Department of Orthopaedic Surgery, National University Hospital, Singapore.
Department of Orthopaedic Surgery, National University Hospital, Singapore.
J Shoulder Elbow Surg. 2021 Sep;30(9):2191-2196. doi: 10.1016/j.jse.2021.01.016. Epub 2021 Feb 12.
Controversies for treatment of acromioclavicular joint injuries in particular type III injuries may be partially attributed to the lack of a standardized method of radiography and measurement technique. Previous studies looking at the Rockwood classification showed poor inter- and intraobserver reliability (Kappa value approximately 0.20-0.50). We hypothesized that the use of unilateral instead of bilateral acromioclavicular joint radiographs was the cause of this finding. In this article, we standardized the methodology to perform the radiograph and to measure the coracoclavicular distances. We designed the study to focus on the reliability of differentiating type III and type V injuries.
A standardized radiographic protocol for bilateral Zanca view was established in our institution. All patients who underwent this radiographic examination over a 3-year period were reviewed. Radiographs of 55 patients with significant (type III or V) injury met the inclusion criteria. For the interobserver reliability, a retrospective radiographic review was performed by 6 orthopedic surgeons and graded as either type III or V. For intraobserver reliability, a similar process was repeated by 3 observers after a period of 6 weeks.
Going by the majority agreement of the 6 reviewers, there were 34 type III injuries and 19 type V injuries. The Fleiss kappa for interobserver reliability was calculated to be 0.624. The Cohen kappa for intraobserver reliability was calculated to be 0.696.
The use of a standardized radiographic protocol-taking bilateral Zanca views on the same radiographic plate-would help eliminate a significant amount of variability and improve the reliability of classifying acromioclavicular joint injuries using the Rockwood classification, which uses a relative measure to the contralateral site as its definition criteria. Other possible sources of poor reliability may include the masking of injuries by muscle spasm, resulting in a misdiagnosis of a high-grade injury as a lower-grade one and the possible need to subclassify type III injuries.
Reliability of the Rockwood classification can be improved through the use of a standardized radiographic protocol to improve the detection of vertical instability. Similar to Rockwood dividing up Tossy grade 3 injuries when he noted the differential outcome and intervention, Rockwood type III injuries would likely require further subclassification as it remains an anomalous tool with high variability. Further studies are required to understand the pathologic basis of transition of type III into type V injury.
对于特定类型 III 型肩锁关节损伤的治疗存在争议，部分原因可能是缺乏标准化的影像学检查和测量技术。先前研究 Rockwood 分类时发现，其观察者间和观察者内可信度（kappa 值约为 0.20-0.50）较差。我们假设使用单侧而非双侧肩锁关节 X 线片是造成这种结果的原因。在本文中，我们对 X 线片的拍摄方法和喙锁间距的测量方法进行了标准化。本研究重点关注区分 III 型和 V 型损伤的可信度。
我们在机构内建立了双侧 Zanca 位 X 线摄影的标准化方案。对 3 年内进行该影像学检查的所有患者进行了回顾。对 55 例具有明显（III 型或 V 型）损伤的患者 X 线片进行了分析，符合纳入标准。为了评估观察者间可信度，由 6 名骨科医生对 X 线片进行回顾性分析，判断为 III 型或 V 型。为了评估观察者内可信度，3 名观察者在 6 周后重复该过程。
根据 6 名评审者的多数意见，34 例为 III 型损伤，19 例为 V 型损伤。观察者间可信度的 Fleiss kappa 值为 0.624。观察者内可信度的 Cohen kappa 值为 0.696。
使用标准化 X 线摄影方案（同一 X 线片上拍摄双侧 Zanca 位）有助于消除大量的变异性，并提高使用 Rockwood 分类对肩锁关节损伤进行分类的可信度，Rockwood 分类使用相对测量值作为对侧部位的定义标准。其他可能导致可信度较差的原因可能包括肌肉痉挛导致的损伤隐匿，从而将高等级损伤误诊为低等级损伤，以及可能需要对 III 型损伤进行进一步分类。
通过使用标准化 X 线摄影方案来提高对垂直不稳定的检测，可提高 Rockwood 分类的可信度。类似于 Rockwood 在注意到不同的结果和干预时对 Tossy 3 级损伤进行细分一样，Rockwood III 型损伤可能需要进一步分类，因为它仍然是一种具有高度变异性的异常工具。需要进一步研究来了解 III 型向 V 型损伤转变的病理基础。
