Knecht Sven, Luechinger Roger, Boesiger Peter, Stüssi Edgar
Institute for Biomechanics, ETH Zurich, Wolfgang-Pauli-Strasse 10, Zurich, Switzerland.
Biomed Tech (Berl). 2008 Dec;53(6):285-91. doi: 10.1515/BMT.2008.045.
The mechanical property of articular cartilage determines to a great extent the functionality of diarthrodial joints. Consequently, the early detection of mechanical and, thus, functional changes of cartilage is crucial for preventive measures to maintain the mobility and the quality of life of individuals. An alternative to conventional mechanical testing is the inverse finite element approach, enabling non-destructive testing of the tissue. We evaluated a method for the assessment of the equilibrium material properties of the patellar cartilage based on magnetic resonance imaging during patellofemoral compression. We performed ex vivo testing of two equine patellas with healthy cartilage, one with superficial defects, and one with synthetically degenerated cartilage to simulate a pre-osteoarthritic stage. Static compression with 400 N for 2 h resulted in morphological changes comparable to physiological in vivo deformations in humans. We observed a decrease of the equilibrium Young's modulus of the degenerated cartilage by -59%, which was in the range of the results from indentation (-74%) and confined compression tests (-58%). With the reported accuracy of magnetic resonance imaging and its reproducibility, the results indicate the potential to measure differences in Young's modulus with regard to cartilage degeneration and consequently to distinguish between healthy and pre-osteoarthritic cartilage.
关节软骨的力学性能在很大程度上决定了滑膜关节的功能。因此，早期检测软骨的力学变化以及功能变化对于采取预防措施以维持个体的活动能力和生活质量至关重要。传统力学测试的一种替代方法是逆有限元法，它能够对组织进行无损检测。我们评估了一种基于磁共振成像在髌股关节压缩过程中评估髌软骨平衡材料特性的方法。我们对两块具有健康软骨的马髌骨、一块有浅表缺损的髌骨以及一块模拟骨关节炎前期阶段的人工退变软骨的髌骨进行了离体测试。以400 N的力进行2小时的静态压缩导致的形态变化与人类体内生理变形相当。我们观察到退变软骨的平衡杨氏模量下降了59%，这与压痕试验（-74%）和受限压缩试验（-58%）的结果范围相符。鉴于所报道的磁共振成像的准确性及其可重复性，这些结果表明有潜力测量与软骨退变相关的杨氏模量差异，从而区分健康软骨和骨关节炎前期软骨。
