Osteoarthritis (OA) of the knee is a widespread disease caused by the articular cartilage damage, and its prevalence has become a severe public health problem worldwide, especially in the ageing society. Although X-ray, MRI, CT, etc. are commonly used to examine knee OA by inserting external high energy into the body, they do not provide dynamic information on knee joint integrity. In the present research, the acoustic emission (AE) technique has been applied in healthy individuals as well as OA patients in order to evaluate the knee integrity in dynamic analysis modes without inserting any external energy. Four groups of people, young, middle-aged, older, and OA patient have been participated in the present research, and significant results have been identified. It has been found that the degeneration of the articular cartilage progresses gradually with the increase of the age. The angular positions of knee damage are also evaluated by clarifying AE hits. The results are verified through clinical investigations by an orthopedic surgeon applying X-Ray and MRI techniques. The results of the present research demonstrate that the AE technique can be considered as a promising tool for the diagnosis of knee osteoarthritis.