1. Arrest of growth at one proximal tibial epiphysis of young rabbits was obtained by stapling. 2. Radiopaque markers allowed the subsequent growth of both proximal and distal epiphyses of the experimental and contralateral tibiae and of both lower femoral epiphyses to be followed radiographically. 3. The reduction in the normal deceleration of growth rate at the distal epiphysis found after epiphysiodesis of the proximal epiphysis was again observed. 4. This change in growth rate was not encountered in the distal femoral epiphysis lying adjacent to the stapled tibial epiphysis. 5. Removal of the staples after the change in growth rate had become established at the distal tibial epiphysis was followed by a return to an approximately normal growth rate by both proximal and distal epiphyses. 6. It is concluded that a direct relationship exists between the additional growth at the uninjured epiphysis and the deficiency in growth obtained at the stapled epiphysis, and that this change in growth rate is limited to the experimental tibia.
1. Experimental epiphysiodesis was performed on either the upper or lower epiphysial cartilage of one tibia of young rabbits, the other tibia serving as a control. 2. Subsequent growth was observed at each epiphysis by radiography. 3. After both operations the normal deceleration of growth rate of the uninjured epiphysis on the experimental side was reduced and this epiphysis made a greater contribution than its control to the final length of the bone. 4. Serial sections of the injured epiphysis revealed that the arrest of growth was due to the formation of a narrow bony bridge between the epiphysial and metaphysial bone. 5. The additional growth of the uninjured epiphysis appeared to have a direct relationship to the deficiency of growth at the epiphysis that had been injured by operation. 6. The results may indicate the existence of a local system of growth control.
