| Objective: The clinical work in the treatment of tibial fracture with plate screws, intramedullary nailing and external fixation for fracture fixation, intramedullary nailing for tibial fixation includes commonly used interlocking intramedullary nail and less application of auto-control micro-movement intramedullary nail and absorbable intramedullary nail and so on. Commonly used clinic treatment of tibial fracture include steel plate screws, intramedullary nailing and external fixation.Intramedullary nailing for tibial fixation includes commonly used interlocking intramedullary nail and automatical interlocking intramedullary nail and less application of auto-control micro-movement intramedullary nail and absorbable intramedullary nail and so on. Current clinical use of intramedullary fixation method is to insert the nail into Centre Medullary cavity along the long axis. Fix the nail to the bone with screws on proximal and distal side respectively. The intramedullary has advantages over the restoration of body length and has a better effect limb lines. But these intramedullary nail using the facet joints or adjacent openings, when reaming and then inserted, thus affect the joint function, such as insert the intramedullary nails with the needle enter point around tibial slope can significantly affect the function of knee joint and cause the limit of range of motion. If the soft tissues condition around the nail enter point is poor at the same time, intramedullary fixation using the traditional approach will dramatically increase the possibility of wound infection, osteomyelitis, and nonunion. Conventional intramedullary nails are longer, across the isthmus of long tubular bone, the nail can easily lead to the nail deformation during inserts, resulting in distal locking difficulty, prolonged operative time and increased radiation exposure in medical personnel and patients. Therefore, we designed a new short-segment tibia intramedullary nail, and compare the intramedullary nail with the classic AO company after fracture of tibial intramedullary nailing fixation of biomechanics, in hopes of better treatment effect can be achieved. Methods: 12 adult specimens(Sichuan Medical university Anatomy teaching and research section provided)include 10 men and 2 woman. Average age of death was 42 years(35-50 years old). After acquiring the lower limbs, removal the surrounding muscles, tendons, ligaments and other soft tissues; dissect the inferior tibiofibular joint, remove the meniscus attachment. Deformities, old fracture, osteoporosis, bone cancer and other diseases of the skeletal system are excluded by visualizing and x ray check. 24 tibia specimens were taken by number(1th-8th), and random number and specimens is divided into group A and B, two groups. Group A is applied with conventional interlocking intramedullary nail for tibial fixation(control group). Group B uses new type short segment of tibia intramedullary nail fixation(the experimental group). From adult cadavers achieved above the articular surface of the distal tibia, tibia 8 root specimen about 12 cm rampages using the wire saw cut off prepared tibial fracture model. In tibial slope Center Office, with openings for the opening, followed by reaming with different diameters, gradually expanding the tibial intramedullary cavity and implanted the chamber reamed intramedullary nailing of the small 1mm, ray confirmed intramedullary nail distal end above the ankle, into and then through the sights are fixed and locked intramedullary nail far proximal locking screws. After two groups of specimens were fixed in biomechanical testing machine, respectively for three-point bending test, axial compression experiments in horizontal torsion test. Collecting measurement data then statistical analysis. Results: Group A(the control group) the displacement of the specimen are 0.251 ± 0.032 cm,0.361 ± 0.028 cm,0.422 ± 0.041 cm respectively, when the axial load are 400 N,600N,800 N. Group B(test group) shift 0.302 ± 0.041 mm,0.412 ± 0.031 mm,0.501 ± 0.025 mm, respectively. Under axial compression stress 800 N, Group A(the control group) the mean flexural rigidity of four specimens is 2095.5N/m, while the Group B(test group) is 1973.2N/m. Data obtained after the homogeneity of variance test, paired samples t test, t=3.0,p>0.05, the difference was not statistically significant.Three-point bending test, group A(the control group) average flexural rigidity of four specimens: 500.80 N·m/°,while the group B(the test group) is 401.86 N·m/°. Data obtained after the homogeneity of variance test, paired samples t test, t=9.849,p<0.05, There are statistically significant differences. Level reverse test by measuring have reverse stiffness, Group A(control group) four specimens reverse stiffness respectively for: 1.94 N·m/°, 2.01N·m/°, 1.53N·m/°, 1.65N·m/°. Group B four specimens reverse stiffness respectively for: 2.04N·m/°, 2.37N·m/°, 1.63N·m/°, 1.84N·m/°.According to the measured data into SPSS software for paired samples t test, t=-3.052, and p>0.05. No significant differences between the overall performance. Conclusions: When combine these two kinds of intramedullary nails in biomechanical testing,we can find that short segments of tibia intramedullary and interlocking intramedullary nail are identical when compared compression stiffness and torsional rigidity. And nail enter points are not subject to too many restrictions, thus we conclude that short segement intramedullary nailing is an effective treatment for tibia fracture. |
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