ABSTRACT
BACKGROUND:Many studies have confirmed that recombinant human bone morphogenetic protein 2 plays a very important role in bone formation and fracture healing, but recombinant human bone morphogenetic protein 2 alone implanted is prone to diffusion and degradation, which is unable to play a persistent role in new bone formation. OBJECTIVE:To explore the effect of recombinant human bone morphogenetic protein 2 composite bone in the rabbit lumbar fusion. METHODS:Thirty New Zealand white rabbits were selected to make posterior lumbar intertransverse fusion models, and then were randomly divided into three groups, in which, L5-6 intertransverse implantation of autologous iliac bone, al ogeneic bone and recombinant human bone morphogenetic protein 2 composite bone (recombinant human bone morphogenetic protein 2 and al ogeneic bone complex) was done respectively. At 6 weeks after implantation, gross observation, X-ray examination and histological observation were performed. RESULTS AND CONCLUSION:Fusion rate and percentage of new bone area were higher in the composite bone group than the autologous iliac bone and al ogeneic bone groups (P<0.05);the tensile strength was lower in the al ogeneic bone group than the other two groups (P<0.05), but there was no difference between these two groups except the al ogeneic bone group. X-ray films showed cal us formation in the implanted region of the three groups. In the autologous iliac bone group, a large amount of cartilage tissues formed along with a smal amount of bone trabeculae and a certain amount of woven bones. In the al ogeneic bone group, the implant was covered with a large amount of fibrous tissues, bone island was seen and there was also a smal amount of bone trabeculae and cartilage tissues. In the composite bone group, a great amount of bone trabeculae and cartilage tissues were visible to form woven bone and cortical bone. These findings indicate that the recombinant human bone morphogenetic protein 2 composite bone can obtain good effect in the rabbit lumbar fusion.
ABSTRACT
BACKGROUND:Posterior maleolar fracture is an important factor affecting the prognosis of ankle fractures. Posterior maleolar fracture often caused by high energy trauma. Using what kind of fixation and fixation materials biomechanics, and how to embed has become a current research hotspot. OBJECTIVE:To compare the clinical outcomes of different fixation materials on posterior maleolar fracture, and analyze the effect of different fixation methods on biomechanical outcome of posterior maleolar fracture fixation, so as to provide a basis and reference of selecting the best fixation for the clinical treatment of ankle fracture. METHODS: The relevant literature included by PubMed database and the China National Knowledge database from the year of 1976 to 2015 were retrieved by the first author through computer. English key words are “Ankle fracture; internal fixation; biomechanics; biocompatibility”, Chinese language search terms are “posterior maleolar fracture; internal fixation; biomechanics; biocompatibility”. Summarize the most commonly used metal fixation materials and absorbable content materials. The clinical commonly used metal fixation materials including bone plate and screws, absorbable fixation materials such as biodegradable material polylactic acid, polyethylene plastic ester, polylactide gum ester, etc. The biomechanical properties were analyzed. RESULTS AND CONCLUSION: The new locking screw can withstand more buckling and shear force. Lag screw has a tapping action, and the puling was stronger after tapping, but for patients with osteoporosis, the pressure effect of screw on fracture fragments was limited, the strength was not enough, at this time, locking plate should be used. Locking plate has a greater stability and higher confrontational feature to bending stress, less likely to pul out. Steel coupling screw provides better stability. To avoid secondary removing of the fixation, stress protection after fixation and other shortcomings after the metal material fixation fracture healing, the strength of the absorbable fixation material made by biodegradable material polylactic acid, polyvinyl acetate glue and polypropylene plastic ester after high temperature and pressure processing was increased. Absorbable fixation material may overcome the adverse effects associated with metal fixation, such as imageological examination, secondary implant removal. These results show that the mechanical properties of the absorbable screws are more closer to human bone, no surrounding bone vulnerability due to stress shields, no osteoporosis occurs, and can degrade in the body, but its fixation strength is stil less than the traditional fixed screw and bone plate. We should choose a suitable fixation material according to the forces of fracture site and the size of the fracture fragments.