Department of Orthopaedics and Traumatology, Escola Paulista de Medicina, Federal University of São Paulo, São Paulo, SP, Brazil.
Hospital Israelita Albert Einstein, São Paulo, SP, Brazil.
Knee Surg Sports Traumatol Arthrosc. 2019 Sep;27(9):2927-2935. doi: 10.1007/s00167-018-5011-6. Epub 2018 Jun 8.
Understanding the pathomechanics of a bicruciate injury (BI) is critical for its correct diagnosis and treatment. The purpose of this biomechanical study aims to quantify the effects of sequential sectioning of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) bundles on knee laxity.
Twelve cadaveric knees (six matched pairs) were used. Knee laxity measurements consisted of neutral tibial position, anterior-posterior translation, internal-external rotation, and varus-valgus angulation in different conditions: intact, ACL cut, incomplete BI (divided into two groups: anterolateral (AL) bundle intact or posteromedial (PM) bundle intact) and complete bicruciate tear. Data were collected using a Microscribe system at 0°, 30°, 60°, and 90° of knee flexion.
In comparison to the intact knees, incomplete BI and complete BI showed a significant increase of total antero-posterior tibial translation. The largest significant increase was observed at 90° of flexion after a complete bicruciate resection (p < 0.001). A threshold difference greater than 15 mm from the intact could be used to identify a complete BI from an incomplete BI evaluating the total antero-posterior translation at 90°. All sectioned states had significant increases compared with the intact condition in internal-external rotation and varus-valgus stability at all tested flexion angles.
Both incomplete and complete BI led to an important AP translation instability at all angles; however, full extension was the most stable position at all injured models. Total antero-posterior translation at 90° of knee flexion over 15 mm, in comparison to the intact condition, was indicative of a complete BI. Since the appropriate assessment of a combined ACL and PCL lesion remains a challenge, this study intends to assist its diagnosis. As BI's main antero-posterior instability occurred at 90°, a total antero-posterior drawer test is proposed to evaluate BI in the clinical setting. Total antero-posterior translation at 90° > 15 mm, in comparison to the intact condition or the contra-lateral non-injured knee, can be used to identify a complete from an incomplete BI.
了解双交叉损伤（BI）的病理机制对于正确诊断和治疗至关重要。本生物力学研究的目的是定量分析前交叉韧带（ACL）和后交叉韧带（PCL）束的连续切断对膝关节松弛度的影响。
使用 12 个尸体膝关节（6 对匹配）。膝关节松弛度测量包括中立位胫骨位置、前-后平移、内-外旋转以及不同情况下的内-外翻角度：完整、ACL 切断、不完全 BI（分为两组：前外侧（AL）束完整或后内侧（PM）束完整）和完全双十字韧带撕裂。使用 Microscribe 系统在 0°、30°、60°和 90°膝关节屈曲时收集数据。
与完整膝关节相比，不完全 BI 和完全 BI 的总前-后胫骨平移明显增加。在完全双十字韧带切除后，90°屈曲时观察到最大的显著增加（p<0.001）。在 90°时，从完整膝关节到不完全 BI 的总前-后平移的 15mm 以上的阈值差异可用于识别完全 BI。与完整状态相比，所有节段状态在所有测试的屈曲角度下，内-外旋转和内-外翻稳定性都有显著增加。
不完全和完全 BI 都导致所有角度的重要 AP 平移不稳定；然而，在所有受伤模型中，完全伸展是最稳定的位置。与完整状态相比，膝关节 90°时的总前-后平移超过 15mm 提示完全 BI。由于准确评估 ACL 和 PCL 联合损伤仍然具有挑战性，本研究旨在协助其诊断。由于 BI 的主要前-后不稳定发生在 90°，因此建议在临床环境中使用总前-后抽屉试验来评估 BI。与完整状态或对侧未受伤膝关节相比，90°时的总前-后平移超过 15mm 可用于识别完全 BI 和不完全 BI。
