Steadman Philippon Research Institute, Vail, Colorado, USA.
The Steadman Clinic, Vail, Colorado, USA.
Orthop J Sports Med. 2015 Feb 23;3(2):2325967115572135. doi: 10.1177/2325967115572135. eCollection 2015 Feb.
Biomechanical studies have reported that the posterior cruciate ligament (PCL) functions as a restraint against excessive tibial internal rotation at higher degrees of knee flexion.
To investigate the use of a supine internal rotation (IR) test for the diagnosis of grade III PCL injuries. The hypothesis was that internal rotation would be greater in patients with grade III PCL injuries compared with other knee injuries and that the supine IR test would demonstrate excellent diagnostic accuracy.
Cohort study (diagnosis); Level of evidence, 2.
A consecutive series of 309 patients underwent arthroscopic and/or open knee ligament reconstruction surgery. Seven patients were excluded based on the inability to perform a side-to-side comparison of internal rotation. Tibial internal rotation was assessed bilaterally on 302 patients during examination under anesthesia by a single orthopaedic surgeon measuring tibial tubercle excursion (mm) while applying internal rotation torque. Internal rotation was graded from 0 to 4 at 60°, 75°, 90°, 105°, and 120° of knee flexion. Data were collected and stored prospectively. The optimal threshold for the supine IR test was chosen based on maximization of the Youden index. Diagnostic accuracy parameters were calculated. Multiple logistic regression models were constructed to assess the influence of other knee pathologies on diagnostic accuracy.
Examination of the 22 PCL-deficient knees demonstrated an increase in tibial internal rotation at 60°, 75°, 90°, 105°, and 120° of knee flexion. The supine IR test had a sensitivity of 95.5%, a specificity of 97.1%, a positive predictive value of 72.4%, and a negative predictive value of 99.6% for the diagnosis of grade III PCL injuries. Posterolateral corner injury had a significant interaction with the supine IR test, increasing its sensitivity and decreasing its specificity.
PCL-deficient knees demonstrated an increase in the side-to-side difference in tibial internal rotation compared with other knee pathologies. The supine IR test offers high sensitivity and specificity for grade III PCL injuries and may represent a useful adjunct for diagnosing PCL injuries.
生物力学研究表明，后交叉韧带（PCL）在膝关节更高的屈曲角度下，作为限制胫骨内旋过度的结构发挥作用。
探讨仰卧位内旋（IR）试验在诊断 III 级 PCL 损伤中的应用。假设是与其他膝关节损伤相比，III 级 PCL 损伤患者的内旋角度更大，并且仰卧 IR 试验具有出色的诊断准确性。
队列研究（诊断）；证据水平，2 级。
连续纳入 309 例接受关节镜和/或开放性膝关节韧带重建手术的患者。由于无法进行双侧内旋对比，7 例患者被排除在外。由一名骨科医生在全身麻醉下对 302 例患者进行双侧胫骨内旋评估，通过施加内旋扭矩测量胫骨结节位移（mm）。在 60°、75°、90°、105°和 120°膝关节屈曲时，对胫骨内旋进行 0 至 4 级分级。数据被前瞻性收集和存储。根据 Youden 指数的最大化选择仰卧 IR 试验的最佳阈值。计算诊断准确性参数。构建多元逻辑回归模型，以评估其他膝关节病变对内旋试验诊断准确性的影响。
对 22 例 PCL 缺失的膝关节进行检查，发现膝关节在 60°、75°、90°、105°和 120°时胫骨内旋增加。仰卧 IR 试验对 III 级 PCL 损伤的诊断具有 95.5%的敏感性、97.1%的特异性、72.4%的阳性预测值和 99.6%的阴性预测值。后外侧角损伤与仰卧 IR 试验有显著的交互作用，增加了其敏感性，降低了其特异性。
与其他膝关节病变相比，PCL 缺失的膝关节显示出胫骨内旋的双侧差异增加。仰卧 IR 试验对 III 级 PCL 损伤具有较高的敏感性和特异性，可能是诊断 PCL 损伤的有用辅助手段。
