THE NEURONAL REGULATION OF FRACTURE-HEALING - EFFECTS OF SCIATIC-NERVE RESECTION IN RAT TIBIA

The effect of sciatic nerve resection on tibial fracture healing was s tudied in rats 25 days post-trauma. To prevent differences in loading between sham-operated and nerve-resected animals the fractured limbs w ere cast-immobilized. On radiograms 8 of 11 fractures in the sham-oper ated animals showed very little callus formation in contrast to only 1 of 8 fractures in the group with nerve resection. Measured by single- photon absorptiometry, animals with sciatic nerve resection had a high er bone mineral content than the sham-operated animals. However, the m echanical strength in three-point cantilever bending was not better in the nerve-resected rats, implying a defective organization of the lar ge callus. These results suggest neural regulation plays a role in the type of fracture healing, primary or secondary, and in the amount and quality of the callus.