Background:Excessive glenoid retroversion is a known risk factor for posterior shoulder instability and failure after soft tissue stabilization procedures. Whether excessive glenoid retroversion is a risk factor for failure after posterior glenoid bone grafting is unknown.Purpose:To evaluate the biomechanical effectiveness of posterior iliac crest bone grafting (ICBG) for posterior shoulder instability with increasing glenoid retroversion.Study Design:Controlled laboratory study.Methods:Six fresh-frozen cadaveric shoulders had a posterior glenoid osteotomy allowing the glenoid retroversion to be set at 0°, 10°, and 20°. At these 3 preset angles, 4 conditions were simulated consecutively on the same specimen: (1) intact glenohumeral joint, (2) posterior Bankart lesion, (3) 20% posterior glenoid bone defect, and (4) posterior ICBG. Stability was evaluated in the jerk position (60° of glenohumeral anteflexion, 60° of internal rotation) by measuring (A) posterior humeral head (HH) translation (in mm) and (B) peak translational force (in N) necessary for translation of the HH over 25% of glenoid width.Results:At 0° of retroversion, the ICBG restored posterior HH translation and peak translational force to values comparable with those of the intact condition ( P = .649 and P = .979, respectively). At 10° of retroversion, the ICBG restored the peak translational force to a value comparable with that of the intact condition (22.3 vs 24.7 N, respectively; P = .418) but showed a significant difference in posterior HH translation in comparison to the intact condition (4.5 vs 2.0 mm, respectively; P = .026). There was a significant increase in posterior HH translation and significant decrease in peak translational force with the ICBG at 20° of glenoid retroversion compared with the intact condition (posterior HH translation: 7.9 vs 2.0 mm, respectively; P < .006; peak translational force: 15.3 vs 24.7 N, respectively; P = .014).Conclusion:In this cadaveric study, posterior ICBG was able to restore stability to a level comparable to that of the native condition at 0° and to some extent at 10° of retroversion. However, posterior ICBG was not able to provide adequate stability at 20° of glenoid retroversion.Clinical Relevance:Posterior glenoid bone grafting with ICBG should be used with caution when performed in isolation in the setting of posterior instability associated with glenoid bone loss and combined glenoid retroversion of >10°.

中文翻译：

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在过度盂后倾的情况下，后关节盂骨移植在尸体后部不稳定模型中不能提供足够的稳定性


背景： 过度关节盂后倾是软组织稳定手术后后肩关节后不稳定和失败的已知危险因素。过度的关节盂后倾是否是后关节盂骨移植后失败的危险因素尚不清楚。目的： 评价髂后嵴骨移植术 （ICBG） 治疗肩关节盂后倾增加的后肩关节不稳的生物力学效果。研究设计： 对照实验室研究。方法： 6 例新鲜冰冻的尸体肩关节行后关节盂截骨术，允许关节盂后倾设置为 0° 、 10° 和 20°。在这 3 个预设角度下，在同一标本上连续模拟了 4 种情况：（1） 完整的盂肱关节，（2） 后 Bankart 病变，（3） 20% 后关节盂骨缺损，以及 （4） 后 ICBG。通过测量 （A） 肱骨后头 （HH） 平移 （mm） 和 （B） 峰值平移力 （in N） 来评估抽搐位置 （盂肱关节前屈 60°，内旋 60°） 的稳定性 HH 平移超过 25% 的关节盂宽度。结果： 在逆向 0° 时，ICBG 将后向 HH 平移和峰值平移力恢复到与完整状态相当的值 （分别为 P = .649 和 P = .979）。在回溯 10° 时，ICBG 将峰值平移力恢复到与完整状态相当的值（分别为 22.3 和 24.7 N;P = .418），但与完整情况相比，后 HH 平移显示显着差异 （分别为 4.5 和 2.0 mm;P = .026）。 与完整情况相比，在关节盂后倾 20° 时，ICBG 的后向 HH 平移显着增加，峰值平移力显着降低（后向 HH 平移：分别为 7.9 和 2.0 毫米;P < .006;峰值平移力：分别为 15.3 和 24.7 N;P = .014）。结论： 在这项尸体研究中，后 ICBG 能够在 0° 和一定程度上恢复到与逆行 10° 时天然条件相当的稳定性水平。然而，后 ICBG 无法在关节盂后倾 20° 时提供足够的稳定性。临床相关性： 在与关节盂骨丢失和联合关节盂后倾相关的后部不稳定的情况下，单独进行 ICBG 后关节盂骨移植时应谨慎使用。