Clinic of Orthopaedics and Traumatology, Klinikum Rechts der Isar der Technischen Universität München, Ismaninger Str. 22, 81675 Munich, Germany.
Am J Sports Med. 2010 Feb;38(2):375-82. doi: 10.1177/0363546509347105. Epub 2009 Nov 25.
Success rates in the treatment of atraumatic shoulder instability differ, and in vivo identification of the individual insufficient stabilizers is difficult.
Atraumatic shoulder instability is an inhomogeneous entity with varying alterations of the active and passive stabilizers. This might be a reason for inferior treatment results.
Case control study; Level of evidence, 3.
Shoulders of 28 healthy volunteers and both shoulders of 14 patients with atraumatic instability and multidirectional laxity were examined in different arm positions using open magnetic resonance imaging. Three-dimensional postprocessing techniques were applied to determine 3D glenoid size and retroversion, radius of the humeral head, and curvature of the glenoid. The results of static stabilizers were compared with those of glenohumeral and scapular positioning in the same patients for identification of the individual insufficient stabilizers.
The atraumatic unstable shoulders showed an increased mean retroversion on both sides, the difference being significant on the affected side (9.4 degrees +/- 4.8 degrees vs healthy 3.9 degrees +/- 1.3 degrees ; P < .05) with a range of 2.6 degrees to 16.6 degrees . The curvature analysis demonstrated a pronounced flatness of the glenoid with a significantly increased mean radius (103.8 mm vs healthy 41.7 mm). The extent of these changes varied widely among patients. Comparison of the static stabilizers with glenohumeral and scapular positioning revealed that isolated changes of the active stabilizers exist in some patients, whereas no isolated changes of passive stabilizers were found.
All active and passive stabilizers need to be analyzed in patients with atraumatic instability because the magnitude of alteration varied widely among individuals. Different combinations of alterations of the stabilizers were found. The presented technique allows for in vivo identification of the specific alterations. This is necessary for a better understanding of individual pathomechanics and for initiating a specific causal treatment.
外伤性肩关节不稳定的治疗成功率存在差异，并且难以在体内识别个体不稳定的因素。
外伤性肩关节不稳定是一种不均匀的实体，主动和被动稳定器的改变程度不同。这可能是治疗效果不佳的原因。
病例对照研究；证据水平，3 级。
在不同的手臂位置下，使用开放式磁共振成像检查 28 名健康志愿者的肩部和 14 名外伤性不稳定伴多向松弛患者的双侧肩部。应用三维后处理技术来确定三维关节盂大小和后倾、肱骨头半径和关节盂曲率。将静态稳定器的结果与同一患者的盂肱关节和肩胛定位进行比较，以确定个体不稳定的因素。
外伤性不稳定的肩部双侧均出现明显的平均后倾增加，患侧差异具有统计学意义（9.4°±4.8°比健康侧 3.9°±1.3°；P<.05），范围为 2.6°~16.6°。曲率分析显示关节盂明显变平，平均半径明显增大（103.8mm 比健康侧 41.7mm）。这些变化的程度在患者之间差异很大。将静态稳定器与盂肱关节和肩胛定位进行比较后发现，在一些患者中存在单独的主动稳定器改变，而被动稳定器没有发现单独的改变。
所有主动和被动稳定器都需要在外伤性不稳定的患者中进行分析，因为个体之间的改变程度差异很大。发现了不同稳定器改变的组合。所提出的技术允许在体内识别特定的改变。这对于更好地理解个体的病理机制和启动特定的因果治疗是必要的。
