IN-VITRO EVALUATION OF BONDING OF THE CEMENT-METAL INTERFACE OF A TOTAL HIP FEMORAL COMPONENT USING ULTRASOUND

Debonding of the cement-metal interface of a cemented femoral componen t is one mechanism associated with loosening of total hip replacement. An ultrasonic pulse-echo technique was developed to determine, nondes tructively, the integrity of the cement-metal interface in vitro. The characteristics of the ultrasonic reflections of bonded and debonded i nterfaces were obtained by using a physical model that consisted of a flat slab of cement and a flat cobalt alloy plate with known condition s of bonded and debonded interfaces. The same model was used to establ ish that the ultrasonic technique could distinguish between two surfac es that were in direct apposition but not bonded and those that were a ctually bonded. This technique then was shown to be useful in nondestr uctively detecting bonded and debonded cement-metal interfaces of femo ral prostheses cemented into fiberglass femurs and femurs from human c adavera.