| Objective: With the development of modern society industry and traffic, the incidence of distal femur fracture multiple injury is higher, the tendency is rising. Distal femur fracture are common , representing 4%～7% of the all femur fracture, 0.4% of the all fracture dislocation. Distal femur C3 Type fracture was intra-articular fracture. The fracture were comminuted with high energy, the degree of injury was heavy. Conservative treatment such as skeletal traction not only spend long time , but also usually leaded to some complications, such as malunion, stiff joint anchylosis and pain, et al in the comminuted fracture of the femoral, and also the operation may be quite difficult due to the severe comminuted fracture,bone defect and skin injury. The operation were not satisfactory because they cannot got anatomical reduction. Fractures of the distal femur can often present a significant challenge to the orthopedic surgeon. There are not connected reports about the different of adoption of condylar buttress single- plate, double- plate and buttress single- plate associated with autografting of fibula in biomechanics. The purpose of this study was to provide theoretical basis on selecting optimal fixing method after distal femur internal fixator according to biomechanics tests comparison by condylar buttress single-plate, double-plate and buttress single-plate associated with autografting of fibula. It provided the biomechanical evidence and set up theoretical base for clinical operation. Compared control group with treatment group, explored its therapeutic effect and the incidence of complication for new thought and method.Methods:1 The biomechanics study on three internal fixation for the treatment of distal femur C3 Type fractureNine embalmed femur, an osteotomy which was perpendicular to the middle-femur. The mean age was 37 years, range 30～55 years, and there were all male. All of these specimens were visually examined and then X-rayed to exclude the presence of femur or soft tissue disease. All muscles and connective tisstues, including the hip capsule were dissected. The saw cut bone cortex from femur intercondylar fossa to lateral epicondyle and medial epicondyler,cut 1.5cm wedge fracture on the medial epicondyle 5cm. According to the AO classification, made a distal femur C3 Type fracture. Reduce the fracture anatomical in the eyesight, keep the Kirschner temporary fixation . The fractures have been fixed by using condylar buttress single- plate , double- plate and buttress single-plate associated with autografting of fibula . Using the mixed denture base resin embedment the fixationed specimens on superior extremity. A platform was made on distal femur with mixed denture base resin. The platform was paralleled with the horizontal surface in standing and sitting neutral position. This repaired biomechanical study was finished by a biomechanical test machine (Model:CSS-44020,changchun,China). Each femur was put on the jig. Biomechanical tests of bending, and compression were performed. Based on the data of the stress change of load and bias, the conclusion was drown. The ultimate loading was recorded when the fixed femur was loaded to failure. The experimental data was analyzed by the one way ANOVA in SPSS12.0 statistic software. The statistical significance for the test was set at P<0.05.2 The clinical applications on three internal fixation for the treatment of distal femur C3 Type fracture From March 2005 to August 2006, 44 patients of distal femur fracture were treated by external fixator. All of the fracture were classified according to AO classification. The patients were randomly divided into two groups: control group (male20 , female 4),the mean age of control group was 36 years, range 22~55 years. Treatment group (male 15,female 5) , the mean age of treatment group was 35 years , range 21~57 years. All patients were scanned by X-ray before operation. The patients complicated with severe injuries were treated with second operation internal fixation operation . All patients were followed up for 6 months to 14 months. The clinical information was collected and subjected to statistical analysis. Based on the dated, the conclusion was drew. Results:1 The biomechanics study tests showed that it was the best fixing of the distal femur fracture by double- plate, single-plate was the most remarkable variation and the less in single-plate associated with autografting of fibula. In the vertical compression test, the average displacement was 0.54±0.21mm, 0.61±0.24mm and 0.96±0.35mm. It compared with fixing of the single- plate, the distal femur stability was better by using double-plate and single-plate associated with autografting of fibula. In the three-point bending test the displacement was 4mm, the average pressure was 74.58±11.28N ,88.47±13.73N and 127.84±16.35N. In the ultimate displacement test, there is not statistical difference among them.2 The clinical applications on three internal fixation for the treatment of distal femur C3 Type fracture。In clinical practice, it had better therapeutic effect, lower complications and higher satisfaction degree of the patients. Application of chi square test in the groups, it was a significant difference(P<0.05).Conclusion:1 Buttress plate associated with autografting of fibula for the fixation of distal femoral C3 type fracture has more excellents results in biomechanical tests. Bending and compression tests showed that they were much stronger (P<0.05) than the single-plating group in anti-bending and anti- compression.2 Buttress plate associated with autografting of fibula for the treatment of distal femoral C3 type fracture can provide more stable fixation to the bone and earlier functional exercises can be achieved.This method can solve the difficulties of reduction, stress line restoration, bone defect repairing, rigid plating, early knee functional exercising and fracture healing. The biomechanical properties of double- plate are better than single-plate associated with autografting of fibula, but single-plate associated with autografting of fibula faster healing, less bleeding , lower complications, it played a medial buttress role in and higher satisfaction degree of the patients. It meets the requirement of the biological fixation for fracture. The methods could protect knee varus, knee valgul and other complications, advanced fracture healing. It is an effective way for the treatment of this kind of fractures. |
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