Healing of experimental fractures in the denervated limbs of the rat.

The effects of denervation on healing of experimental fractures of the tibia after sciatic nerve section or spinal cord transsection or both were studied in rats. In addition to normal weight-bearing controls, non-weight-bearing controls were prepared by means of experimental hip luxations. The healing of fractures was monitored by tensile strength measurements, and by X-ray studies up to two months. The tensile strengths of the fractures with peripheral nerve lesion or with spinal cord trauma were significantly higher than those of the respective weight-bearing or non-weight-bearing control fractures at the early phase of healing. Osseous union of denervated fractures was radiographically evident earlier or at least at the same time as in the controls. Denervation, however, caused irregularities in the radiopacity and increased the length of fracture callus. These results confirm the clinical observations on enhanced healing of fractures in extremities of patients with spinal cord trauma.