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Abstract

The purpose was to study epiphyseal plate growth after microvascular transplantation to sites of different growth potential. The hypothesis was that the growth potential of an epiphyseal plate transplant is a function of the donor irrespective of the recipient site to which it is transplanted. Immature rabbits were used in an experiment that transplanted microsurgically revascularized second metatarsal epiphyseal plates. There were three experimental groups in which transplants were made to (i) sites of the same growth potential (orthotopic), (ii) sites of higher growth potential (proximal tibia), and (iii) sites of lower growth potential (third metacarpal). Control groups were nonoperated animals, animals with an anteromedial proximal tibial osteotomy, and nonoperated contralateral limbs of all experimental animals. Postoperative graft viability was checked with fluorochrome labeling. Postoperative growth was measured from serial standardized radiographs. Follow-up was for either 5 or 8 weeks. Animals were then killed, and epiphyseal plate specimens removed for histomorphometric analysis. Results showed that the total growth of experimental second metatarsal transplants was not statistically different (p > 0.05) in any recipient site. It was noted, however, that transplanted epiphyseal plates in all experimental groups grew at lower rates than nonoperated controls.

Catch-Up Growth: Cellular and Molecular Mechanisms

“…In both the growth plate and in non-skeletal organs, this decline in proliferation appears to be due to local, rather than systemic, mechanisms as evidenced by transplantation experiments between animals of different ages. When juvenile organs, including the growth plate (19;20), intestine (21;22), kidney (23), and heart (24) are transplanted into older recipients, these organs continue to grow rapidly, suggesting that growth deceleration is an intrinsic property of the organ.…”