Shoulder, Elbow and Orthopaedic Sports Medicine, Department of Orthopaedic Surgery and Traumatology, Inselspital, Bern University Hospital, University of Bern, Freiburgstrasse 18, 3010, Bern, Switzerland.
Department of Radiology, Inselspital, Bern University HospitalUniversity of Bern, Freiburgstrasse 18, 3010, Bern, Switzerland.
Knee Surg Sports Traumatol Arthrosc. 2018 Jan;26(1):125-135. doi: 10.1007/s00167-017-4579-6. Epub 2017 May 25.
The aim of this study was to identify the most accurate and reliable quantitative radiographic parameters for assessing vertical and horizontal instability in different Rockwood grades of acromioclavicular joint (ACJ) separations. Furthermore, the effect of projectional variation on these parameters was investigated in obtaining lateral Alexander view radiographs.
A Sawbone model of a scapula with clavicle was mounted on a holding device, and acromioclavicular dislocations as per the Rockwood classification system were simulated with the addition of horizontal posterior displacement. Projectional variations for each injury type were performed by tilting/rotating the Sawbone construct in the coronal, sagittal or axial plane. Radiographic imaging in the form of an anterior-posterior Zanca view and a lateral Alexander view were taken for each injury type and each projectional variation. Five newly defined radiographic parameters for assessing horizontal and vertical displacement as well as commonly used coracoclavicular distance view were measured. Reliability, validity and the effect of projectional variation were investigated for these radiographic measurements.
All radiographic parameters showed excellent intra- and interobserver reliability. The validity was excellent for the acromial centre line to dorsal clavicle (AC-DC) in vertical displacement and for the glenoid centre line to posterior clavicle (GC-PC) in horizontal displacement, whilst the remaining measurements showed moderate validity. For AC-DC and GC-PC, convergent validity expressed strong correlation to the effective distance and discriminant validity demonstrated its ability to differentiate between various grades of ACJ dislocations. The effect of projectional variation increased with the degree of deviation and was maximal (3 mm) for AC-DC in 20° anteverted malpositioning and for GC-PC in 20° retroverted malpositioning.
AC-DC and the GC-PC are two novel quantitative radiographic parameters of vertical and horizontal instability in ACJ dislocations that demonstrate excellent reliability and validity with reasonable inertness to malpositioning. The use of AC-DC for assessing vertical displacement and GC-PC for assessing horizontal displacement in a single Alexander view is recommended to guide the appropriate management of ACJ dislocations. A better appreciation of the degree of horizontal instability, especially in lower Rockwood grades (II, III) of ACJ dislocations, may improve management of these controversial injuries.
本研究旨在确定评估不同 Rockwood 分级肩锁关节（ACJ）分离的垂直和水平不稳定的最准确和可靠的定量影像学参数。此外，还研究了在获得侧位 Alexander 视图 X 线片时，投照变异对这些参数的影响。
将肩胛骨和锁骨的 Sawbone 模型安装在固定装置上，并通过在冠状面、矢状面或轴面倾斜/旋转 Sawbone 结构来模拟 Rockwood 分类系统中的肩锁关节脱位。对每种损伤类型进行投照变异，形成前后 Zanca 视图和侧位 Alexander 视图的影像学图像。对每种损伤类型和每种投照变异都进行了测量。测量了 5 种新定义的用于评估水平和垂直移位的影像学参数以及常用的喙锁间距视图。对这些影像学测量的可靠性、有效性和投照变异的影响进行了研究。
所有影像学参数均表现出良好的组内和组间可靠性。在垂直移位方面，肩峰中心到锁骨背侧（AC-DC）的有效性为优秀，在水平移位方面，关节盂中心到锁骨后侧（GC-PC）的有效性为优秀，而其余测量值的有效性为中度。对于 AC-DC 和 GC-PC，收敛有效性表达为与有效距离的强相关性，判别有效性证明其能够区分不同等级的 ACJ 脱位。投照变异的影响随着偏差程度的增加而增加，在 20°前旋错位时，AC-DC 的影响最大（3mm），在 20°后旋错位时，GC-PC 的影响最大（3mm）。
AC-DC 和 GC-PC 是评估 ACJ 脱位垂直和水平不稳定的两种新的定量影像学参数，它们具有良好的可靠性和有效性，并且对投照位置的变化具有合理的惰性。建议在单个 Alexander 视图中使用 AC-DC 评估垂直移位，使用 GC-PC 评估水平移位，以指导 ACJ 脱位的适当治疗。更好地了解水平不稳定的程度，特别是在 Rockwood 分级较低（II、III）的 ACJ 脱位中，可能会改善这些有争议的损伤的治疗。
