[Joint-sounds--clinical experience of the knee joint]

We are exploring sounds of the joint by means of a new analyzing system. These results on the knee joint are summarized and discussed in this paper. A knee joint is moved passively in some ranges for four seconds in unechonic chamber. A special microphone (B & K 4165) is kept to touch manually on the pre-patellar skin throughout the motion. These collected sounds are analysed with a narrow band spectrum analyzer (B & K 2031) and a computer (Tektronix 4051) and we measured the over all value every 500 Hz from 500 Hz to 5000 Hz. We obtained the sounds from the normal control and the osteoarthritic knee joints, and compared these two groups by the data of each frequency analysis. Total over all value were less than 80 dB in the normal knee. In the osteoarthritic knee, they increased in especially low frequency range.