Preparation of experimental models of osseous nonunion

Deming XIAO; Zhongshi XU; Bowen LIN; Xiaohu LU; Dazhi YANG

ABSTRACT

BACKGROUND:

There is lack of an objective and standardized animal model for assessing the therapeutic effect of physical and medication treatment on bone defoct, the effectiveness of operation, as well as the role of bone substitute in the repairing of bone defects.

DESIGN:

Verified study on the experimental model of bone nonunion in rabbits

SETTING:

Department of Orthopaedics in Shenzhen people' s Hospital MATERIALSTwenty common grade pure New Zealand rabbits of either gender were selected with body mass of (2.5±0.5)kg,aged 6 to 8 months.

METHODS:

This experiment was carried out at the experimental animal center of Shenzhen people's Hospital between May and August 1999. 1.5cm bone segment (including periosteum)was cut off in the middle of forearm radius in 20 common grade pure NewZealand rabbits,the broken ends were covered with bone wax, 10 weeks later, the bone nonunion status was assessed by macropathological observation, pathohistological and X-ray examination.MAIN OUTCOME

MEASURES:

Observations on rabbit forearm radius defects by macropathological observation, pathohistological and X-ray examination.

RESULTS:

Twenty rabbits(40 side radius)were enrolled in this study and weeks later, bone defect region was found filled with fibrous cicatricial tissue without osseous connection ,bone wax was not absorbed, capitulum was ossified with medullary cavity blocked,a small amount of callus formed at both broken ends of fractural bone ,length of bone defect ranged from 0.8 to blocked under optical microscope,chondrocyte and osteocyte could be observed arranging disorderly and covered with fibrous membrane,defect reosseous connection could be detected at defect region at week 10,broken end was ossified and medullary cavity was blocked ,there was small amount of callus appeared at both broken ends displaying irregular shape.

CONCLUSION:

Bone nonunion experimental animal was successfully established on rabbits in this study, with pathological changes meeting the need of bone nonunion and displaying typical properties,which can be used as reliable and feasible experimental animal model.