Clinical application of the improved llizarov's external circular fixator in correction of lower limb deformity

Abstract

Objective To report a self-improved llizarov's external circular fixator which can be used for correction of lower limb deformities.Methods The Ilizarov's external circular fixator was improved according to the specific requirements for correction and reconstruction of lower limb deformities in Chinese patients and manipulative convenience for the doctor.We tried to improve the complex,heavy and clumsy Ilizarov's external circular fixator by designing a set of accessories,including spring traction apparatus,threaded half-pins and minimally invasive osteotomy tubular tools.The whole combined orthotic device could be assembled individually before operation according to the specific characteristics of the lower limb deformity to be treated.From January 2004 through December 2010,the improved fixator was used to treat 146 patients,95males and 51 females,aged from 3.6 to 61.0 years ( average,33.4 years).There were 18 cases of hip deformity,49 cases of knee flexion deformity,10 cases of valgus of the distal femur,46 cases of varus of the proximal tibia,and 23 cases of tibial defect or nonunion combined with other complex deformities.Results The patients were followed up from 8 to 46 months (average,28.6 months).Lower limb deformities were corrected,the weight transmission line of the whole lower extremity was restored and walking function was significantly improved in 139 patients.One patient experienced displacement of the distal osteotomized bone which was corrected by adjusting the external fixator.Two patients had residual varus of 10 to 15 degrees after proximal tibial osteotomy.Three patients had malfunction in knee flexion after bone lengthening.Four patients suffered from pin tract infection.By the Harris hip scoring,the mean preoperative score (36.91 ± 3.14) was improved to (86.25±2.26)pestoperatively.The knee flexion deformity was completely corrected in all the 49 patients.The tibial nonunion was cured by new bone formation and lower limb function mostly restored in all the 23patients.Conclusions The improved orthotic device not only retains principal functions of the Ifizarov circular external flxator but also satisfies needs for correcting various deformities,repairing disabilities and reconstructing functions of the lower limb in Chinese patients.It deserves popularization in clinic. Key words: Lower extremity; External fixators; Bone remodeling; Iizarov technique