Ossification and bone mineral deposition in three femurs and two tibias of four patients who underwent elongation by callotasis were examined by CT and DEXA to investigate bone formation by this method.
Sequential change of callus ossification in CT imaging was observed at three levels of the proximal, middle and distal area of elongation. By using DEXA, three quantitative indices for bone mineral deposition of elongated area such as BMC (bone mineral content), BMD (bone mineral density), %BMD (relative rate of BMD to that of the neighboring area) were measured and analysed against time.
In CT imaging, all materials showed a ring-shaped area of ossification around the periosteum, which increased in thickness against time although the thickness of the ring was not always circularly equal. The bone formation was observed always slower at middle part than at prosimal or dixtal part of elongation. All of BMC, BMD and %BMD revealed the time-dependent gradual increase during and after the neutralization stage in callotasis. There was a correlation between their values and the ossification; the better callus ossification provided the higher values in every indexes measured by DEXA. It is suggested, in conclusion, that CT imaging and DEXA are potentially useful for evaluating the degree of the bone formation in callotasis.
