Narrow Results

We investigated whether controlled dynamization enhanced regenerate bone healing in callotasis of the tibia in 12 adult mongrel dogs. An average of 2 cm (≒ 10%) lengthening was obtained. The left hindlimb was allowed dynamization of 1 mm, 2 mm, and 3 mm in magnitude when 1 cm (≒ 5%) of lengthening was achieved, whereas the right hindlimb was not dynamized and served as a control. Bone mineral density (BMD) of the regenerate bone was measured periodically until nine weeks after the end of distraction. After sacrifice, uniaxial compression testing was performed. Relative BMD ratio and mechanical properties of the regenerate bone were significantly higher in the dynamization group than in the nondynamization group; no significant difference was found among dynamization subgroups, however. We conclude that 1 mm to 3 mm of elastic dynamization accelerates regenerate bone healing in callotasis of the canine tibia.

Distraction osteogenesis refers to bone regeneration under tensile stress with axial rhythmic distraction after osteotomy. It is applied on limb lengthening to treat dwarfism, bone transport, correction of limb deformity, and arthrodiastasis. However, clinical complications have been reported, including delayed consolidation, pin tract infection, and muscle wasting. It is essential to generate animal models for investigating the enhancement of bone formation, the design of bone lengthening fixation, and the distraction protocol. This chapter describes and discusses a rabbit tibial distraction osteogenesis model established by the authors for various applications.