Accelerated fracture healing by osteogenic Ti45Nb implants through the PI3K–Akt signaling pathway

The key to managing fracture is to achieve stable internal fixation,and currently,biologically and mechanically appropriate internal fixation devices are urgently needed.With excellent biocompatibility and corrosion resistance,titanium–niobium alloys have the potential to become a new generation of internal fixation materials for fractures.However,the role and mechanism of titanium–niobium alloys on promoting fracture healing are still undefined.Therefore,in this study,we systematically evaluated the bone-enabling properties of Ti45Nb via in vivo and in vitro experiments.In vitro,we found that Ti45Nb has an excellent ability to promote MC3T3-E1 cell adhesion and proliferation without obvious cytotoxicity.Alkaline phosphatase(ALP)activity and alizarin red staining and semiquantitative analysis showed that Ti45Nb enhanced the osteogenic differentiation of MC3T3-E1 cells compared to the Ti6Al4V control.In the polymerase chain reaction experiment,the expression of osteogenic genes in the Ti45Nb group,such as ALP,osteopontin(OPN),osteocalcin(OCN),type 1 collagen(Col-1)and runt-related transcription factor-2(Runx2),was significantly higher than that in the control group.Meanwhile,in the western blot experiment,the expression of osteogenic-related proteins in the Ti45Nb group was significantly increased,and the expression of PI3K–Akt-related proteins was also higher,which indicated that Ti45Nb might promote fracture healing by activating the PI3K–Akt signaling pathway.In vivo,we found that Ti45Nb implants accelerated fracture healing compared to Ti6Al4V,and the biosafety of Ti45Nb was confirmed by histological evaluation.Furthermore,immunohistochemical staining confirmed that Ti45Nb may promote osteogenesis by upregulating the PI3K/Akt signaling pathway.Our study demonstrated that Ti45Nb exerts an excellent ability to promote fracture healing as well as enhance osteoblast differentiation by activating the PI3K/Akt signaling pathway,and its good biosafety has been confirmed,which indicates its clinical translation potential.

Bone Injury and Fracture Healing Biology

Bones are organs of the skeletal system, providing shape, mechanical support, and protection to the body and facilitating the movement. In addition, bones contribute to the mineral homeostasis of the body and have recently been found to participate in endocrine regulation of energy metabolism. The well-known limitations associated with clinical use of autografts and allografts continue to drive efforts to develop bone graft substitutes, using the principles of biomaterials and tissue engineering. Under some stressful and continuous compressive conditions, the ability of the bone tissue to tolerate strength decreases. Whenever these forces overcome the toleration of the bone tissue, bone fracture occurs. years

Effects of immune cells on mesenchymal stem cells during fracture healing

In vertebrates,bone is considered an osteoimmune system which encompasses functions of a locomotive organ,a mineral reservoir,a hormonal organ,a stem cell pool and a cradle for immune cells.This osteoimmune system is based on cooperatively acting bone and immune cells,cohabitating within the bone marrow.They are highly interdependent,a fact that is confounded by shared progenitors,mediators,and signaling pathways.Successful fracture healing requires the participation of all the precursors,immune and bone cells found in the osteoimmune system.Recent evidence demonstrated that changes of the immune cell composition and function may negatively influence bone healing.In this review,first the interplay between different immune cell types and osteoprogenitor cells will be elaborated more closely.The separate paragraphs focus on the specific cell types,starting with the cells of the innate immune response followed by cells of the adaptive immune response,and the complement system as mediator between them.Finally,a brief overview on the challenges of preclinical testing of immunebased therapeutic strategies to support fracture healing will be given.

Optimal concentration of mesenchymal stem cells for fracture healing in a rat model with long bone fracture

BACKGROUND There is still no consensus on which concentration of mesenchymal stem cells(MSCs)to use for promoting fracture healing in a rat model of long bone fracture.AIM To assess the optimal concentration of MSCs for promoting fracture healing in a rat model.METHODS Wistar rats were divided into four groups according to MSC concentrations:Normal saline(C),2.5×10^(6)(L),5.0×10^(6)(M),and 10.0×10^(6)(H)groups.The MSCs were injected directly into the fracture site.The rats were sacrificed at 2 and 6 wk post-fracture.New bone formation[bone volume(BV)and percentage BV(PBV)]was evaluated using micro-computed tomography(CT).Histological analysis was performed to evaluate fracture healing score.The protein expression of factors related to MSC migration[stromal cell-derived factor 1(SDF-1),transforming growth factor-beta 1(TGF-β1)]and angiogenesis[vascular endothelial growth factor(VEGF)]was evaluated using western blot analysis.The expression of cytokines associated with osteogenesis[bone morphogenetic protein-2(BMP-2),TGF-β1 and VEGF]was evaluated using real-time polymerase chain reaction.RESULTS Micro-CT showed that BV and PBV was significantly increased in groups M and H compared to that in group C at 6 wk post-fracture(P=0.040,P=0.009;P=0.004,P=0.001,respectively).Significantly more cartilaginous tissue and immature bone were formed in groups M and H than in group C at 2 and 6 wk post-fracture(P=0.018,P=0.010;P=0.032,P=0.050,respectively).At 2 wk post fracture,SDF-1,TGF-β1 and VEGF expression were significantly higher in groups M and H than in group L(P=0.031,P=0.014;P<0.001,P<0.001;P=0.025,P<0.001,respectively).BMP-2 and VEGF expression were significantly higher in groups M and H than in group C at 6 wk postfracture(P=0.037,P=0.038;P=0.021,P=0.010).Compared to group L,TGF-β1 expression was significantly higher in groups H(P=0.016).There were no significant differences in expression levels of chemokines related to MSC migration,angiogenesis and cytokines associated with osteogenesis between M and H groups at 2 and 6 wk post-fracture.CONCLUSION The administration of at least 5.0×10^(6)MSCs was optimal to promote fracture healing in a rat model of long bone fractures.

Mice with a heterozygous Lrp6 deletion have impaired fracture healing

Bone fracture non-unions, the failure of a fracture to heal, occur in 10%-20% of fractures and are a costly and debilitating clinical problem. The Wnt/fl-catenin pathway is critical in bone development and fracture healing. Polymorphisms of linking low-density lipoprotein receptor-related protein 6 （LRP6）, a Wnt-binding receptor, have been associated with decreased bone mineral density and fragility fractures, although this remains controversial. Mice with a homozygous deletion of Lrp6 have severe skeletal abnormalities and are not viable, whereas mice with a heterozygous deletion have a combinatory effect with Lrp5 to decrease bone mineral density. As fracture healing closely models embryonic skeletal development, we investigated the process of fracture healing in mice heterozygous for Lrp6 （Lrp6~/-） and hypothesized that the heterozygous deletion of Lrp6 would impair fracture healing. Mid-diaphyseal femur fractures were induced in Lrp6~^- mice and wild-type controls （Lrp6~/~）. Fractures were analyzed using micro-computed tomography （~CT） scans, biomechanical testing, and histological analysis. Lrp6~/- mice had significantly decreased stiffness and strength at 28 days post fracture （PF） and significantly decreased BV/TV, total density, immature bone density, and mature area within the callus on day-14 and -21 PF; they had significantly increased empty callus area at days 14 and 21 PF. Our results demonstrate that the heterozygous deletion of Lrp6 impairs fracture healing, which suggests that Lrp6 has a role in fracture healing.

Effect of Absorbable Hydroxyapatite/Poly-DL-Lactide Rods on Experimental Fracture Healing

Summary: In order to investigate the effect of a new institute-designed absorbable hydroxyapatite microparticles/poly-DL-lactide (HA/PDLLA) fracture fixation devices on experimental fracture healing, 25 rabbits with a transverse transcondylar osteotomy of the distal femur were fixed in- tramedullary by a HA/PDLLA rod (4. 5 mm in diameter, 30-40 mm in length). The follow-up time lasted 1, 2, 4, 6 and 12 week(s). Roentgenographic, histological and ultrastructural analyses were conducted. The results showed that all osteotomies united within 6 weeks without delay. No accumulation of inflammatory cells was seen. Ultrastructural studies showed that polymorphonuclear neutrophils and macrophages were observed mainly at the 1st week, but only few were noted at the 2nd week. The inflammatory and debridement stages were not prolonged. Large amount of active fibroblasts and some chondroblasts were observed at the 2nd week, suggesting a fibrous callus stage. The main cellularity at 4th week was osteoblasts and osteocytes. Part of osteocytes had already entered the static stage at the 6th week. Our experiment showed that the HA/PDLLA had good biocompatibility, sufficient mechanical strength and caused no delay to the fracture healing.

Effects of Shang Ke Jie Gu tablet on fracture healing in rabbits

Objective:To study the effects of Shang Ke Jie Gu tablet on fracture healing in rabbits.Methods:40 New Zealand rabbits,half male and half female,were randomly divided into two groups:normal saline group(N group)and Shang Ke Jie Gu tablet group(S group).Each group consisted of 20 rabbits.Left radial fracture models in upper and middle sections were made in rabbits and then intra-gastric administration was given.Five rabbits in each group were killed on the 10 th,20^(th),30^(th) and 40^(th) day after surgery,left radius was taken to get an X-ray.The degree of healing was assessed by the evaluation criteria of Shanghai Orthopaedics Institute.Results:The degree of fracture healing in S group was higher in the comparison with that in N group.Conclusions:Shang Ke Jie Gu tablet might affect endochondral ossification during fracture healing of rabbits,and promote porosis and fracture healing.

Experimental observation of rat's early-stage fracture healing with different kinds of nerve injuries

To investigate the impact of different kinds of nerve injuries of early-stage fracture healing.Methods Three groups of rats were included in the experiment among which group 1 was inflicted with femoral fracture and T10 spinal cord transsection (SCI),group 2 was inflicted with femoral and peripheral nerve resection (PNR),and group 3 with simple femoral fracture as control group.Two weeks after operation the femoral bones were collected for X-ray checking and 2 more weeks later X-ray checking was performed again followed by pathomorphologic exams.Results X-ray result showed no massive calluses in the bones in the 2nd week postoperatively,while in the 4th week,callus appeared with larger size in group 3 than that of group 1 and with smaller size than that of group 2.It was the same with the result of pathomorphologic examining.Cortical bone bridges between fracture point and osteiod were also found in group 2 and there were less normal blood vessels and worse bone remodeling than that of group 3.There were relatively immature calluses with more fibroblast-like cells and disordered bone structure in group 2.Group 3 showed normal healing process and callus structure.Conclusion Early-stage bone fracture healing can be influenced significantly by different kinds of nerve injuries.6 refs,6 figs.

Hypoxia inducible factor-1α related mechanism and TCM intervention in process of early fracture healing

As a common clinical disease, fracture is often accompanied by pain, swelling, bleeding as well as other symptoms and has a high disability rate, even threatening life, seriously endangering patients’ physical and psychological health and quality of life. Medical practitioners take many strategies for the treatment of fracture healing, including Traditional Chinese Medicine(TCM). In the early stage of fracture healing,the local fracture is often in a state of hypoxia, accompanied by the expression of hypoxia inducible factor-1α(HIF-1α), which is beneficial to wound healing. Through literature mining, we thought that hypoxia, HIF-1α and downstream factors affected the mechanism of fracture healing, as well as dominated this process. Therefore, we reviewed the local characteristics and related signaling pathways involved in the fracture healing process and summarized the intervention of TCM on these mechanisms,in order to inspirit the new strategy for fracture healing, as well as elaborate on the possible principles of TCM in treating fractures based on the HIF molecular mechanism.

M2 macrophage-derived exosomes promote diabetic fracture healing by acting as an immunomodulator

Diabetes mellitus is a chronically inflamed disease that predisposes to delayed fracture healing.Macrophages play a key role in the process of fracture healing by undergoing polarization into either M1 or M2 subtypes,which respectively exhibit pro-inflammatory or anti-inflammatory functions.Therefore,modulation of macrophage polarization to the M2 subtype is beneficial for fracture healing.Exosomes perform an important role in improving the osteoimmune microenvironment due to their extremely low immunogenicity and high bioactivity.In this study,we extracted the M2-exosomes and used them to intervene the bone repair in diabetic fractures.The results showed that M2-exosomes significantly modulate the osteoimmune microenvironment by decreasing the proportion of M1 macrophages,thereby accelerating diabetic fracture healing.We further confirmed that M2-exosomes induced the conversion of M1 macrophages into M2 macrophages by stimulating the PI3K/AKT pathway.Our study offers a fresh perspective and a potential therapeutic approach for M2-exosomes to improve diabetic fracture healing.

Effect of acupuncture therapy on fracture healing in rats with femur fractures

OBJECTIVE: To investigate the effect of acupuncture therapy on fracture healing in rats with femur fractures.METHODS: A total of 10 groups were formed;control group, groups sacrificed on 7 th, 14 th, and 21 st days of fracture formation, groups to which acupuncture was applied for 7, 14, and 21 d, groups to which fracture and acupuncture were applied for 7,14, and 21 d. A transverse fracture line was formed in femurs of rats by using a Gigli saw. The Kirschner wire was driven retrograde down from the fracture line to proximal part of the bone and then, the fracture was fixed towards distal part. Acupuncture was applied to the rats for 7, 14, and 21 d as 4 sessions per week after formation of the fracture.RESULTS: Malondialdehyde(MDA), reduced glutathione(GSH) levels, catalase(CAT), glutathione-Stransferase(GST), superoxide dismutase(SOD), and glucose-6-phosphate dehydrogenase(G6 PD) activities were measured. Despite the increased MDA levels, G6 PD and SOD activities reduced during the fracture healing. There was a statistically significant increase in MDA, GSH levels, and G6 PD activity in fracture groups compared to control group, but CAT, GST, and SOD activities decreased. The use of acupuncture enhanced callus development and bone mineralization during bone healing.CONCLUSION: The acupuncture therapy can affect suppression of the effects of free oxygen radicals and regulation of the antioxidant enzyme activity in fracture healing. Thus, it is suggested that acupuncture treatment would be beneficial for fracture healing in order to eliminate the negative effects induced by oxygen free radicals.

Chinese topical herbal medicine gives additive effect on pharmaceutical agent on fracture healing

OBJECTIVE:To investigate the efficacy on the combination of oral strontium ranelate(Sr R)with a topical Chinese herbal paste on facilitation of fracture healing.METHODS:An open fracture was created at the mid-shaft of the right tibia of rat.A herbal pastecalled CDR containing Honghua(Flos Carthami),Chuanxuduan(Radix Dipsaci Asperoidis)and Dahuang(Radix Et Rhizoma Rhei Palmati)was prepared.The rats were treated with either CDR topically on the fracture site,or Sr R orally,or their combinations.Bone turnover biochemical markers in serum were measured.Microarchitecture of the fracture was analyzed using micro-CT after 14 and 28 d,followed by histomorphometrical analysis.RESULTS:Micro-computed tomography analysis revealed that the combined treatment of CDR with600 mg/g Sr R significantly increased the total callus density,mineralized callus volume fraction,mineralized callus mineral content and mineralized callus density of the callus after 28 d of treatment.This result was consistent with the histomorphometrical analysis on the osteoid volume.Analysis of biochemical markers showed that the combined treatments reduced the bone resorption that occurs temporarily after fracture.CONCLUSION:This study demonstrated that the combined treatment of oral Sr R and topical CDR is effective to promote fracture healing by their additive effect on promoting bone formation and retarding bone resorption.

Exosomal PD-L1 induces osteogenic differentiation and promotes fracture healing by acting as an immunosuppressant

A moderate inflammatory response at the early stages of fracture healing is necessary for callus formation.Over-active and continuous inflammation,however,impairs fracture healing and leads to excessive tissue damage.Adequate fracture healing could be promoted through suppression of local over-active immune cells in the fracture site.In the present study,we achieved an enriched concentration of PD-L1 from exosomes(Exos)of a genetically engineered Human Umbilical Vein Endothelial Cell(HUVECs),and demonstrated that exosomes overexpressing PD-L1 specifically bind to PD-1 on the T cell surface,suppressing the activation of T cells.Furthermore,exosomal PD-L1 induced Mesenchymal Stem Cells(MSCs)towards osteogenic differentiation when pre-cultured with T cells.Moreover,embedding of Exos into an injectable hydrogel allowed Exos delivery to the surrounding microenvironment in a time-released manner.Additionally,exosomal PD-L1,embedded in a hydrogel,markedly promoted callus formation and fracture healing in a murine model at the early over-active inflammation phase.Importantly,our results suggested that activation of T cells in the peripheral lymphatic tissues was inhibited after local administration of PD-L1-enriched Exos to the fracture sites,while T cells in distant immune organs such as the spleen were not affected.In summary,this study provides the first example of using PD-L1-enriched Exos for bone fracture repair,and highlights the potential of Hydrogel@Exos systems for bone fracture therapy through immune inhibitory effects.

Effect of fluvastatin on vascular endothelial growth factor in rats with osteoporosis in process of fracture healing

Objective: To explore the effect of fluvastatin on vascular endothelial growth factor (VEGF) in rats with osteoporosis in the process of fracture healing.Methods: Fractures at the intermediate piece of the femur were made on 72 Sprague Dawley (SD) rats (weighing initially 290-340 g and aged 6 months ) with osteoporosis after ovariectomy for three months, then these rats were divided randomly into the medication administration group (the experimental group ) and the control group, 36 rats each. In the experimental group, the rats received fluvastatin lavage (10 mg/kg per day) since the next day of operation lasting for 6 weeks, and the rats in the control group received placebo. Then the expression of VEGF and VEGF mRNA in bony callus of the two groups was measured respectively with immunohistochemistry and in situ hybridization on days of 3rd, 7th, 14th, 21st, 28th, and 42nd, and image analysis was made with real-color image analysis machine.Results: No difference was found in the cellular localization of VEGF and VEGF mRNA gene expression between the experimental group and the control group in process of fracture healing and their expression modes were almost similar. On the 14th day postoperatively, the positive extent of positive cells in the experimental group was higher than that of the control group (P ＜ 0.05).Conclusion: Fluvastatin can promote the VEGF level in rats with osteoporosis in process of fracture healing.

Image Analysis in the Experimental Fracture Healing under Cyclic Loading

This experimental study was designed to evaluate the ef-fects of cyclic loading on the strength of healing fractures

Piezoelectric-Based Smart Bone Plate for Fracture Healing Progress Monitoring

Fracture healing progress monitoring techniques attract global research attention due to the importance of selecting the timing of removing the fixation device.To this end,in this research,we present a piezoelectric-based smart internal fixation device,in which a piezoelectric sandwich structure is laminated to the surface of a bone plate.In the content,we explain the reasons for utilizing piezoelectric films,elaborate the mechanism of fracture monitoring,and introduce the mechanical parameters of the sensor.The simulation and experimental results show that the electrical output of the device is associated with the elastic modulus of the filler between the tested broken bones when the working load is maintained,indicating that the bone recovery progress could be successfully detected by the developed technique.

Constructing the toolbox:Patient-specific genetic factors of altered fracture healing

The multifaceted sequence of events that follow fracture repair can be further complicated when considering risk factors for impaired union,present in a large and growing percentage of the population.Risk factors such as diabetes,substance abuse,and poor nutrition affect both the young and old,and have been shown to dramatically impair the body’s natural healing processes.To this end,biotherapeutic interventions such as ultrasound,electrical simulation,growth factor treatment(BMP-2,BMP-7,PDGF-BB,FGF-2)have been evaluated in preclinical models and in some cases are used widely for patients with established non-union or risk/indication or impaired healing(i.e.ultrasound,BMP-2,etc.).Despite the promise of these interventions,they have been shown to be reliant on patient compliance and can produce adverse side effects such as heterotopic ossification.Gene and cell therapy approaches have attempted to apply controlled regimens of these factors and have produced promising results.However,there are safety and efficacy concerns that may limit the translation of these approaches.In addition,none of the above mentioned approaches consider genetic variation between individual patients.Several clinical and preclinical studies have demonstrated a genetic component to fracture repair and that SNPs and genetic background variation play major roles in the determination of healing outcomes.Despite this,there is a need for preclinical data to dissect the mechanism underlying the influence of specific gene loci on the processes of fracture healing,which will be paramount in the future of patient-centered interventions for fracture repair.

Factors Affecting Time to Healing in Humeral Shaft Fractures Treated with SIGN Intramedullary Nailing

There is a tendency to treat humeral fractures with the use of splintage in resource poor countries due to a perceived high rate of complications with operative fixation. The Surgical Implant Generation Network (SIGN) intra medullary nail has provided an alternative in the management of humeral shaft fractures. Due to the paucity of research work in this area, our study evaluated factors that influence the time to fracture union in humeral shaft fractures. Fifty-eight humeral Diaphysial fractures were treated over six years. It is a retrospective study. Case notes and the database were analysed. The statistical analysis was done using the SPSS 24 software. The time to fracture healing was the primary outcome variable and how it was influenced by patient and implant variables was studied. The mean time to fracture healing was 17.38 weeks. All 58 fractures united. The mean time to fracture healing in the 20 - 29 years was 16.00 weeks which was lower than in older age groups. Fractures in males healed at 16.33 weeks and in females at 18.76 weeks. Patients with Diabetes Mellitus had a mean healing time of 29.00 weeks, while third proximal fractures healed in a mean time of 15.25 weeks. Age and sex had no significant influence on the time to fracture healing while Diabetes Mellitus, longer duration of antibiotic use, open fractures, and presence of fracture gap post fixation and third middle fractures had increased time to fracture healing.

Research of the molecular mechanism of Hai Honghua medicinal liquor in the treatment of fracture based on network pharmacology combined with molecular docking

Background:Hai Honghua medicinal liquor(HHML),a famous hospital formula composed of 19 traditional Chinese medicines,has been successfully applied in treating soft tissue injury,fresh closed fracture,limb dysfunction after fracture healing,shoulder,neck and leg pain,knee joint pain and other clinical multiple diseases for 30 years in clinical.However,research on the material basis of HHML for the treatment of fracture healing-related disorders is still in a gap.Therefore,it is particularly important to explore the active ingredients,core targets and potential pharmacological mechanisms of HHML to promote fracture healing.Methods:We screened the core active components of each traditional Chinese medicine in formula and its action targets through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and Encyclopedia of Traditional Chinese Medicine database.The fracture related targets were retrieved from several different public databases,including GeneCards,Online Mendelian Inheritance in Man,DisGeNET and Therapeutic Target Database.Bioinformatics analysis to obtain key bioactive components,underlying targets and signaling pathways,containing the Venn diagram of the intersection with components and diseases gene targets,protein–protein interaction,as well as the Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes analysis,and finally molecular docking.Results:A total of 249 bioactive ingredients of HHML and 325 HHML-fracture-related targets were screened.The network analysis revealed that quercetin,luteolin,kaempferol,Licochalcone A,naringenin and 8-Isopentenyl-kaempferol may be potential candidate agents.Multiple targets are involved including TP53,MAPK3,STAT3,AKT1,MAPK1,HSP90AA1,ESR1 and PIK3CA may be closely linked targets.PI3K-AKT signaling pathway may play a significant role of HHML in treatment of fracture.What’s more,molecular docking suggested that 8-isopentenyl kaempferol,glycyrrhiza chalcone A,and naringenin bound to AKT1,PIK3CA,and ESR1,respectively,exhibiting lower energy and more stable characteristics.Conclusions:The findings indicate the potential active ingredients,target proteins and molecular mechanisms of HHML for the treatment of fractures to provide the exact idea for the next research on the mechanism of action of HHML formula for fracture treatment.

Experimental Study on Anatomic Reduction of Lateral Pterygoid Muscle(Simulated Manipulation Fracture Reduction)and Condylar Free Reduction for Condylar Fracture

[Objectives]To compare the fracture healing of keeping lateral pterygoid muscle anatomic reduction(simulated manipulation fracture reduction)with condylar free reduction in the treatment of condylar fractures.[Methods]Twenty-four New Zealand rabbits were randomly divided into two groups to mandibular condylar neck fracture model was established.one team keep the lateral pterygoid muscle,the other excise it.Cervical vascular perfusion was done with ink before animals executed after operation 2,4,6 and 8 weeks.Bilateral anteroposterior and mediolateral condylar diameters measured.Changes of operation side condylar proliferating layer,microvessel number and bone parameters were observed and analyzed after slices and HE staining.[Results]The mediolateral condylar diameters of operation side were significantly smaller than health side in condylar free reduction group at the 4,6,8 weeks(P<0.05),but there was no statistical difference in the anteroposterior condylar diameters at each time point(P>0.05).There were no significant differences in the anteroposterior and mediolateral condylar diameters of the anatomic reduction lateral pterygoid muscle group compared between the operation side and health side(P>0.05).The number of microvessel in condylar free reduction group were smaller than those in anatomic reduction lateral pterygoid muscle group(P<0.05).There were significant differences in BV/TV,Tb.Th,Tb.Sp between the condylar free reduction group and the anatomic reduction lateral pterygoid muscle group(all P<0.05),and the Tb.N were significantly differences between two groups at the 4,6,8 weeks(P<0.05).[Conclusions]When the condyle is fractured it should keep lateral pterygoid muscle(manipulation fracture reduction)as possible,which is important in the fracture healing and functional recovering of mandibular.