Mukherjee N, Wayne J S
Department of Biomedical Engineering, Virginia Commonwealth University, Richmond 23298-0694, USA.
J Biomech Eng. 1998 Oct;120(5):620-4. doi: 10.1115/1.2834753.
Experimental measurements in conjunction with theoretical predictions were used to determine the extent of load supported by the fluid phase of cartilage at the articular surface. The u-p finite element model was used to simulate the loading of six separate porcine knee joints and to predict surface deformations of the cartilage layer on the lateral femoral condyle. Representative geometry for the condyle, contact pressures, and intrinsic material properties of the cartilage layer were supplied from experimental measures (see Part I). The u-p finite element predictions for surface deformations of the cartilage layer were obtained for several load partitioning states between the solid and fluid phases of cartilage at the articular surface. These were then compared to actual surface deformations obtained experimentally. It appeared from the comparison that approximately 75 percent of the applied load was borne by the fluid phase at the articular surface under this loading regime. This was qualitatively in agreement with the hypothesis that an applied load to articular joints is partitioned at the surface to the two phases according to the surface area ratios of the solid and fluid phases. It appeared that the solid phase was shielded from the total applied stress on the articular surface by the fluid and could be a reason for the excellent durability of the tissue under the demanding conditions in a diarthrodial joint.
结合理论预测进行的实验测量，用于确定关节表面软骨液相所承受负荷的程度。采用u-p有限元模型模拟六个单独猪膝关节的负荷，并预测股骨外侧髁软骨层的表面变形。髁的代表性几何形状、接触压力以及软骨层的固有材料特性均来自实验测量（见第一部分）。针对关节表面软骨固相与液相之间的几种负荷分配状态，获得了软骨层表面变形的u-p有限元预测结果。然后将这些结果与实验获得的实际表面变形进行比较。从比较结果来看，在这种加载方式下，关节表面约75%的外加负荷由液相承担。这在定性上与以下假设一致：施加于关节的负荷在表面根据固相与液相的表面积比分配到两相。看来固相通过液相免受关节表面总外加应力的影响，这可能是该组织在动关节苛刻条件下具有出色耐久性的一个原因。
