Long-term follow-up of vascularized bone grafts for the reconstruction of tibial nonunion: evaluation with computed tomographic scanning.

Ten cases of reconstruction of the tibia with vascularized bone grafts were evaluated by computed tomographic (CT) scanning. In all cases the grafts were placed because of pseudarthrosis. The patients ranged in age from 20 to 64 years. The duration of follow-up was 1-9 years. In six cases fibular grafts were used to bridge the defect and in four cases iliac crest grafts were used. No additional bone grafts were placed after the initial operation. The pseudarthroses were classified into three types: type N--no bony defect (4 cases); type P--partial bony defect (3 cases); and type C--complete segmental bone loss (3 cases). Our evaluation showed that the grafts used to treat the type N and type P pseudarthroses were the same shape and size as at the time of placement. The grafts used to treat the type C pseudarthroses were hypertrophied, although the medullary canal of the graft remained the same size as at the time of placement. Hypertrophy was a result of an extraperiosteal reaction. The fibular grafts were square rather than triangular in cross section. It was concluded that mechanical loading is important in promoting hypertrophy of the graft.