微細構造を考慮した力学モデルに基づ＜軟骨の変性評価

摘要

The degeneration of articular cartilage impairs primal functions such as load transfer and distribution, and consequently, harms activities of daily life seriously. Evaluation of the mechanical property will be of help in clinical diagnosis of the degenerative disease of cartilage. Articular cartilage shows the depth-dependent laminar structure. The tissue composition and its microstructure are involved in the cartilage degeneration. Thus, the establishment of an evaluation method considering its microstructure is favorable for the accurate evaluation of the mechanical property. To examine the depth-dependent mechanical property that is difficult to be estimated by experiment, this study proposes a model-based evaluation method of the cartilage material property by means of the mechanical model reproducing tissue microstructure properties. Using the present model, the mechanical properties of normal and enzymatically degenerated cartilage of the bovine femoral heads were identified, and the degeneration in the medial (load-supporting) and the lateral (non load-supporting) regions were investigated. The elastic modulus was decreased by collagenase-treatment at both regions throughout all layers of cartilage. The mobility of interstitial fluid in tissue was increased by the treatment at both regions.