Background

The effect of tibiofemoral geometry on musculoskeletal function is important to movement biomechanics.

Research question

We hypothesised that tibiofemoral geometry determines tibiofemoral motion and musculoskeletal function. We then aimed at 1) modelling tibiofemoral motion during normal activity as a function of tibiofemoral geometry in healthy adults; and 2) quantifying the effect of tibiofemoral geometry on musculoskeletal function.

Methods

We used motion data for six activity types and CT images of the knee from 12 healthy adults. Geometrical variation of the tibia and femoral articular surfaces were measured in the CT images. The geometry-based tibiofemoral motion was calculated by fitting a parallel mechanism to geometrical variation in the cohort. Matched musculoskeletal models embedding the geometry-based tibiofemoral joint motion and a common generic tibiofemoral motion of reference were generated and used to calculate joint angles, net joint moments, muscle and joint forces for the six activities analysed. The tibiofemoral model was validated against bi-planar fluoroscopy measurements for walking for all the six planes of motion. The effect of tibiofemoral geometry on musculoskeletal function was the difference between the geometry-based model and the model of reference.

Results

The geometry-based tibiofemoral motion described the pattern and the variation during walking for all six motion components, except the pattern of anterior tibial translation. Tibiofemoral geometry had moderate effect on cohort-averages of musculoskeletal function (R² = 0.60–1), although its effect was high in specific instances of the model, outputs and activities analysed, reaching 2.94 BW for the ankle reaction force during stair descent. In conclusion, tibiofemoral geometry is a major determinant of tibiofemoral motion during walking.

Significance

Geometrical variations of the tibiofemoral joint are important for studying musculoskeletal function during normal activity in specific individuals but not for studying cohort averages of musculoskeletal function. This finding expands current knowledge of movement biomechanics.

中文翻译：

---

正常活动期间胫股几何学与肌肉骨骼功能之间的关系。

背景

胫股几何形状对肌肉骨骼功能的影响对运动生物力学很重要。

研究问题

我们假设胫股的几何形状决定了胫股的运动和肌肉骨骼功能。然后我们的目标是：1）在健康成年人中，将正常活动期间的胫股运动建模为胫股几何形状的函数；2）量化胫股几何形状对肌肉骨骼功能的影响。

方法

我们使用了来自12位健康成年人的六种活动类型的运动数据和膝盖的CT图像。在CT图像中测量了胫骨和股骨关节表面的几何变化。通过将平行机制拟合到队列中的几何变化来计算基于几何的胫股运动。生成了嵌入了基于几何的胫股关节运动和通用的通用股胫运动参考的匹配的肌肉骨骼模型，并用于计算分析的六个活动的关节角度，净关节力矩，肌肉和关节力。胫骨股骨模型已针对双平面透视检查在所有六个运动平面上行走进行了验证。胫股几何对肌肉骨骼功能的影响是基于几何的模型和参考模型之间的差异。

结果

基于几何形状的胫股运动描述了步行过程中所有六个运动成分的模式和变化，除了前胫骨平移的模式。胫股几何学对平均队列的肌肉骨骼功能有中等程度的影响（R ²  = 0.60-1），尽管在特定的模型实例，分析的输出和活动中其影响很高，楼梯下降时踝部反作用力达到2.94 BW。总之，胫股几何形状是步行过程中胫股运动的主要决定因素。

意义

胫股关节的几何变化对于研究特定个体在正常活动期间的肌肉骨骼功能很重要，但对于研究肌肉骨骼功能的同类平均水平则不重要。这一发现扩展了目前对运动生物力学的认识。