Fuzzy RASP determination by 1kHz ultrasonic probe for total hip arthroplasty

This paper describes an effective system of selecting most suitable rasp for the patients. We suggest the ultrasonic system with a single ultrasonic probe. Firstly, we make a knock to the upper point of the rasp inserted with a hammer which has the trigger signals. We detected the acoustic signals with the knocking signals. An ultrasonic probe is fixed in the upper side of the rasp with a built-in magnet. A personal computer got the acoustic data. In the surgery, the surgeon tries to adapt for the patient from the small size rasp to the larger size rasp in turn. There is a correlation between the degree of tightening and the attenuation time of acoustic signal for the knocked sound by a hammer when inserting the rasp. The higher tightened degree implies shorter attenuation period. At the present time, the surgeon´s experience chooses the suitable rasp. Therefore, we suggest the rasp determination system which selects the suitable rasp by fuzzy inference which dynamically corresponds for each patient. As the result, we successfully determined the suitable rasp in comparison to the results obtained from the practical surgery. We could indicate the indexes in order to judge how degree the rasp fits in the clinical treatment.