Laboratory for Movement Biomechanics, Institute for Biomechanics, ETH Zürich, Zürich, Switzerland.
Human Performance Lab, Schulthess Clinic, Zürich, Switzerland.
J Bone Joint Surg Am. 2021 Sep 1;103(17):1620-1627. doi: 10.2106/JBJS.20.01311.
Improved knowledge of in vivo function of the collateral ligaments is essential for enhancing rehabilitation and guiding surgical reconstruction as well as soft-tissue balancing in total knee arthroplasty. The aim of this study was to quantify in vivo elongation patterns of the collateral ligaments throughout complete cycles of functional activities.
Knee kinematics were measured using radiographic images captured with a mobile fluoroscope while healthy subjects performed level walking, downhill walking, and stair descent. The registered in vivo tibiofemoral kinematics were then used to drive subject-specific multibody knee models to track collateral ligament elongation.
The elongation patterns of the medial collateral ligament varied distinctly among its bundles, ranging from lengthening of the anterior fibers to shortening of the posterior bundle with increases in the knee flexion angle. The elongation patterns of the lateral collateral ligament varied considerably among subjects. It showed an average 4% shortening with increasing flexion until 60% to 70% of the gait cycle, and then recovered during the terminal-swing phase until reaching its reference length (defined at heel strike).
The observed nonuniform elongation of the medial collateral ligament bundles suggests that single-bundle reconstruction techniques may not fully restore healthy ligament function. Moreover, the observed ligament elongation patterns indicate greater varus than valgus laxity in the loaded knee.
Through providing key knowledge about the in vivo elongation patterns of the collateral ligaments throughout complete cycles of functional activities, this study offers in vivo evidence for benchmarking ligament reconstruction and soft-tissue balancing in total knee arthroplasty.
深入了解侧副韧带的体内功能对于增强康复效果、指导手术重建以及全膝关节置换术中软组织平衡至关重要。本研究旨在定量分析侧副韧带在各种功能活动周期中的体内伸长模式。
使用移动透视仪拍摄的放射图像测量膝关节运动学，让健康受试者进行水平行走、下坡行走和下楼梯。然后，将注册的体内胫股运动学用于驱动特定于个体的多体膝关节模型，以跟踪侧副韧带的伸长。
内侧副韧带的各束的伸长模式差异明显，随着膝关节弯曲角度的增加，前纤维变长，而后束变短。外侧副韧带的伸长模式在受试者之间差异很大。它在屈曲增加到步态周期的 60%至 70%时显示出平均 4%的缩短，然后在终末期摆动阶段恢复，直到达到其参考长度（定义为足跟接触时）。
观察到的内侧副韧带束的非均匀伸长表明，单束重建技术可能无法完全恢复健康韧带的功能。此外，观察到的韧带伸长模式表明，在负重膝关节中，内翻松弛度大于外翻松弛度。
通过提供关于侧副韧带在完整功能活动周期中的体内伸长模式的关键知识，本研究为全膝关节置换术中的韧带重建和软组织平衡提供了体内证据。
