A HISTOMORPHOMETRIC STUDY OF RABBIT TIBIOFIBULAR BONES AFTER RIGID INTRAMEDULLARY NAILING

The effects of rigid intramedullary nailing on cortical bone structure were studied in osteotomized and non-osteotomized rabbit tibiofibular bone at time intervals ranging from three to 24 weeks postoperatively . Histological specimens were analysed morphometrically observing chan ges in cortical bone and the medullary cavity in transverse sections d istal to the tibiofibular junction. Throughout the series, when compar ed to intact control bones computerized planimetry revealed significan t differences only in the osteotomized bones. At 24 weeks, the area, o f whole cortical bone was less and the area of the medullary cavity gr eater in the osteotomized bones than in respective control bones. The reason for these changes seemed to be a profound resorption of subendo steal bone. The amount of cortical osteoporosis was slight, but a stea dy increase could be seen towards the end of the experiment The result s suggest that the morphological changes in cortical bone detected in the present study mostly depend on the operative trauma and not so muc h on the protection from stress provided by the rigid intramedullary n ail.