Department of Orthopaedic Surgery, Hokkaido University School of Medicine, Kita 15 Nishi 5 Kita-ku Sapporo, Hokkaido 0608368, Japan.
Clin Orthop Relat Res. 2012 Jun;470(6):1534-9. doi: 10.1007/s11999-012-2256-0.
It is important to understand the loading conditions when considering the pathology of shoulder disorders in overhead athletes. However, because throwing is a complicated motion and methods to directly determine stress distribution are complex, direct measurement of the stress distribution across the glenohumeral joint has not been attempted. Subchondral bone density reportedly reflects the cumulative stress acting on a joint surface under actual loading conditions.
QUESTIONS/PURPOSES: To assess alterations in stress distribution across the glenoid cavity caused by pitching, we investigated the distribution of subchondral bone density in nonathletic volunteers and asymptomatic baseball players, including fielders and pitchers.
We collected CT imaging data from the dominant-side shoulder of 10 nonathletic volunteers (controls), 10 fielders, and 10 pitchers in a competitive college baseball league (all men aged 19–24 years, mean 20.7 years). We measured the distribution of subchondral bone density of the glenoid cavity using CT osteoabsorptiometry. The obtained stress distribution map was divided into four segments: anterosuperior, anteroinferior, posteroinferior, and posterosuperior regions. We quantitatively analyzed the location and percentages of high-density regions on the articular surface.
The percentages of high-density regions, including the anteroinferior and posterior segments, were greater in pitchers and fielders than in controls. The percentages of high-density regions did not differ between pitchers and fielders.
The bicentric density patterns indicated that the cumulative force of pitching activity affected the long-term stress distribution across the glenoid cavity.
Our data should be useful for analyzing pitching activity and clarifying the pathology of shoulder disorders associated with throwing.
在考虑上肢运动员肩部疾病的病理学时，了解负荷情况很重要。但是，由于投掷是一种复杂的运动，并且直接确定应力分布的方法很复杂，因此尚未尝试直接测量肩盂关节的应力分布。据报道，软骨下骨密度反映了在实际载荷条件下作用于关节表面的累积应力。
问题/目的：为了评估投球对肩盂关节表面应力分布的改变，我们研究了非运动员志愿者和无症状棒球运动员（包括外野手和投手）的软骨下骨密度分布。
我们从 10 名非运动员志愿者（对照组）、10 名外野手和 10 名参加大学棒球联赛的投手（均为男性，年龄 19-24 岁，平均 20.7 岁）的优势肩采集 CT 成像数据。我们使用 CT 骨吸收仪测量肩盂关节软骨下骨密度的分布。获得的应力分布图分为四个部分：前上、前下、后下和后上区域。我们对关节表面高密度区域的位置和百分比进行了定量分析。
投手和外野手的高密度区域（包括前下和后段）百分比高于对照组。投手和外野手之间高密度区域的百分比没有差异。
双中心密度模式表明，投掷活动的累积力影响了肩盂关节的长期应力分布。
我们的数据对于分析投掷活动和阐明与投掷相关的肩部疾病的病理学应该是有用的。
