BONE HEALING FOLLOWING 2 METHODS OF NONRIGID TIBIAL OSTEOTOMY REPAIR IN THE DOG

Bone healing was assessed after stabilisation of transverse tibial ost eotomies in adult Beagles (n = 6) with intramedullary pins, in conjunc tion with modified Mennen clamp-on plates to counteract rotation. Post -operative return to full limb function was compared to that after use of a two-pin, uniplanar (Type I) external skeletal fixator and an int ramedullary pin combination (n = 6). Additional external splinting was not used. The dogs were graded weekly after exercise, according to a functional performance grading scale. All of the clamp-on plates were well tolerated. Bony periosteal callus incorporated the crimp arms and the mean time required for full limb function was 7 weeks. The clinic al performance of the dogs, with the external skeletal fixators and in tramedullary pins, was consistently lower during the initial 4 weeks. Soft tissue swellings with pin-tract drainage occurred, but resolved f ollowing removal of the transcortical fixation pins. These dogs return ed to full limb function with bony bridging callus after 8 to 9 weeks. Quantitative assessment of the bone activity, using sequential scinti graphy at weekly intervals, suggested consolidation of the callus 6 we eks after the operation for the clamp-on plate and pin combination, an d at 7 weeks for the external skeletal fixator and pin combination.