Data acquisition in a fracture stiffness evaluation

Two aspects of fracture stiffness in healing tibiae were examined. Static measurements were conducted on fractures managed by an external fixator, using strain gauge techniques. Dynamic analysis of measurements on the same patients using Fourier transforms shows good correlation with changes in stiffness at 8-10 weeks postfracture. The results from more than 30 patients show good correlation between static and dynamic techniques. Those patients who had uneventful, normal union tended to produce marked changes at 8-10 weeks (sometimes earlier). The instrumentation involved the use of microcomputers to collect and process signals from strain gauges and accelerometers, with clinical observations in each case extending over a period of about 20 min.<>