title: [The design and application of synchronized springy lengthening apparatus for the tibia and tendo calcaneus].
abstract: OBJECTIVE
  To 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.
  
  
  METHODS
  Based 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.
  
  
  RESULTS
  Seventy-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.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Department of Orthopaedics, Orthopaedic Hospital of Chaoyang, Beijing 100024, China.
authors.forename: Si-he
authors.initials: SH
authors.lastname: Qin
authors.forename: He-tao
authors.initials: HT
authors.lastname: Xia
authors.forename: Ai-min
authors.initials: AM
authors.lastname: Peng
authors.forename: Jian-wen
authors.initials: JW
authors.lastname: Chen
authors.forename: Xue-jian
authors.initials: XJ
authors.lastname: Zheng
authors.forename: Xue-hua
authors.initials: XH
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D001852:Bone Lengthening / Q000295:instrumentation* / Q000379:methods; D002648:Child; D004867:Equipment Design; D005260:Female; D006801:Humans; D007870:Leg Length Inequality / Q000601:surgery*; D008297:Male; D016896:Treatment Outcome