Department of Orthopaedic Surgery, Hokkaido University School of Medicine, Sapporo, Japan.
Am J Sports Med. 2011 Feb;39(2):336-41. doi: 10.1177/0363546510383487. Epub 2010 Nov 17.
The distribution pattern of subchondral bone density is considered to highly reflect the stress distribution across a joint under long-term physiologic loading conditions. Therefore, the biomechanical characteristics over the elbow joint surface under long-term loading conditions of baseball pitching can be determined by a measurement of the distribution pattern.
Stress distribution over the elbow joint surface alters with long-term pitching activities.
Cross-sectional study; Level of evidence, 3.
Computed tomography (CT) imaging data from the dominant elbow of 10 nonthrowing athletes, 10 college baseball fielders, and 10 college baseball pitchers were collected for the current analysis. The distribution of subchondral bone density through the distal articular surface of the humerus was measured using a CT osteoabsorptiometry method. The quantitative analysis of the obtained data focused on location and size of the maximum density area at the articular surface.
The maximum density area of subchondral bone across the articular surface of the distal humerus was located in the posterior part of the trochlea in all subjects. This maximum density area was significantly increased in the pitcher group, compared with that in other groups. Additionally, the pitcher group demonstrated a significant distribution of the maximum density area in the anterior part of the capitellum.
The results indicate that actual stress across the elbow is concentrated in the posterior part of the trochlea in humans. Baseball pitching may produce excessive or repetitive stress against not only this part, but also the anterior part of the capitellum. The majority of osteochondritis dissecans lesions affecting the elbow are found in the anterior part of the capitellum in throwing athletes. The results may support an important role of mechanical conditions in the cause of elbow osteochondritis dissecans.
人们认为，软骨下骨密度的分布模式高度反映了关节在长期生理负荷条件下的应力分布。因此，可以通过测量分布模式来确定在长期投球条件下肘关节表面的生物力学特征。
在长期投球活动中，肘关节表面的应力分布会发生变化。
横断面研究；证据水平，3 级。
本研究共纳入 10 名非投掷运动员、10 名大学生棒球外野手和 10 名大学生棒球投手的优势侧肘部的计算机断层扫描（CT）成像数据。使用 CT 骨吸收计量法测量肱骨远端关节面软骨下骨密度的分布。对获得的数据进行定量分析，重点关注关节表面最大密度区的位置和大小。
所有受试者的肱骨远端关节面的最大软骨下骨密度区均位于滑车的后部。与其他组相比，投球组的最大密度区明显增加。此外，投球组在前头状骨部分也表现出明显的最大密度区分布。
结果表明，实际作用于肘部的应力集中在人类滑车的后部。棒球投球不仅可能对这个部位产生过度或重复的应力，而且还可能对前头状骨的前部产生影响。在投掷运动员中，大多数影响肘部的剥脱性骨软骨炎病变发生在前头状骨的前部。这些结果可能支持机械条件在肘部剥脱性骨软骨炎发病机制中的重要作用。
