Objective: 

Numerous classification systems exist to evaluate periprosthetic humerus fractures, although most are based on limited patient numbers. The Wright and Cofield system is the most widely used classification system. We sought to evaluate the interobserver and intraobserver reliabilities of this system compared with the Unified Classification System (UCS) using the largest patient sample to date.

Methods: 

This retrospective study identified patients between December 2011 and January 2021 with a periprosthetic fracture of the humerus around the stem of a shoulder arthroplasty component. Three upper extremity fellowship-trained surgeons evaluated all radiographs for stem stability, evidence of preinjury stem loosening, Wright and Cofield classification, UCS classification, and recommended treatment for each case at 2 timepoints separated by 2 months. The kappa statistic for interobserver and intraobserver reliability was calculated.

Results: 

Seventy-six patients were included. There was moderate interobserver (kappa 0.53) and substantial intraobserver (kappa 0.69) agreement when classifying stem stability after fracture. There was moderate interobserver (kappa 0.48) and intraobserver (kappa 0.60) agreement when evaluating for stem loosening before fracture. There was fair interobserver (kappa 0.29) and moderate intraobserver (kappa 0.51) agreement regarding the UCS class. There was moderate interobserver (kappa 0.41) and intraobserver (kappa 0.57) agreement regarding the proposed treatment. There was slight interobserver (kappa 0.04) and moderate intraobserver (kappa 0.44) agreement regarding the Wright and Cofield classification.

Conclusion: 

The Wright and Cofield system is less reliable than the UCS classification. A more reliable and clinically relevant classification system is needed to standardize discussion of periprosthetic proximal humerus fractures.

中文翻译：

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当前肱骨假体周围骨折分类系统的可靠性

客观的： 

存在许多评估肱骨假体周围骨折的分类系统，尽管大多数是基于有限的患者数量。Wright 和 Cofield 系统是使用最广泛的分类系统。我们试图评估该系统与使用迄今为止最大患者样本的统一分类系统 (UCS) 相比观察者间和观察者内的可靠性。

方法： 

这项回顾性研究确定了 2011 年 12 月至 2021 年 1 月期间肩关节置换假体周围肱骨假体周围骨折的患者。三名受过培训的上肢外科医生评估了所有 X 光片的柄稳定性、损伤前柄松动的证据、Wright 和 Cofield 分类、UCS 分类，并在相隔 2 个月的 2 个时间点对每个病例​​进行了推荐治疗。计算了观察者间和观察者内可靠性的 kappa 统计量。

结果： 

包括 76 名患者。对骨折后的股骨柄稳定性进行分类时，观察者间 (kappa 0.53) 和观察者内部 (kappa 0.69) 一致。在评估骨折前的股骨柄松动时，观察者间 (kappa 0.48) 和观察者内 (kappa 0.60) 的一致性适中。关于 UCS 类，观察者间 (kappa 0.29) 和观察者内 (kappa 0.51) 的一致性适中。对于提议的治疗，观察者间 (kappa 0.41) 和观察者内 (kappa 0.57) 达成了适度的一致。关于 Wright 和 Cofield 分类，观察者间（kappa 0.04）和观察者内（kappa 0.44）中度一致。

结论： 

Wright 和 Cofield 系统不如 UCS 分类可靠。需要一个更可靠和临床相关的分类系统来标准化对肱骨近端假体周围骨折的讨论。