medial epicondyle. Several quantitative metrics regarding the medial epicondyle were measured and compared across both cohorts, including that of epicondyle width (medial-lateral), height (superior-inferior), thickness (anterior-posterior), volume, percentage cortical volume, and morphology of the inferior slope of the epicondyle. RESULTS: The medial epicondyle in overhead athletes was significantly larger than that found in nonathlete controls (4976 vs 3682 mm(3); P = .001). There was no significance between the 2 cohorts in medial-lateral width (16.8 vs 16.6 mm; P = .68), but there was a difference in anterior-posterior thickness (16.96 vs 14.40 mm; P = .001) and superior-inferior height (39.55 vs 35.86 mm; P = .09) in athletes versus controls. The epicondyle volume was 97.9% cortical bone in athletes compared with 82.3% in control patients (P < .001). There were no differences in the morphology of the inferior epicondyle slope between the 2 groups. CONCLUSION: The medial epicondyle in overhead athletes is larger in volume and anterior-posterior thickness than those of control patients. Additionally, the medial epicondyle is comprised nearly entirely of cortical bone in overhead athletes. CLINICAL RELEVANCE: These quantitative findings support the theory of adaptive remodeling in skeletally immature overhead athletes.