Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Am J Sports Med. 2021 Apr;49(5):1279-1285. doi: 10.1177/0363546521995199. Epub 2021 Mar 3.
Previous studies have stated that closely matching the size of the anterior cruciate ligament (ACL) insertion site footprint is important for biomechanical function and clinical stability after ACL reconstruction. However, the ACL varies widely regarding the area of femoral insertion, tibial insertion, and midsubstance of ACL, and reconstructing the insertion site area with a uniform diameter graft can result in a cross-sectional area that is greater than that of the midsubstance of the native ACL. Therefore, understanding the effect of relative graft size in ACL reconstruction on knee biomechanics is important for surgical planning.
To assess how the percentage of femoral insertion site affects knee biomechanics in single- and double-bundle ACL reconstruction.
Controlled laboratory study.
A total of 14 human cadaveric knees were scanned with magnetic resonance imaging and tested using a robotic system under an anterior tibial load and a combined rotational load. In total, 7 knee states were evaluated: intact ACL; deficient ACL; single-bundle ACL reconstruction with approximate graft sizes 25% (small), 50% (medium), and 75% (large) of the femoral insertion site; and double-bundle reconstruction of approximately 50% (medium) and 75% (large) of the femoral insertion site, based on the ratio of the cross-sectional area of the graft to the area of the femoral ACL insertion site determined by magnetic resonance imaging.
Anterior tibial translation was not significantly larger than the intact state in single-bundle and double-bundle medium graft reconstructions ( > .05) and was significantly greater in the single-bundle small graft reconstruction ( < .05). Anterior knee translation in single-bundle medium graft and large graft reconstructions was not statistically different ( > .05). In contrast, the anterior tibial translation for double-bundle large graft reconstruction was significantly smaller than for double-bundle medium graft reconstruction at low flexion angles ( < .05). The single-bundle small graft force was significantly different from the intact ACL in situ force ( < .05). The graft force with double-bundle large reconstruction was significantly greater than that with the double-bundle medium reconstruction ( < .05) but was not significantly different from that of the intact ACL ( > .05).
Knee biomechanics with a single-bundle small graft tended to be significantly different from those of the intact knee. In the kinematic and kinetic data for the single- and double-bundle medium graft reconstruction, only the anterior translation at full extension for the single-bundle reconstruction was significantly different (lower) from that of intact knee. This was a time zero study.
This study can provide surgeons with guidance in selecting the graft size for ACL reconstruction.
先前的研究表明，前交叉韧带（ACL）插入部位的大小匹配对于 ACL 重建后的生物力学功能和临床稳定性非常重要。然而，ACL 在股骨插入部位、胫骨插入部位和 ACL 中体的面积方面差异很大，用统一直径的移植物重建插入部位区域可能会导致横截面积大于 ACL 中体的横截面积。因此，了解 ACL 重建中相对移植物大小对膝关节生物力学的影响对于手术规划很重要。
评估单束和双束 ACL 重建中股骨插入部位百分比如何影响膝关节生物力学。
对照实验室研究。
对 14 个人体尸体膝关节进行磁共振成像扫描，并使用机器人系统在胫骨前负荷和联合旋转负荷下进行测试。总共评估了 7 种膝关节状态：完整 ACL；ACL 缺失；单束 ACL 重建，移植物大小约为股骨插入部位的 25%（小）、50%（中）和 75%（大）；以及双束重建，大约为股骨插入部位的 50%（中）和 75%（大），基于磁共振成像确定的移植物的横截面积与股骨 ACL 插入部位的面积之比。
单束和双束中等移植物重建的胫骨前移位均不明显大于完整状态（>.05），而单束小移植物重建的胫骨前移位明显更大（<.05）。单束中等和大移植物重建的膝关节前向位移在统计学上无差异（>.05）。相比之下，在低弯曲角度下，双束大移植物重建的胫骨前位移明显小于双束中等移植物重建（<.05）。单束小移植物的力明显不同于原位 ACL 的力（<.05）。双束大重建的移植物力明显大于双束中等重建（<.05），但与完整 ACL 无显著差异（>.05）。
单束小移植物的膝关节生物力学明显不同于完整膝关节。在单束和双束中等移植物重建的运动学和动力学数据中，只有单束重建的完全伸展时的前向位移明显（更低）不同于完整膝关节。这是一项时间零研究。
本研究可为外科医生选择 ACL 重建的移植物大小提供指导。
