Volume Loss and Recovery in Bovine Knee Meniscus Loaded in Circumferential Tension

Area of Science:

• Biomechanics
• Biomedical Engineering
• Orthopedics

Background:

• The knee meniscus plays a vital role in load distribution and friction reduction within the knee joint.
• Meniscal function is significantly influenced by load-induced volume changes, which affect fluid pressure and load support.
• Existing literature presents inconsistencies regarding the meniscus' volumetric strain under tensile loading.

Purpose of the Study:

• To directly measure the three-dimensional (3D) volumetric strain of the knee meniscus under uniaxial tension.
• To quantify the rate of volume recovery in the meniscus upon unloading from tensile load.
• To contribute to a comprehensive understanding of knee meniscus fluid dynamics and load-bearing mechanisms.

Main Methods:

• Bovine knee meniscus samples were subjected to controlled uniaxial tensile loading.
• Biplanar imaging techniques were employed to capture 3D volume changes during loading and unloading.
• Volumetric strain and recovery rates were calculated based on the imaging data.

Main Results:

• Tensile loading of the knee meniscus resulted in volumetric contraction, similar to compression.
• The rate of volume recovery upon unloading was observed to be faster than the rate of volume loss during loading at physiologic strains.
• Direct measurement of 3D volume change under tension provides novel data for meniscal biomechanics.

Conclusions:

• Both compression and tension induce volumetric contraction in the knee meniscus, leading to fluid outflow.
• The meniscus exhibits a rapid recovery of volume upon unloading, which is critical for its load-support function.
• These findings advance the understanding of knee meniscus mechanics, fluid flow, and injury prevention.