IIa Clinica Ortopedica e Traumatologica, IRCCS Istituto Ortopedico Rizzoli, Bologna, Italy.
Am J Sports Med. 2021 Mar;49(3):649-655. doi: 10.1177/0363546520982002. Epub 2021 Jan 15.
The lateral femoral notch sign (LNS) is a bony impression on the lateral femoral condyle correlated with anterior cruciate ligament (ACL) injury. Its presence is associated with lateral meniscal injury and higher cartilage degradation on the lateral femoral condyle.
PURPOSE/HYPOTHESIS: The purpose was to investigate the effect of the presence and magnitude of LNS on rotatory instability. The hypothesis was that a positive LNS is correlated with a high-grade pivot shift (PS).
Cross-sectional study; Level of evidence, 3.
A total of 90 consecutive patients with complete ACL tears between 2013 and 2017 underwent intraoperative kinematic evaluation with the surgical navigation system and were included in the present study. The same surgeon performed a standardized PS under anesthesia. The PS was quantified through the acceleration of the lateral compartment during tibial reduction (PS ACC) and the internal-external rotation (PS IE). Presence and depth of LNS were evaluated on sagittal magnetic resonance images (1.5-T).
In 47 patients, the LNS was absent; in 33, the LNS depth was between 1 mm and 2 mm; and in 10 patients, it was deeper than 2 mm. Patients with a notch deeper than 2 mm showed increased PS ACC and PS IE compared with the group without the LNS. However, no significant differences were present between the group with a notch between 1 and 2 mm and the patients without LNS. Receiver operating characteristic curve analysis showed that 2 mm was the most predictive cutoff value to identify the "high-grade rotatory instability" group, with an accuracy of 77.8% and 74.4% and a specificity of 95.5% and 93.9% referred to the PS ACC and PS IE, respectively.
The presence of a lateral LNS deeper than 2 mm could be used for the preoperative identification of patients with a high risk of increased rotatory instability.
外侧股骨切迹征（LNS）是外侧股骨髁上的骨性凹陷，与前交叉韧带（ACL）损伤有关。其存在与外侧半月板损伤和外侧股骨髁软骨退变程度较高有关。
目的/假设：本研究旨在探讨 LNS 的存在和严重程度对旋转不稳定性的影响。假设是阳性 LNS 与高等级枢轴转移（PS）相关。
横断面研究；证据水平，3 级。
2013 年至 2017 年间，共 90 例连续 ACL 撕裂患者接受了手术导航系统的术中运动学评估，并纳入本研究。同一位外科医生在麻醉下进行了标准化的 PS。PS 通过胫骨复位时外侧间隔的加速度（PS ACC）和内外旋转（PS IE）进行量化。在矢状面磁共振图像（1.5-T）上评估 LNS 的存在和深度。
在 47 例患者中，LNS 不存在；在 33 例患者中，LNS 深度在 1 至 2 毫米之间；在 10 例患者中，LNS 深度大于 2 毫米。LNS 深度大于 2 毫米的患者与无 LNS 的患者相比，PS ACC 和 PS IE 增加。然而，LNS 深度在 1 至 2 毫米之间的患者与无 LNS 的患者之间无显著差异。受试者工作特征曲线分析显示，2 毫米是识别“高等级旋转不稳定”组的最具预测性的截断值，其准确性分别为 77.8%和 74.4%，特异性分别为 95.5%和 93.9%，用于 PS ACC 和 PS IE。
外侧 LNS 深度大于 2 毫米可用于术前识别高旋转不稳定风险患者。
