Yamamoto Nobuyuki, Itoi Eiji, Abe Hidekazu, Kikuchi Kazuma, Seki Nobutoshi, Minagawa Hiroshi, Tuoheti Yilihamu
Biomechanics Laboratory, Division of Orthopedic Research, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
Am J Sports Med. 2009 May;37(5):949-54. doi: 10.1177/0363546508330139. Epub 2009 Mar 4.
There have been few biomechanical studies to clarify which size of a glenoid defect is critical. However, those studies have assumed that the defect occurred anteroinferiorly. Recent studies have reported that the defect is located anteriorly rather than anteroinferiorly. Therefore, the effect of the anterior, not anteroinferior, glenoid defect on shoulder stability needs to be investigated.
The anterior glenoid defect would have a similar effect on anterior shoulder stability as that of the anteroinferior glenoid defect.
Controlled laboratory study.
Eight fresh-frozen cadaveric shoulders were used (mean age, 74 years). The specimen was attached to a shoulder-testing device with the arm in abduction and external rotation. An osseous defect was created stepwise with a 2-mm increment of the defect width. The stability ratio was used to evaluate joint stability. With a 50-N axial force, the translational force applied to the humeral head was measured by a force transducer.
The stability ratio without a defect (32% +/- 6%) significantly decreased after creating a 6-mm defect (17% +/- 5%; P = .0001), which was equivalent to 20% of the glenoid length.
An osseous defect at 3 o'clock with a width that was equal to or greater than 20% of the glenoid length significantly decreased anterior stability.
The results suggest that reconstruction of the glenoid concavity might be necessary in shoulders with an anterior glenoid defect of at least 20% of the glenoid length.
很少有生物力学研究来阐明多大尺寸的肩胛盂缺损至关重要。然而，这些研究假定缺损发生在肩胛盂前下方。近期研究报告称，缺损位于前方而非前下方。因此，需要研究前方而非前下方肩胛盂缺损对肩关节稳定性的影响。
前方肩胛盂缺损对肩关节前向稳定性的影响与前下方肩胛盂缺损相似。
对照实验室研究。
使用8个新鲜冷冻的尸体肩关节（平均年龄74岁）。将标本连接到肩部测试装置上，手臂处于外展和外旋位。以缺损宽度每次增加2毫米的方式逐步制造骨缺损。使用稳定性比率评估关节稳定性。施加50牛的轴向力，通过力传感器测量施加于肱骨头的平移力。
无缺损时的稳定性比率（32%±6%）在制造6毫米缺损后显著降低（17%±5%；P = 0.0001），6毫米缺损相当于肩胛盂长度的20%。
位于3点位置、宽度等于或大于肩胛盂长度20%的骨缺损会显著降低前向稳定性。
结果表明，对于肩胛盂前方缺损至少达肩胛盂长度20%的肩关节，可能有必要重建肩胛盂凹面。
