Epiphyseal plate transplantation between sites of different growth potential

The purpose was to study epiphyseal plate growth after microvascular transp lantation to sites of different growth potential. The hypothesis was that t he growth potential of an epiphyseal plate transplant is a function of the donor irrespective of the recipient site to which it is transplanted. Immat ure rabbits were used in an experiment that transplanted microsurgically re vascularized second metatarsal epiphyseal plates. There were three experime ntal groups in which transplants were made to (i) sites of the same growth potential (orthotopic), (ii) sites of higher growth potential (proximal tib ia), and (iii) sites of lower growth potential (third metacarpal). Control groups were nonoperated animals, animals with an anteromedial proximal tibi al osteotomy, and nonoperated contralateral limbs of all experimental anima ls. Postoperative graft viability was checked with fluorochrome labeling. P ostoperative growth was measured from serial standardized radiographs. Foll ow-up was for either 5 or 8 weeks. Animals were then killed, and epiphyseal plate specimens removed for histomorphometric analysis. Results showed tha t the total growth of experimental second metatarsal transplants was not st atistically different (p > 0.05) in any recipient site. It was noted, howev er, that transplanted epiphyseal plates in all experimental groups grew at lower rates than nonoperated controls.