Many of the elderly are predisposed to develop osteoarthritis (OA), although it is quite difficult to diagnose the early-grade OA even by latest imaging modalities. The purpose of this study is the clinical development of D-OCSA arthroscopic system. The visualization system using Arthroscopic Optical Coherence Tomography (OCT) probe which is essential as a diagnostic system has been developed. In addition, ex vivo animal experiments applying D-OCSA were also carried out using rabbit's OA cartilage caused by amputation of the rabbit's left knee ACL. As an experimental result of Arthroscopic OCT probe, it was confirmed that the construed system could provide morphologic diagnosis of cartilage, e.g. tide mark. D-OCSA can show the attenuation coefficient distribution of compressive strain rate during relaxation test, which could find superior increase in attenuation only for early OA cartilage. Therefore, it can be seen that there is a loss of visco-elastic properties as compared to normal cartilage. In summary, Arthroscopic D-OCSA system could be effective to assessments of the early OA as "Micro Mechanical Biopsy".