Femoral mineral density for bifocal distraction osteosynthesis in children and adolescents with congenital shortening of the femur

Mineral density (MD) of shortened femur was determined by the method of dichromatic absorptiometry in 15 patients. It turned out to be lower in comparison with intact bone. In the period of distraction the processes of mineral demineralization and accumulation in the proximal bone part were more active that those in the distal bone part. In the period of fixation mineralization of regenerate bones occurred identically. Demineralization in the middle part of the proximal regenerate bone was the highest on 30-th day of distraction, and in that of the distal regenerate bone - at the end of the third month. This is connected with the biomechanical details of bifocal distraction osteosynthesis of the femur. However, this feature didn't influence the formation periods of regenerate bones and their mechanical strength after device removal, that was performed at MD values of distraction regenerate bones amounting for 60-64% of the values of contralateral normal bone. MD value during congenitally shortened femur lengthening in children and adolescents demonstrated that the lengthening amount could be uniformly distributed at the proximal and distal levels. In all the parts of the distal regenerate bone MD didn't reach the initial level even in a year and a half after the device removal.