胫骨与跟腱同步弹性延长器的设计与临床应用

目的　探讨胫骨与跟腱同步延长器在预防Ilizarov胫骨延长并发马蹄足中的作用。方法　在Ilizarov环形胫骨延长器的基础上设计了新型胫骨与跟腱同步延长器。胫骨延长器由远近各两个钢环和 4个延长杆组成 ;跟腱牵伸器由 1个半环、两侧的铰链关节和一个套有弹簧牵伸杆组成 ,并与胫骨延长器远端的钢环连接在一起。跟腱牵伸器的半环以两根交叉钢针固定在跟骨上 ,胫腓骨截骨的上下端、踝关节、跟距关节被固定在一个延长器上 ,使胫骨与小腿软组织包括跟腱在延长过程中获得同步相同张力的牵伸 ,踝关节尚能做主被动伸屈运动 ,患肢在延长过程中可以负重。如术前有较重的垂足畸形 ,术中可将跟腱施行闭合切开滑行延长 ;若术前马蹄畸形 <2 0° ,仅通过跟腱牵伸即可矫正。应用胫骨与跟腱弹性同步延长器治疗下肢不等长患者 77例。结果　 77例小腿平均延长 4 6cm ,平均延长速度 0 7mm/d ,延长骨的骨愈合指数 1 35个月 /cm ,所有患者皆未出现足下垂、内翻、外翻等畸形。 16例患者术前合并 10°～ 4 5°的足下垂畸形 ,胫骨延长后亦获同期矫正。结论　胫骨与跟腱同步延长器构型符合生物力学原理 ,可有效地解决胫骨延长术后常见的足下垂、内翻、外翻等并发症。

The design and application of synchronized springy lengthening apparatus for the tibia and tendo calcaneus

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.