Objective To investigate the feasibility of Drawtex hydroconductive dressing in treatment of early implantation-associated infection and soft tissue defect after internal fixation of tibial fracture. Methods Thirty-six New Zealand rabbits were used to prepare the model of early implantation-associated infection after internal fixation of tibial fracture, and randomly divided into 3 groups (n=12) . The infected wounds were covered with Drawtex hydroconductive dressing (group A), chitosan solution gauze (group B), and normal saline gauze (group C), respectively. The dressing was changed every 2 days. X-ray films were performed at 1, 14, and 21 days. The gross observation, microbiological evaluation, and histological observation were done at 21 days. Results There was no significant difference in the wound grading according to the Jamesʾ grading criteria between groups at 21 days (χ2=3.713, P=0.156). X-ray films showed no bone destruction in all groups at 1 day; and there was no significant difference in radiographic scores between groups (P>0.05). At 14 days, the mild osteolysis was observed in group B; the radiographic score was significantly lower in groups A and C than in group B (P<0.05), but there was no significant difference between groups A and C (P>0.05). At 21 days, the osteolysis and osteomyelitis were observed in groups B and C; the radiographic score was significantly lower in group A than in groups B and C (P<0.05), but there was no significant difference between groups B and C (P>0.05). Also, the microorganism in bone tissue of group A was less than that of groups B and C (P<0.05); and the difference between group B and group C was not significant (P>0.05). Histological observation showed the mild inflammatory cell infiltration in group A and many inflammatory cells in groups B and C. The Smeltzer histological score was significant lower in group A than in groups B and C (P<0.05); and there was no significant difference between groups B and C (P>0.05). Conclusion Drawtex hydroconductive dressing can be used for the implantation-associated infection after tibial fracture internal fixation. And the effectiveness of Drawtex hydroconductive dressing is better than that of chitosan solution gauze and normal saline gauze.
In order to investigate the mechanical response of lumbar vertebrae during gait cycle in adolescents with idiopathic scoliosis (AIS), the present study was based on computed tomography (CT) data of AIS patients to construct model of the left support phase (ML) and model of the right support phase (MR), respectively. Firstly, material properties, boundary conditions and load loading were set to simulate the lumbar vertebra-pelvis model. Then, the difference of stress and displacement in the lumbar spine between ML and MR was compared based on the stress and displacement cloud map. The results showed that in ML, the lumbar stress was mostly distributed on the convex side, while in MR, it was mostly distributed on the concave side. The stress of the two types of stress mainly gathered near the vertebral arch plate, and the stress of the vertebral arch plate was transmitted to the vertebral body through the pedicle with the progress of gait. The average stress of the intervertebral tissue in MR was greater than that in ML, and the difference of stress on the convex and convex side was greater. The displacement of lumbar vertebrae in ML decreased gradually from L1 to L5. The opposite is true in MR. In conclusion, this study can accurately quantify the stress on the lumbar spine during gait, and may provide guidance for brace design and clinical decision making.