Regeneration of the growth plate.

The occurrence of growth plate regeneration has been doubted. However, in 5 different series of experiments reported between 1950 and 1986 regeneration of injured parts of growth plates in long bones of rabbits and pigs could be demonstrated. The 1st series implied partial X-ray injury of growth plates in rabbits aged 3-6 weeks. The 2nd series implied autotransplantation of the head of the fibula in rabbits aged 10-21 days. The 3rd, 4th and 5th series implied transplantation of autologous fat grafts into provoked defects of growth plates in rabbits and pigs. The findings show that regeneration of a growth plate occurs when a part of it is injured in such a manner that a bone bridge is not formed between the epiphysis and the metaphysis. Regeneration of a plate is much faster in relation to the growth in length of the bone in the rabbit than in the pig. The 1st and 2nd series suggest that regeneration takes place by interstitial proliferation of cells from the germinal layer of the uninjured parts of the plate. Signs of partial regeneration of growth plates have been seen in radiographs after operation for partial closure of growth plates in children.