Jr. Dickens et al., AN ULTRASONIC-ATTENUATION PARAMETER FOR INVESTIGATING THE HOLDING POWER OF NON-THREADED FIXATION PINS IN CANINE FEMUR (IN-VITRO), Ultrasonics, 32(1), 1994, pp. 65-70
Citations number
31
Categorie Soggetti
Acoustics,"Radiology,Nuclear Medicine & Medical Imaging
External skeletal fixation (ESF) is a widely used method of fracture t
reatment but often produces medical complications in the patient. The
most serious complication, pin loosening, may lead to pain, poor limb
usage, pin tract infection, fracture instability and non-union. Studie
s of pin loosening are based primarily on pin extraction force measure
ments, which are destructive in nature. This paper will introduce a me
thod for estimating the extraction force of non-threaded fixation pins
based on three related parameters obtained from an ultrasonic pulse i
ntroduced into the pin. The ultrasonic test takes advantage of the inh
erent acoustic absorption across the bone-pin interface. A strong inte
rlock between bone and pin results in increased transmission of ultras
ound across the bone-pin interface. This is manifested as heavy signal
attenuation, whereas a poor interlock results in considerably less at
tenuation. The parameters proposed in this paper are intended to quant
ify attenuation resulting from bone-pin interface interactions. One pr
obe-parameter combination in particular showed considerable sensitivit
y to the conditions of the bone-pin interface (R(2)=0.79). Further res
earch is suggested and may lead to an operational process for non-inva
sively evaluating pin security.