OBJECTIVETo compare the effects of cyclosporine-impregnated bone allograft (CAB) and freeze-dried bone allograft (FDAB) in repairing radial defects in rabbits.

METHODSThirty New Zealand white rabbits were randomized into bone graft donor group, experimental group, and control group (n=10). The bilateral ilia of the donor rabbits were dissected to prepare CAB and FDAB. In the other 20 rabbits, a 10-mm long segmental osteoperiosteal defect was induced in the right radius and repaired with CAB (experimental group) or with FDAB (control group). At postoperative weeks 4 and 12, 5 rabbits from each group were sacrificed to evaluate the bone healing by radiographic, general and histological observations.

RESULTSFour weeks after the operation, the rabbits in the experimental group showed significantly higher X-ray scores (P=0.001) with greater amount of new bone and better incorporation of the allograft and autogenous bone than those in the control group. At 12 weeks, the X-ray scores were still significantly higher in the experimental group (P=0.002), which also showed better bone remodeling than the control group.

CONCLUSIONCAB is superior to FDAB for repairing radial defects in rabbits, but the potential involvement of local immunoreaction in this difference awaits further investigation.