Bone remodeling in limb lengthening: quantitative and qualitative evaluation

Purpose. To study bone remodeling processes during limb lengthening at the stages of treatment and in the long-term period. Materials and Methods. We examined 105 patients with limb shortening and deformities of different etiology at different stages of lengthening using computed tomography technique in order to study remodeling processes not only in the newly formed bone but in the adjacent parts of maternal bone as well. Results. The obtained results demonstrated that during device limb distraction and fixation the cortical plate in all groups of patients was of heterogenic structure with presenting resorption zones of different size, shape and density shortly after the Ilizarov fixator demounting. The values of 300-350 HU were critical. The cortical plate local density in osteon layer was maximal. Bone organotypic reorganization after lengthening completed after 1-3 years depending on disease etiology and lengthening amount. As MSCT data demonstrated, bone remodeling in the zone of distraction regenerated bone occurred in several stages beginning with resorption of longitudinally oriented bone trabeculae, in the direction from maternal bone to the regenerated bone center. In the long-term period the medullary canal in this zone had an even surface on the part of endosteum. Conclusion. The obtained results allowed to follow the dynamics of bone remodeling in the zone of lengthening for identifying the quality of newly formed bone, as well as to show the potentiality of intravital determining stages of remodeling which occurred similar to that of bone growth using current techniques of radiation diagnosis.