The effect of experimental epiphysiodesis on growth in length of the rabbit's tibia.

Since Stephen Hales (1769) demonstrated that the distance separating holes pierced through the leg and shin bone of a half-grown chick did not increase despite the increase in length of the whole leg, subsequent investigators, including Hunter (1837), Dubreuil (1913), Haas (1926), Payton (1932) and Lacroix (1949), have established that the epiphysial cartilage is the main site of growth in length of a long bone. The contribution which each epiphysis makes to the growth of bone has not received so much attention. Digby (1916) made some estimates based on a graphic projection of the nutrient canal to the centre of the shaft, and Payton (1932) determined the relative growth rates at the ends of long bones in madder-fed pigs. He showed that the rate of growth at each epiphysis diminished with age and that this was more rapid at the end that was to make the lesser contribution. Roche (1965) showed that the presence of a bony epiphysis was not essential for growth in length. He found that 20 to 30 per cent of elongation of the shafts of the first and second metacarpal bones and the metatarsal bones in white Australian children occurred at the non-epiphysial extremity. While it is clear that each epiphysis makes its own contribution to the length of the bone, it is not apparent whether the contribution of the epiphysis at one end is made irrespective of that at the other, or whether changes in the growth process of one epiphysis can influence that of others. That the latter possibility might be true was suggested by the report of Reidy, Lingley, Gall and Barr (1947). These workers investigated the effect of irradiation on epiphysial growth in the dog. They found that when the dose was directed to joints, as well as relative shortening of the bones there was also evidence of stimulation of growth at the untreated epiphyses of these bones, and they were unable to account for this. The possibility that this stimulation effect was due to the failure of the irradiated epiphysis to grow prompted the present investigation.