Bone defect healing in the absence and presence of a plastic catheter: an experimental study in the rabbit

The healing pattern of small, round, cortical defects, drilled in the upper tibial diaphysis of rabbits, was studied histologically and histomorphometrically. Group I rabbits were not further handled. In groups II and III animals, a polyethylene catheter was introduced into the medullary cavity by way of a second cortical hole and driven forward until its tip was close to the first cortical defect. Group II rabbits were not further handled. The cortical defect of group III animals was irradiated from a diode source via a fiber optic cable in the catheter. Assessment of the osseous healing of the cortical defects revealed neither qualitatively nor quantitatively significant differences among the three groups. The morphological observations imply that the presence of an intramedullary biocompatible catheter, which abuts on a cortical defect, does not hinder the normal progression of osseous bridging of the gap.