Swan-shaped bone fixation device made of Ni-Ti shape memory alloy for treating humeral fracture in rabbits.

Kang QL, Zhang CC, Gao TC, Xu SG, Ren K.

Department of Orthopedics, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.

OBJECTIVE: To establish the animal model for treating humeral fracture with swan-shaped bone fixation device made of Ni-Ti shape memory alloy.

METHODS: Models of humeral fractures was established in 30 rabbits and on one side the fracture was fixed with the Ni-Ti shape memory alloy device (SMC side) and on the other with 4-hole dynamic compression plate (DCP side). Anteroposterior radiograph of both humeri were taken at the time points of 2, 4, 8, and 12 weeks respectively after operation.

RESULTS: All the rabbits survived the experiment and their forelimbs bore obviously less weight than hindlimb. In SMC side, the humeral fracture healed without either osteoporosis or external callus. The fracture healing in DCP side gave rise to obvious external callus formation, and the healing process took significantly longer time than in SMC group.

CONCLUSION: The humerus of rabbit is similar to human humerus in view of their anatomic morphology and biomechanical properties, therefore rabbit humeral fracture models can be ideal for exploring the mechanism of fracture healing induced by the alloy device.