CORRELATION BETWEEN ULTRASOUND IMAGING AND MECHANICAL AND PHYSICAL-PROPERTIES OF LENGTHENED BONE - AN EXPERIMENTAL-STUDY IN A CANINE MODEL

The right tibias of 16 adult mongrel dogs were lengthened 2.5 cm using a uniplanar lengthening device (Orthofix). After the animals were kil led in groups of 4 at 3, 6, 9, and 12 weeks postlengthening, ultrasoun d imaging and mechanical and physical testing was performed. There was a direct relationship between the percentage of intact cortices on ul trasound imaging and the mechanical and physical properties of lengthe ned bone. However, once 80-90% of all the cortices regained their cont inuity, the strength of the lengthened bone was only 50-60% that of th e control. Ultrasound imaging, therefore, may be useful in predicting the mechanical and physical properties of lengthened bone in the early phases of limb lengthening. Once all the cortices become continuous, however, another method for assessment of the mechanical properties of lengthened bone should be used.