| ObjectiveIt is a basical and clinical research for the lower limb trauma using Ilizarov method. The basical research:(1) To establish rabbit models of tibia diaphyseal lengthening. To observe and analysis the blood circulation and the new callus formation at the osteotomy site with X-ray and color doppler ultrasound. To compare the advantages and disadvantages between the two detective methods.(2) To observe the degree and rule of injury in the articular cartilage of the rabbit knee joint through morphological observation, MRI, histological staining and biomechanical testing.(3) The clinical research is mainly the practice about3kinds of diseases in the lower limb trauma applying Ilizarov method. Summarize the indication and applying value of this method in the clinical work.MethodsThe basic study:The rabbit models were established under general anaesthesia by means of the upper third of tibia osteotomy and slow traction for lengthening. Lengthening was commenced traction7days after surgery at a rate of lmm twice a day. Lengthening was continued to increase30%over initial bone length and stopped to be mineralized for5weeks. With the color doppler ultrasound to observe and analyse the blood circulation and the new callus formation at the osteotomy site at different stages during limb lengthening, we compare the outcome between ultrasound and X-ray. In addition, we need to examine the active range of the knee and ankle joint before and after surgery. With the X-ray to measure the length and diameter of the tibia before surgery, we make sure the length needed to lengthen and the diameter of the half pins. Also, we could observe the length and the new callus at the lengthening area and the limb alignment with the X-ray after surgery. The knee articular cartilage of different groups was harvested. To observe the injury level of cartilage using topographic observing and MRI detection. To know the cartilage changes with HE staining. The antiforce ability of articular cartilage under the biomechanical testing. All the data was analysed by statistic method.Clinical study:3kinds of diseases in the lower limb trauma were treated with Ilizarov method. They are the fresh fractures, the chronic fractures and the post-traumatic deformity. The indications and clinical applying values of this method were discussed by evaluating16typical cases.Results1. The animal model established successfully; the more the lengthening, the more obstacle of dorsiflexion of the ankle and extension of the knee; After5weeks consolidation, the function of the joints was improved, but was not recovered to be normal; X-ray observation:when the limb was lengthened to a increase of10%there was no clear evidence of new bone formation within the traction sites. When the limb was lengthened to20%, small amount callus at the osteotomy site could be seen. When lengthened up to30%, there is much more callus at the lengthening area, and the cortical bone appeared at both ends. With the extension of the consolidation, the cortical bone of the both ends get in touch with each other and the medullary cavity appeared. After7weeks consolidation, the callus union and with a good alignment of the limb; Ultrasound:In the early stage, the amount of the micrangium and the rate of blood flow increased and then decreased gradually. After1week, we could see some speckled echogenic at the traction site that means new bone has formed. When the limb is lengthened up to30%, the ultrasound islands coalesce and the accuracy of gap measurement is reduced. Serial longitudinal ultrasound scans showed the traction gap as an echolucent window. New bone appeared as echogenic islands which became aligned longitudinally and progressively increased to fill the window. From the transverse ultrasound images, the proximal and distal segments of bone were seen as hyper-reflecting lines. At the site of the traction gap, these lines broke up into speckled echogenic areas corresponding to the presence of immature new bone.2. The same results about articulate cartilage were obtained from4aspects:the more the lengthening level, the more serious the cartilage changes. The data material of lower lengthening groups is similar with that of control group. The serious pathological changes of articular cartilage were observed from lengthening30%group and consolidation5weeks group. Such as the signal increased beneath the cartilage from MRI, meaning the matrix beneath cartilage has hyperplasia and calcify. The color of the articular cartilage is pale with poor luster; Obviously derangement, disorder layers, scattered degeneration cells, disappeared nuclear were found by histological staining. The antiforce ability of the articular cartilage has decreased obviously under the biomechanical testing.3. Clinical part:all the patients were follow-up and had satisfied results.Conclusion1. Dopplar ultrasound can discover the new bone callus formation at early stage of limb lengthening. The time is earlier than X-ray. We can forecast the outcome and change the rate of lengthening through the ultrasound image. In brief, the two ways have their own advantages and disadvantages. If the two methods were combined together, they will give us much more accurate information during limb lengthening.2. The more the lengthening level, the more serious the cartilage changes. The damage level of the cartilage can be observed by MRI. The data coming from the biomechanical testing is similar with that of other detecting methods. So the relation with the limb lengthening and the injury of articular cartilage is necessery.3. Ilizarov method is the effective way for all sorts of fresh fractures, chronic fractures, infected fractures with soft tissue defects, it is effective for the less invasive correction of the post traumatic deformity of the lower limb. Ilizarov frame has good biomechanical character. For fresh fracture, don’t need bone grafting and without incision, full weight bearing can begun early. The gradual correction applying Ilizarov method has more advantages and less injury than acute correction. |
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