Laboratorio di Biomeccanica e Innovazione Tecnologica, Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136, Bologna, Italy,
Int Orthop. 2014 Jun;38(6):1167-72. doi: 10.1007/s00264-014-2287-0. Epub 2014 Jan 31.
Despite the overall success of the surgical anterior cruciate ligament (ACL) reconstruction, some patients still present with instability symptoms even after the surgery, mainly due to the presence of associated lesions. At present, the pivot shift test has been reported to be the benchmark to assess rotatory knee laxity. The purpose of this study was to quantitatively evaluate rotatory knee laxity at time-zero in order to determine whether detected post-reconstruction laxity was predictable by its value measured before the reconstruction, which was hypothized to be influenced by the presence of associated lesions.
Rotatory knee laxity was retrospectively analysed in 42 patients, including two different ACL reconstructions. The maximal anterior displacement and the absolute value of the posterior acceleration reached during the reduction of the tibial lateral compartment were intra-operatively acquired by using a navigation system and identified as discriminating parameters. For each parameter, statistical linear regression analysis (line slope and intercept) was performed between pre- and post-reconstruction values.
No statistically significant influence of the initial posterior acceleration on the post-reconstruction outcome was found (line slope, p > 0.05), although a statistically significant line intercept was indeed identified (p < 0.001). A statistically significant influence on the surgery outcome was instead found for the initial value of the anterior tibial displacement (line slope = 0.39, p = 0.004), meaning that, on average, about 40 % of the post-reconstruction lateral compartment displacement could be explained by the corresponding pre-reconstruction value. Both of these findings highlighted the importance of intra-operative quantification of rotatory knee laxity to identify correct indications for the surgery.
This study provided important implications for the future possibility of defining a quantifying tool able to assess rotatory knee laxity during ACL reconstruction. This could allow detection of additional injuries to secondary restraints by easily performing rotatory knee laxity tests, which in turn could reduce post-surgical recurrence of knee instability.
尽管手术前交叉韧带（ACL）重建总体上取得了成功，但一些患者在手术后仍存在不稳定症状，主要是由于存在相关病变。目前，枢轴转移试验已被报道为评估膝关节旋转松弛度的基准。本研究旨在定量评估膝关节旋转松弛度，以确定重建后检测到的松弛度是否可通过重建前测量的值来预测，这被假设受相关病变的存在影响。
回顾性分析了 42 例患者的膝关节旋转松弛度，包括两种不同的 ACL 重建术。术中使用导航系统获取胫骨外侧间室复位过程中最大的前向位移和后向加速度的绝对值，并将其识别为判别参数。对于每个参数，均在术前和术后值之间进行了统计线性回归分析（线斜率和截距）。
尽管确实确定了统计学上显著的线截距（p<0.001），但初始后向加速度对重建后结果没有统计学显著影响（线斜率，p>0.05）。然而，初始胫骨前向位移值对手术结果有统计学显著影响（线斜率=0.39，p=0.004），这意味着平均约 40%的重建后外侧间室位移可以用相应的术前值来解释。这两种发现都强调了术中量化膝关节旋转松弛度以确定手术适应证的重要性。
本研究为未来定义一种能够评估 ACL 重建过程中膝关节旋转松弛度的定量工具提供了重要意义。这可以通过简单地进行膝关节旋转松弛度测试来检测到次要约束的附加损伤，从而减少术后膝关节不稳定的复发。
