Abstract
Introduction: While the early period of distraction osteogenesis has been extensively investigated, there are no data describing the long-term morphology of the regenerate. Patients and Methods: We performed MRI scans to ten adults, seven of which had bone transport for an osseous defect while further three had lengthening for limb length discrepancy. Follow up ranged between 14 and 43 months (mean: 29 months) following the removal of the external fixator. The perimeter, cross sectional area, volume and the mean signal intensity was calculated from the obtained T1 weighted axial images. Values were compared with the contralateral tibia that acted as control. Results: All cases that had bone transport increased the volume of the tibia from 15.3% up to 50.8%. The regenerated segment was noted to have expanded significantly (p< 0.0001) in all cases. Mean signal intensity in the regenerate decreased in seven cases significantly (p< 0.0001) suggesting increase content of unhydrated tissue such as bone and collagen. The cross sectional surface of the transported segment was increased in all cases (p< 0.008), which associated increase in the signal intensity (p< 0.003). Finally in cases that underwent bone transport, the docking site was noted to be obstructed by unhydrated tissue. Conclusions: Contrary to previous claims, the post-distraction osteogenesis tibia is far from normal, consisting of areas with potentially different biomechanical properties. Recognition of these changes is essential not only for appropriate preoperative counselling but also for considering treatment modalities in case of a fracture.
Theses abstracts were prepared by Professor Dr. Frantz Langlais. Correspondence should be addressed to him at EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
