Attempted limb lengthening by physeal distraction. Continuous monitoring of an applied force in immature rabbits.

The effectiveness of physeal distraction in stimulating bone growth in animals was investigated by force applied to the distal femoral growth plate of immature rabbits. The system was continuously monitored to detect physeal separation. A distraction of 0.25 mm every 12 hours led to physeal separation in five animals. One animal given a 6-kg force and two of seven given a 4-kg force showed physeal separation. All four rabbits given a 2-kg force and five of seven given a 4-kg force did not show a greater increase in length than the control femurs. Bone growth was not stimulated by physeal distraction. Any increase in length of more than the normal growth is attributable to physeal separation.