At. Brooks et al., EFFECT OF AN ULTRASONIC DEVICE ON TEMPERATURES GENERATED IN BONE AND ON BONE-CEMENT STRUCTURE, The Journal of arthroplasty, 8(4), 1993, pp. 413-418
Cement removal during revision arthroplasty can be a tedious, time-con
suming process. The usual methods of removing cement include high-spee
d drills, chisels, saws and reamers, which are often associated with f
racture and/or perforation of the femoral shaft. Ultrasound has been u
sed in dentistry to remove plaque and in ophthalmology to remove catar
acts and is now applied to cement removal in orthopaedic surgery. Ther
e is little data available on the effect of ultrasound on temperatures
generated in bone and on its effects on the structure of bone-cement.
A cement mantle was constructed in the intramedullary canal in each o
f six 10 cm lengths of human cadaver femora. A temperature probe was t
hen inserted into predrilled holes and temperatures generated by the u
ltrasonic device were recorded under a variety of conditions. In addit
ion, a cement cylinder was microscopically evaluated after an ultrason
ic tool had been inserted. Temperatures generated by the ultrasonic to
ol in cadaver bone were no higher than previously reported temperature
s of 140-degrees-C generated by high-speed drills. Furthermore, temper
atures at the bone-cement interface never exceeded 60-degrees-C when s
aline irrigation was used in conjunction with the ultrasonic tools, an
d were below 40-degrees-C l minute after deactivation of the device. M
icroscopic examination shows that ultrasound produced local changes in
the structure of bone-cement converting it from a microscopically sph
erical interlocked material to one that appears homogeneous and granul
ar.