Purpose

To evaluate the diagnostic value of stress radiography and determine the cutoff values for high-grade anterolateral rotatory laxity in complete anterior cruciate ligament (ACL)-deficient knees at different positions.

Methods

Forty-two patients with complete ACL rupture (group 1) and 37 normal subjects (group 2) were prospectively enrolled. The amount of anterior translation in the medial (MM) and lateral (LL) distance compartments and the difference between them (LL-MM distance) were measured using stress radiography at 30°, 45°, 60°, and 90° positions. The area under the receiver operating characteristic curve (AUC) was assessed for the presence of a high-grade (grade > 2) pivot shift.

Results

The MM and LL distances in group 1 were significantly different at 30° and 45° positions (P < 0.05). The AUC of the MM (AUC, 0.903) and LL (AUC, 0.901) distances at the 30° position was significantly higher than that of the other positions (P = 0.000); however, the cutoff values were different to diagnose ACL injury (MM vs. LL, 3.1 mm vs. 5.4 mm). A 2.1-mm cutoff for the LL-MM distance showed 78.4% sensitivity and 90.3% specificity for detecting the presence of a high-grade pivot shift (AUC = 0.905, P = 0.000).

Conclusion

The cutoff values of stress radiography differed according to anatomical references and knee flexion positions. Stress radiography of a 2.1 mm difference in LL-MM distance at 30° of knee flexion can be a reliable method for high-grade rotatory laxity in complete ACL-injured knees.

Level of evidence

Level 1, diagnostic study.

中文翻译：

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膝关节屈曲30°时的应力射线照相术是可靠的评估工具，可用于对完全ACL受伤的膝盖进行高级旋转松弛。

目的

若要评估应力射线照相的诊断价值，并确定完全前交叉韧带（ACL）缺损的膝盖在不同位置的高级前外侧旋转松弛的临界值。

方法

前瞻性纳入了42例ACL完全破裂的患者（第1组）和37例正常受试者（第2组）。使用应力射线照相术在30°，45°，60°和90°位置测量内侧（MM）和外侧（LL）距离隔室中的前移量以及它们之间的差（LL-MM距离）。评估接收器工作特性曲线（AUC）下的区域是否存在高等级（等级> 2）枢轴位移。

结果

第一组的MM和LL距离在30°和45°位置上有显着差异（P  <0.05）。在30°位置的MM（AUC，0.903）和LL（AUC，0.901）距离的AUC显着高于其他位置（P  = 0.000）；但是，用于诊断ACL损伤的临界值是不同的（MM与LL，3.1 mm与5.4 mm）。LL-MM距离的2.1毫米截止值显示了78.4％的灵敏度和90.3％的特异性，可检测出是否存在高级枢轴位移（AUC = 0.905，P  = 0.000）。

结论

应力射线照相的临界值根据解剖学参考和膝盖屈曲位置而有所不同。膝关节屈曲30°时LL-MM距离相差2.1 mm的应力射线照相术可以成为对完全ACL受伤的膝盖进行高等级旋转松弛的可靠方法。

证据水平

1级，诊断研究。