RESUMO
BACKGROUND: The proximal femur anti-rotation intramedullary nail is an ideal internal fixation method for the treatment of intertrochanteric fractures, but there is still a 6% to 21% failure rate of internal fixation. Tip-apex distance is considered as an important cause of postoperative proximal femur anti-rotation intramedullary nail failure. Tip-apex distance is the sum of the distance from the tip of lag screw to the vertex of femoral head measured on anteroposterior and lateral X-ray films. Most scholars now believe that the tip-apex distance of head pulp nail ≤ 25 mm has a good prognosis, but there is still a lot of controversy. OBJECTIVE: To investigate the biomechanical differences of the treatment of intertrochanteric femoral fractures by proximal femoral anti-rotation intramedullary nail with different tip-apex distances and provide a new idea and experimental basis for the clinical treatment of intertrochanteric fractures. METHODS: CT data of one volunteer were imported into Mimics 19.0 and Geomagic studio 2017 software to extract and optimize the three-dimensional model of the right femur. SolidWorks 2017 software was used to draw the internal fixation model and assemble it with the AO2.1 type fracture femur model in different tip-apex distance according to the standard operation technology. Totally four models with tip-apex distance of 15, 20, 25, and 30 mm were obtained and imported into HyperMesh 14.0 software to mesh. The four models were imported into Abaqus 2016 software in inp format to set up with material property parameters, boundary conditions and applied loads. Finally, operation results were viewed in the visualization module. RESULTS AND CONCLUSION: (1) When tip-apex distance was too large (30 mm) or too small (15 mm), the stress at the proximal femur was reduced, but the displacement of the femur head and neck fragment and the lesser trochanter fragment was larger and the inversion was more serious. When tip-apex distance was in the middle (20, 25 mm), the displacement and varus of femoral head and neck fragment were small, and the lesser trochanteric fragment was basically unshifted. (2) In the treatment of intertrochanteric femur fractures, tip-apex distance should be adjusted to 20-25 mm to reduce displacement and obtain a better biomechanical effect.
RESUMO
Treatment of large bone defects caused by trauma, osteomyelitis, and tumors has been a major challenge in clinical. In the past, there have been many ways to repair and reconstruct the large bone defects. However, there is a long period of treatment, high technical requirement and complications such as ununion. After Masquelet reported the induced membrane technology in 2000, the technique was widely used in treatment of trauma, osteomyelitis, and large bone defects caused by tumors. It has been obtained good results. It has the advantages of short course, high healing rate, easy operation and easy to master. The induced membrane has unique structural characteristics and biological characteristics. There are many kinds of osteogenic factors that are included in the membrane, such as vascular endothelial growth factor, and morphogenetic protein-2, transforming growth factor-β1, etc. These osteogenic factors contribute to accelerate bone healing. With the development of induced membrane technology. The technology of Reamer Irrigator Aspirator technology, engineering tissue technology and internal fixation is used in clinic.It can provide bone source, promote bone defect reconstruction, improve long-term limb function and reduce complications.This paper retrospectively summarizes the experimental research and clinical progress of Masquelet technique in the treatment of large bone defects.