Evaluation of pre-stresses in the menisci of human knee joint using microindentation

To evaluate the pre-stress in the menisci of a human knee joint, the technique of microindentation was adopted. Five specimens each for lateral and medial menisci attached to the tibia were prepared from the knee joints of Korean cadavers to represent the pre-stress state of the meniscus. To create test specimens for the stress-free state of the meniscus, each meniscus was resected from the tibia and cut into three parts, which were subsequently attached to a metal plate. Indentations were carried out in each meniscus in both the pre-stress state and the stress-free state. The pre-stresses in the menisci were evaluated using the load-versus-depth curves. Compressive pre-stresses were found in the menisci. For each indentation region, the pre-stresses in the medial meniscus were higher than in the lateral meniscus. The highest pre-stress in both the lateral and medial meniscus was found in the posterior regions, while the anterior regions experienced the lowest pre-stress. The obtained pre-stresses can be used for the accurate numerical analysis, the fabrication of artificial menisci, and the diagnosis of meniscal disease progression for human knee joints.