CT评价远端桡尺关节不稳定性骨折:4种方法可信度及正常值范围分析

Computed tomography for the detection of distal radioulnar joint instability fracture: normal variation and reliability of four scoring systems

背景:CT是评估远端桡尺关节骨折的核心方法,常用4种方法来评估,即桡尺线法、半脱位比率法、中心法以及桡尺比率法。关于这4种分析方法的优缺点比较、准确性的分析、最佳的适用条件,目前尚缺乏相关研究。目的:评估桡尺线法、半脱位比率法、中心法以及桡尺比率法在诊断远端桡尺关节骨折时的一致性(可信度),计算4种方法对应的远端桡尺关节活动度的正常值范围,以便能够为远端桡尺关节骨折的诊断提供依据。方法:选取46例经保守治疗、单侧的远端桡尺关节骨折患者,共92个腕部。对每位患者的双侧腕部进行CT扫描,并分别通过2名医师阅片分析,利用桡尺线法、半脱位比率法、中心法以及桡尺比率法进行评估。利用双向随机模型,分析4种方法在观察者间及观察这自身的一致性,并计算4种方法对应的远端桡尺关节正常值范围。结果与结论:结合观察者间一致性及观察者自身一致性,中心法具有最佳的可信度(ICC分别为0.73和0.82)。每种分析方法都显示出较宽的远端桡尺关节正常值阈值。中心法在腕部旋前时的正常阈值为-0.35至-0.05,在旋后时的正常阈值为-0.12至0.20。结果说明,尽管在CT上远端桡尺关节的正常阈值范围较宽,但CT仍是评价正常腕部与创伤后腕部的可靠手段。在多种分析法中,中心法诊断远端桡尺关节骨折似乎是最可靠的,而双侧腕部的CT检测,可预防远端桡尺关节不稳定在影像学上的过度诊断。

BACKGROUND:Computed tomography(CT)is the core method for evaluating distal radioulnar joint(DRUJ)facture,including radioulnar line,subluxation ratio,epicenter and radioulnar ratio methods.There is a lack of study on the advantages and disadvantages,accuracy and optimal condition of these four methods.OBJECTIVE:To evaluate the consistency of radioulnar line,subluxation ratio,epicenter and radioulnar ratio methods in the diagnosis of DRUJ fracture,and to calculate the normal range of motion,so as to provide evidence for the diagnosis of DRUJ fracture.METHODS:Forty-six patients(92 wrists)with unilateral DRUJ fracture undergoing conservative treatment were included.CT scans of both wrists were conducted,and images were analyzed independently by two physicians using the radioulnar line,subluxation ratio,epicenter and radioulnar ratio methods.The inter-and intra-observer agreement was assessed and normal values were determined based on the uninjured wrists.RESULTS AND CONCLUSION:Inter-and intra-observer agreement was best for the epicenter method(ICC=0.73 and 0.82).Each method showed a wide normal range for normal DRUJ translation.Normal range for the epicenter method was-0.35 to-0.05 in pronation and-0.12 to 0.20 in supination.These results indicate that DRUJ translation on CT in pro-and supination can be reliably evaluated in both normal and posttraumatic wrists,however with large normal variation.The epicenter method seems most reliable.Scanning of both wrists may be helpful to prevent the radiological over diagnosis of DRUJ instability.