Humeral cortical and trabecular changes in the throwing athlete: a quantitative computed tomography study of male college baseball players.
OBJECTIVE
To examine bone adaptation to the mechanical loading of baseball using quantitative computed tomography.


METHODS
Quantitative computed tomography was performed on both throwing and nonthrowing humeri of 8 male college baseball players. Quantitative computed tomography geometric variables and volumetric cortical density were measured at each of 5 sites, located at 15%, 25%, 35%, 50%, and 75% of humeral length from distal to proximal. Volumetric trabecular density was measured at the most distal site only.


RESULTS
Significant side-to-side differences in favor of the throwing arm were found at all sites for total cross-sectional bone area (8%-17%, P < 0.01), cortical bone area (17%-29%, P < 0.01), and cortical bone thickness (18%-31%, P < 0.05). There were no important differences seen for cortical density; in contrast, trabecular density was significantly different in favor of the throwing arm at the one site measured (38%, P < 0.05).


CONCLUSIONS
The dominant humerus of baseball players adapts via increases in cortical size and trabecular density.
New York University School of Medicine, and Department of Radiology, New York University/Hospital for Joint Diseases, New York, NY, USA. jmn267@med.nyu.edu
Jeffry M
JM
Neil
Mark E
ME
Schweitzer
D000222:Adaptation, Physiological / Q000502:physiology; D000293:Adolescent; D000328:Adult; D001484:Baseball; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging*; D008297:Male; D014057:Tomography, X-Ray Computed