Free microvascular epiphyseal-plate transplantation. An experimental study in dogs.

To evaluate the feasibility of transplanting vascularized epiphyseal plates while maintaining normal growth in the recipient site, twenty-two puppies from known, large breeds were divided into one control and three experimental groups of four animals each and one long-term group of six animals. The control group underwent insertion of a radiopaque marker in the fibular metaphysis bilaterally, and, in addition, a fibular osteotomy was performed on one side. In the experimental groups, a fibular switch was carried out, selecting one fibula as a vascularized graft and the other as a non-vascularized graft. Both the controls and the experimental groups were evaluated using serial roentgenograms, histological examination, fluorescent bone-labeling, and microangiography. One week, six weeks, three months, and seven months postoperatively, animals from each group were killed. Continuous growth was observed in the vascularized epiphyseal transplants and in the controls, with no statistical difference noted, whereas the non-vascularized transplants exhibited considerably less or no growth. Vascularized transplants demonstrated an average 21.2-millimeter increase in length while non-vascularized transplants showed a 6.6-millimeter increase. Histological examination, fluorochrome bone-labeling, and microangiography confirmed the continued viability of the vascularized epiphyseal transplants in contrast to the non-vascularized transplants.