Effects of alternating current electrical stimulation on lengthening callus

Limb lengthening by the callotasis method has been clinically applied to patients who suffered from limb length inequality, micromelia, angular deformation and partial bone defect on long bones. However, this technique was time consuming and led to various complications, such as infection at the pin insertion sites, limitation of the range of motion in adjacent joints, muscular weakness and peripheral neuroparalysis. This study was undertaken to investigate whether alternating current electric (AC) stimulation could shorten the maturation period during callotasis. The tibiae of 20 immature male Japanese white rabbits were osteotomized and fixed with external lengthener (Orthofix M100; Orthofix Srl, Bussolengo, Italy). The experimental schedule lasted 5 weeks consisting of 1 week for the latency period, 2 weeks for distraction and 2 weeks for maturation. Twenty rabbits were equally divided into two groups: the control group and the electrical stimulation (ES) group. The control group was not stimulated with an AC stimulator. The ES group was stimulated for 5 weeks just after osteotomy. The obtained results revealed radiologically, electrophysiologically and histologically that AC stimulation accelerated the maturation of lengthened callus and that it could shorten the time course of callus lengthening.