Influence of repetitive batting on capitellar subchondral bone density distribution

Osteochondritis dissecans of the capitellum occurs in adolescent baseball players, with repetitive throwing recognized as a major risk factor. Whether repetitive batting contributes to cumulative capitellar loading remains unclear. We hypothesized that repetitive batting would increase cumulative mechanical loading on the humeral capitellum, as assessed with computed tomography (CT) osteoabsorptiometry.

In this cross-sectional study, 32 healthy male collegiate baseball players (64 elbows), all right-handed throwers, underwent bilateral elbow CT during the off-season. Based on batting handedness and throwing side, elbows were categorized into 4 groups (throwing and batting group [T&B]; contralateral; throwing group [T]; batting group [B]). Capitellar subchondral bone density was analyzed with CT osteoabsorptiometry. Mean Hounsfield unit (HU) values and percentage of high-density area (%HDA, top one-third of HU values) were compared between groups.

Throwing elbows showed higher mean HU and %HDA than nonthrowing elbows. The T&B group had greater values than the contralateral group (mean HU, 935 ± 153 vs. 913 ± 88.9, P = .046; %HDA, 32.6 ± 14.8 vs. 25.0 ± 15.5, P = .049). Similarly, the T group had greater values than the B group (mean HU, 962 ± 101 vs. 884 ± 142, P = .044; %HDA, 31.8 ± 14.5 vs. 26.4 ± 12.5, P = .042). Batting handedness was not associated with side-specific difference (T&B vs. T and contralateral vs. B).

Throwing exposure was associated with greater capitellar subchondral bone density, whereas no clear batting-related side-specific difference was detected in collegiate players.