OBJECTIVETo study the role of the synchronized springy lengthening apparatus for the tibia and calcaneal tendon designed by the author in preventing the clubfoot of secondary to the Ilizarov tibia lengthening.

METHODSBased on the Ilizarov tibia lengthening apparatus, a special synchronized springy lengthening apparatus for the tibia and calcaneal tendon was designed. The tibial was made of distal and proximal 2 rings respectively and 4 threaded rods, and the calcaneal was made of a half ring, 2 hinges and a threaded rod with spring. The half ring was fixed to the calcaneus by 2 crossed wires. The fracture tibia and fibula, ankle joint, talocalcaneal joint were attached to the apparatus. At the same time of tibia lengthening, the soft tissue was simultaneously stretched, the ankle joint could move, and the leg could bear weight. If the clubfoot angle was larger, the percutaneous fasciotomy of calcaneal tendon was performed; if the angle was less than 20 degrees, the pes deformities were corrected only by the stretch of calcaneal tendon.

RESULTSSeventy-seven patients' tibia were lengthened averagely 4.6 cm, with an average speed of 0.7 mm/d. The healing made tibia lengthened, and the index was 1.35 months/cm. There were not the secondary varus and valgus deformities and clubfoot in all the patients. The clubfoot with 100-400 angle of the 16 patients were corrected after tibia lengthening.

CONCLUSIONSThe new apparatus coincides with the biomechanical principle and can effectively prevent the secondary deformities of foot such as clubfoot, talipes varus and valgus after tibia lengthening procedure.