Transoral stepped atlantoaxial release theory for irreducible atlantoaxial dislocation / 中华骨科杂志

Objective:To investigate the clinical efficacy of different grade transoral atlantoaxial release for the treatment of irreducible atlantoaxial dislocation.Methods:From January 2010 to December 2019, 297 patients with irreducible atlantoaxial dislocation treated by different grade releases were retrospectively analyzed, including 132 males and 165 females, aged 42.3±12.14 years (range, 10-63 years). All cases were treated by different grade releases, Grade I (196, 66.0%), Grade II (54, 18.2%), Grade III (28, 9.4%) and Grade IV (19, 6.4%). The American Spinal Injury Association (ASIA) grade and Japanese Orthopedic Association (JOA) score were recorded as the clinical evaluation index. The clivus-canal angle (CCA) and cervico-medullary angle (CMA) were measured to evaluate the reduction. The surgery time, blood loss, duration of bony fusion and complications were also analyzed.Results:The follow-up time was 14.8±10.2 months (range, 9-36 months). The surgery time of Grade I-IV were 2.02±0.35 min, 3.00±0.36 min, 4.07±0.96 min and 5.24±0.83 min, respectively ( F=385.43, P<0.001), blood loss was 84.08±27.21 ml, 153.61±31.36 ml, 268.93±48.94 ml and 444.21±109.51 ml, respectively ( F=582.39, P<0.001). The preoperative ASIA motor score of Grade I-IV were 83.85±6.68, 84.06±5.47, 84.07±5.99 and 85.00±4.11, respectively. The last follow-up were 98.34±2.38, 98.67±1.79, 98.86±1.58 and 98.32±2.11, respectively, with statistically significant differences from preoperative ( P<0.05). The preoperative JOA score of Grade I-IV were 11.44±1.73, 11.59±1.72, 11.61±1.47 and 11.32±1.80, respectively. The last follow-up were 16.22±1.00, 16.28±1.02, 16.14±1.04 and 16.16±1.07, respectively, with statistically significant differences from preoperative ( P<0.05). The preoperative CCA of Grade I-IV were 110.19°±8.76°, 112.48°±7.66°, 106.61°±6.54° and 109.05°±7.79°, respectively. The last follow-up were 140.22°±8.04°, 141.86°±7.04°, 142.35°±8.62° and 140.15°±6.49°, respectively, with statistically significant differences from preoperative ( P<0.05). The preoperative CMA of Grade I-IV were 113.48°±9.54°, 116.03°±8.38°, 109.55°±7.13°, and 112.46°±8.33°, respectively. The last follow-up were 144.28°±7.75°, 146.40°±6.98°, 145.81°±8.27° and 143.24°±6.36°, respectively, with statistically significant differences from preoperative ( P<0.05). Solid bony fusion was obtained except for 3 cases, the fusion time was 9.71±2.55 months (range 3-14 months). Altogether 33 complications occurred in all cases (11.1%), including 3 fusion failure, 3 cerebrospinal leak, 3 wound infection, 2 death (1 case caused by cerebrospinal leak), 11 pharyngeal discomfort, 4 postoperative pain surrounding iliac crest, and 8 malunion of iliac crest. Conclusion:Transoral stepped atlantoaxial release theory could provide guidelines for atlantoaxial dislocation treatment, and make the transoral release technique more effective and safer.

Comparison of Jefferson-fracture reduction plate and micro titanium plate in the transoral single-segment fixation of unstable atlas fractures / 中华创伤骨科杂志

Objective:To compare Jefferson-fracture reduction plate (JeRP) and micro titanium plate in the transoral single-segment fixation of unstable atlas fractures.Methods:From January 2008 to December 2020, 45 patients with unstable atlas fracture were treated by single-segment fixation through an oral approach with a JeRP or a micro titanium plate at Department of Orthopedic Surgery, General Hospital of Southern Theatre Command. They were 24 males and 21 females, aged from 15 to 67 years. By the Gehweiler classification, 11 atlas fractures were type Ⅰ and 34 type Ⅲ; by the American Spinal Injury Association (ASIA) classification, the spinal cord injury was grade D in 7 cases and grade E in 38 cases; by the Dickman classification, the atlas transverse ligament injury was type Ⅰ in 4 cases and type Ⅱ in 11 cases. Of the patients, 26 were treated by transoral single-segment fixation with a JeRP and 19 by transoral single-segment fixation with a micro titanium plate. The 2 groups were compared in terms of baseline data, operation time, blood loss, hospital stay, visual analog scale (VAS) for neck pain and atlas lateral mass displacement (LMD) before operation and at the last follow-up, and intraoperative and postoperative complications.Results:The 2 groups were comparable because there was no significant difference between them in the preoperative general data ( P>0.05). All patients were followed up for 12 to 55 months (mean, 21.8 months). Wound dehiscence or infection was observed in none of the patients after operation. About 12 months after operation, all fractures achieved bony union, neck pain basically disappeared, and neck movement had no obvious limitation. The hospital stay was (13.9±2.2) d for the JeRP group and (14.2±2.9) d for the micro titanium plate group, showing no significant difference between the 2 groups ( P>0.05). The operation time was (203.5±173.4) min and the blood loss (167.3±138.6) mL in the JeRP group, significantly more than those in the micro titanium plate group [(121.5±50.5) min and (98.4±57.2) mL] ( P<0.05). In the JeRP group, the preoperative LMD was (6.7±1.7) mm and the preoperative VAS score (6.8±1.0) points, significantly higher than the last follow-up values [(0.7±0.6) mm and (0.7±0.6) points] ( P<0.05). In the micro titanium plate group, the preoperative LMD was (6.6±1.5) mm and the preoperative VAS score (6.7±0.9) points, significantly higher than the last follow-up values [(0.9±0.6) mm and (0.8±0.7) points] ( P<0.05). However, there was no significant difference in the preoperative or the last follow-up comparison between the 2 groups ( P>0.05). Implant loosening was observed in one patient in the JeRP group while foreign body sensation in the throat was reported in one patient after operation in the micro titanium plate group. Conclusions:Both JeRP and micro titanium plate in the transoral single-segment fixation can lead to effective treatment of unstable atlas fractures. Compared with JeRP, the micro titanium plate can effectively shorten operation time and reduce blood loss due to its smaller size and lower incision.

Diagnosis and treatment of posterior atlantoaxial dislocation with odontoid retrolisthesis / 中华创伤骨科杂志

Objective:To report our experience in diagnosis and treatment of posterior atlantoaxial dislocation with odontoid retrolisthesis.Methods:A retrospective study was conducted of the 5 patients who had been treated from July 2012 to August 2018 at Department of Orthopaedics, General Hospital of Southern Theater Command for posterior atlantoaxial dislocation. They were 4 men and one woman, aged from 34 to 67 years (average, 47 years). All of them had a history of trauma. Of them, 4 were complicated with odontoid fracture and one with congenital free os odontoideum. Their posterior atlantoaxial dislocation ranged from 3 to 9 mm (average, 6 mm). By the American Spinal Injury Association (ASIA) grading system, their preoperative spinal injury was rated as grade B in one, as grade C in 3 cases and as grade D in one. All the 5 patients underwent skull traction at 10° flexion. Surgical trans-oralpharyngeal atlantoaxial reduction and internal fixation was performed for the one patient whose reduction had not been achieved by traction while posterior atlantoaxial screw-rod fixation or anterior odontoid screwing was conducted for the 4 patients whose reduction had been achieved by traction. The distance of posterior atlantoaxial dislocation was measured to evaluate their reduction and ASIA grade system was used to assess their spinal function after operation.Results:The postoperative distance of posterior atlantoaxial dislocation was 0 mm, showing a reduction rate of 100%. The 5 patients were followed up for 6 to 36 months (average, 15 months). By the ASIA grade system, the postoperative functional recovery of the spine was grade D in 4 cases and grade C in one. No implant loosening or breakage occurred.Conclusion:As a kind of high-energy hyperextension injury, posterior atlantoaxial dislocation is rare in clinic, but an appropriate treatment can be adopted to deal with its different clinical types to achieve good outcomes.

Navigational template applied in the orthopaedic field in China: a bibliometric analysis / 中国组织工程研究

BACKGROUND: With the rapid development of digital orthopaedics, navigational template has been widely used in the field of orthopaedics, but the research status of the technique in China based on bibliometric analysis is never reported. OBJECTIVE: To investigate the application status of navigational template in the orthopaedic field and to explore its tendency and hot spot based on bibliometric analysis, thereby providing reference for the development of digital orthopaedics in China.METHODS: A computer-based retrieval of CBMdisc, CNKI, CSPD, CMCI databases was conducted for articles published before December 1, 2016 using the keywords of navigational template and subject heading orthopaedics and the core orthopaedic journals published in 2016 were searched by manual. The articles were screened according to inclusion and exclusion criteria, and finally were analyzed by bibilometric study.RESULTS AND CONCLUSION: (1) In China, the first paper reporting navigational template was issued in 2008. A total of 199 articles were published in the past 9 years, with more than 10 papers yearly from 2009 to 2014, while there was a rapid increase tendency during 2015 and 2016. (2) The articles were mainly published in the orthopaedic journals and some professional journals closely related to digital orthopaedics, such as biomedical engineering, basic medicine and digital medicine. About 86.9% papers belong to Chinese core journals, including Chinese Journal of Orthopaedic Trauma,Chinese Journal of Orthopaedics, and Chinese Journal of Tissue Engineering Research. (3) There is a 99.5% cooperation rate and 6.15 degree of cooperation. Zhang Yuan-zhi, Ding Huan-wen, Lu Sheng, Chen Yu-bing, Hu Yong,Huang Xuan and Zheng Peng-fei are most productive authors, and core authors contribute to 53.8%, indicating that the group of core authors is being formed. First authors are all from hospitals and universities, mostly from Kunming General Hospital of Chengdu Military Command of PLA, General Hospital of Guangzhou Military Command of PLA, the Affiliated Hospital of Inner Mongolia Medical University and South China University of Technology. The cooperation rate of more than two institutes occupies 54.8%, indicating that the study holds a promising future with the strong support of research institutes in universities. About 59.3% articles are sponsored by funding, the national and provincial foundations accounting for 64.0% in 239 projects, and 57.6% articles were supported by more than two foundations, revealing the high research levels and academic values of this technique. (4) The articles are cited by 763 times; Lu Sheng,Chen Yu-bing, and Zhang Yuan-zhi are the highly cited authors; Kunming General Hospital of Chengdu Military Command of PLA, General Hospital of Guangzhou Military Command of PLA and Nanfang Hospital of Southern Medical University are the highly cited institutes, and Chinese Journal of Orthopaedic Trauma is the highly cited journal. (5) To conclude, based on product design, manufacture and cadaver studies of the navigational template, it has been extensively applied in the spine surgery (especially cervical surgery), orthopaedic traumatology, bone and joint surgery,bone tumor and pediatric orthopaedics, and has obtained satisfactory clinical outcomes in assisting screw placement,osteotomy and precise resection and functional reconstruction. However, there is still a lack of a large-sample,multicenter, and long-term randomized trial.

Posterior screw-rod fixation fusion for the treatment of atlantoaxial dislocation due to rheumatoid arthritis / 中华骨科杂志

Objective To investigate the clinical effect of posterior screw-rod fixation fusion for the treatment of atlantoaxial dislocation due to rheumatoid arthritis.Methods From January 2011 to December 2015,15 patients with atlantoaxial dislocation due to rheumatoid arthritis were treated,including 6 males and 9 females,aged 35 to 75 years (mean 55 years).All cases were evaluated about the difficulty of relocation by extension-flexion X-ray and treated with posterior screw-rod reduction,fixation and autogenous bone grafting under general anesthesia.Atlantodental interval (ADI) was measured and collected before and after surgery.Visual Analogue Scale/Score (VAS),American Spinal Cord Injury Association (ASIA) and Japanese Orthopaedic Association (JOA) scores were comprehensively used to evaluate the clinical effect.1 week,3,6,12 months postoperatively and the annual review of the X-ray and CT were checked,in order to evaluate the reduction,internal fixation and bone graft fusion.Results All patients were reducible dislocation and successfully performed the posterior screw-rod fixation fusion surgery.The patients were followed up for 3 to 24 months (average,15 months).Atlantoaxial solid bony fusion was obtained from 3 to 6 months.ADI reduced from preoperative 6.3±1.7 mm to postoperative 2.2±0.8 mm,VAS score reduced from preoperative 5.4±2.7 to postoperative 1.7±1.0,ASIA motor score improved from preoperative 82.3±15.6 to 95.3±4.5 at 6 months after the surgery,JOA score increased from preoperative 13.8±2.9 to 15.5±1.4 at 6 months after the surgery,and the statistical significance was revealed between preoperation and postoperation.Nine cases were in D grade of ASIA,3 cases improved from D to E grade after surgery,2 cases reached E grade in the other 6 cases after 6 months,2 cases recovered to E grade after 12 months and other 2 cases in D grade got uniformity after surgery.Well internal fixation and no redislocation were found on X-ray and CT during follow-up period.Conclusion Atlantoaxial dislocation because of rheumatoid arthritis was numerously reducible genre.Posterior screw-rod fixation and autogenous bone grafting can gain satisfying clinical efficacy.

Mechanical property of silver-loaded coralline hydroxyapatite bone in the repair of large segmental contaminative radial defects / 中国组织工程研究

BACKGROUND:Scholars have made certain progress in the basic and clinical studies regarding antibacterial bone graft materials. OBJECTIVE: To investigate the mechanical property of antimicrobial silver-loaded coral hydroxyapatite bone usingin vitro mechanical experiments and to explore its ability to repair large segmental contaminative bone defects. METHODS:Compression test and three-point bending test were used to evaluate the mechanical properties of silver-load coraline hydroxyapatite, coraline hydroxyapatite and coral. Thirty-six New Zealand white rabbits were selected and randomly divided into four groups to establish right-side large segment of contaminative radial bone defect models. Rabbits in three groups were implanted silver-load coraline hydroxyapatite, coraline hydroxyapatite andin situ autologous bone, and rabbits in the other group were not implanted any material (as control). At 2, 6 and 10 weeks post-operation, the rabbits were sacrificed to take specimens. The repair of bone defects in each group was observed and compared by gross observation, radiographic examination and histological examination. The antimicrobial condition in each group was evaluated by bacteriological examination. RESULTS AND CONCLUSION:There was no significant difference between the mechanical properties of silver-load coraline hydroxyapatite, coraline hydroxyapatite and coral. At the 10th week post-operation, X-ray and histological observation showed mature bone tissues in the silver-load coraline hydroxyapatite bone group. A large number of lacunae and mature bone cels were visible in bone tissues. Haversian system was visible. Most of the materials were degraded, and there was only a smal amount of residual material. Partial recanalization was visible in bone marrow cavity. The repair effect of silver-load coraline hydroxyapatite bone group was similar with the autologous bone group, and better than the coraline hydroxyapatite group and the control group. Bacteriological examination showed that the silver-load coraline hydroxyapatite had good antibacterial ability. These results demonstrate that the silver-load coraline hydroxyapatite has good mechanical properties and antibacterial properties, which can be used to repair large segmental contaminative bone defects.

Effect of different functional groups on self-assembled monolayers on the biological characteristics of skeletal muscle cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the effect of different functional groups on self-assembled monolayers on the biological characteristics of rabbit skeletal muscle cells in vitro.</p><p><b>METHODS</b>Rabbit skeletal muscle cells were cultured on self-assembled monolayers of gold on which different terminal chemical groups including methyl groups (-CH(3)), amino(-NH(2)), hydroxyl(-OH) and carboxyl (-COOH ) were anchored with self-assembled methods. Contact angle measurements and atomic force microscopy were employed to confirm the similar density of different functional groups occupation. Fluorescence microscopy, MTT assay, flow cytometry, and scanning electron microscopy (SEM) were used to analyze the morphological and biological alterations of the cells.</p><p><b>RESULTS</b>SEM results revealed that the chemical groups on the surface of the monolayer modulated the structure of skeletal muscle cells and the cell morphology. Skeletal muscle cells cultured on the monolayer with -CH3 exhibited the smallest contact area with a spherical morphology, while the cells on the monolayers with -NH(2), -OH and -COOH showed much larger contact area and flatter morphology. The functional groups -NH(2) and -COOH obviously promoted cell adhesion and proliferation, while -CH(3) group produced significantly greater toxicity than -NH(2), -OH and -COOH groups to inhibit the cell growth and adhesion and promote cell death. Cell attachment and growth was enhanced, in the order the magnitude of the effect, by -NH(2)>-COOH>-OH>-CH(3), and the toxicity decreased in the order of -NH(2)>-COOH>-OH>-CH(3).</p><p><b>CONCLUSION</b>The terminal chemical groups can obviously affect the phenotype of skeletal muscle cells in vitro, and this finding provides a theoretical basis for surface design of biomaterials.</p>

Development of articular cartilage repair technique / 中国组织工程研究

BACKGROUND:Autologous cartilage has a poor self-repair effect due to low chondrocyte density, low metabolism rate and no blood supply. OBJECTIVE:To summarize the recent study about tissue engineering techniques and surgical treatment for cartilage injury. METHODS:A computer-based online retrieval of PubMed database was performed by the first author for articles published between January 1992 and December 2013. The key words are“articular cartilage, injury, tissue engineering, repair”in English. According to the inclusion and exclusion criteria, 61 literatures were included into the final analysis. RESULTS and CONCLUSION:The current clinical treatment of articular cartilage injury includes joint debridement, mosaicplasty, perichondrium transplantation and autologous chondrocyte implantation. However, their long-term result is unsatisfactory. One reason for limited clinical success is that new cartilage can be formed at the site of a defect, and the repaired tissue canot compare with the autologous cartilage in mechanical property. Tissue engineering technique is stil a hot topic in recent years, because it can potential y induce autologous cartilage formation. Through endogenous or ectogeneous seed cells and inducting factor and nutrient factors, tissue engineering technique can be applied to induce the self-repair of articular cartilage, thus regenerating into hyalinc cartilage with the similar even same biological property. How to simplify the treatment protocols and reduce treatment cost is the key to promote cartilage repair.

Effects of nanonetwork topography on bone marrow mesenchymal stem cell bioactivity / 中国组织工程研究

BACKGROUND:Many studies have shown that different nanostructures produce different influences on cellbioactivity, but the nanonetwork structure is not reported yet. OBJECTIVE:To study the influence of the nanonetwork topography on the bioactivity of bone marrow mesenchymal stem cels. METHODS:The nanonetwork topography was fabricated on biomedical titanium surface by alkali-heat treatment, and pure titanium served as control group. Bone marrow mesenchymal stem cels were co-cultured with the above two types of samples. cellmorphology and cytoskeleton were observed using scanning electron microscope and immunofluorescence method. The celladhesion, proliferation and osteogenic differentiation were detected by measurement of absorbance values at different culture time. RESULTS AND CONCLUSION: The nanonetwork topography had significant advantage on the number of adherent cels at 30, 60 and 120 minutes of co-culture. The cellproliferation was significantly accelerated by the nanonetwork topography at days 1, 3, 5 of co-culture, and the absorbance values in the nanonetwork group were significantly higher than those in the pure titanium group (P < 0.05). The alkaline phosphatase activity in the nanonetwork group was also significantly higher than that in the pure titanium group at 14 days of osteogenic induction (P < 0.05). The cellshape and cytoskeleton on the nanonetwork surface were better than those on the titanium surface. These findings indicate that the nanonetwork topography has better effects on cellbioactivity compared with pure titanium.

Sensitization test of the digital coralline hydroxyapatite artificial bone scaffold at the maximal dosage / 中国组织工程研究

BACKGROUND:We have successfuly prepared digital coraline hydroxyapatite artificial bone scaffold in previous experiments, and it has been confirmed that it has the necessary physical and chemical properties of bone tissue engineering scaffolds. OBJECTIVE: To evaluate the sensitization of digital coraline hydroxyapatite artificial bone scaffold. METHODS:A total of 32 guinea pigs were randomly divided into saline group (negative control group, n=8), 5% formaldehyde group (positive control group,n=8), experimental A group (the mass ratio of 3:1,n=8), and experimental B group (the mass ratio of 4:1,n=8). Sensitization test at the maximal dosage was performed according toBiological Evaluation of Medical Devices-Part 10: Tests for Irritation and Delayed-Type Hypersensitivity, including intracutaneous induction, local induction, and provocation. Patch was removed after 24 and 48 hours, and the skin response was classified according to Magnusson and Kligman criteria. Patch was removed after 48 hours, and the skin was performed with biopsy, stained with hematoxylin-eosin, and observed under optical microscope. RESULTS AND CONCLUSION: Sensitization response was not tested in the negative control group, experimental A group and experimental B group at 24 and 48 hours after patch removal; however, moderate erythema was observed in the positive control group. Optical microscope demonstrated that spongiosis, edema, diffuse or perivascular mononuclear infiltration was not observed, and only a smal number of basicytes were seen in the experimental A and B groups. These findings indicate that the digital coral hydroxyapatite artificial bone scaffolds, with the mass ratio of 3:1 and 4:1, are biologicaly safe for sensitization.

Alcohol affects the femoral head intramedullary adipocytes / 中国组织工程研究

BACKGROUND:Alcohol has become pathogenic factors of avascular necrosis, and the alcohol induced abnormal lipid metabolism in bone marrow may be the important reason for the onset of avascular necrosis, but the mechanism is not clear yet. OBJECTIVE:To observe the changes of structure and function of fat cel s under the action of alcohol, in order to analyze the pathogenesis of alcoholic femoral head necrosis. METHODS:Primary adipocytes in vitro culture technique was used to obtain rabbit femoral head intramedul ary adipose tissue, and then the fat cel s were separated, and the phenotype was identified with oil red O staining. The passaged stable intramedul ary fat cel s were col ected. Coverslip was cut into 1 cm × 1 cm in size, and placed in the 24-wel culture plate before planting. The cel s were randomly divided into alcohol group and control group, 24 holes (each hole for a sample) in each group. The control group was without alcohol, while the alcohol group was added with 0.15 mol/L alcohol. At 4, 6, 8 and 10 days, the culture medium was replaced. Medium was changed and no longer adding alcohol, and then cultured for 10 days. When the culture terminated, the coverslip was removed for oil red O staining. Final y, the morphology and the number of the fat cel s were observed under light microscope. RESUTLS AND CONCLUSION:With time prolonging, the number of fat cel s in the alcohol group was significantly more than that in the control group (Pnumber of intramedul ary fat cel s in the control group was respectively (99.80±10.82), (0.40±94.71), (1 000.20± 41.85) and (1 059.80±26.79)/cm2, the number of fat cel s increased with the time of alcohol influence. Alcohol can promote the intramedul ary fat cel s to increase and enlarge, and this may be the main reason for femoral head necrosis, as long-term alcoholism can lead to bone marrow fat tissue increasing, intraosseous pressure increasing and perfusion reducing, thus resulting ischemia.

Preparation and ectopic bone formation activity of recombinant human bone morphogenetic protein-2 loaded chitosan nanospheres in vivo / 中华创伤骨科杂志

Objective To prepare recombinant human bone morphogenetic protein-2(rhBMP-2)loaded chitosan nanospheres and to evaluate their ectopic bone formation activity in vivo. Methods The rhBMP-2 loaded chitosan nanospheres were prepaid using the ionic crosslinking method with TPP as a crosslinking agent.The morphological properties and particle size distribution were evaluated by transmission electron microcopy(TEM) and particle size analyzer.An intramuscular ectopic bone formation test was carried out to compare the ectopic bone formation activity in 24 SD rabbits that were randomized into 4 even groups.rhBMP-2 loaded chitosan nanospheres (1 mg),rhBMP-2 (1 mg),chitosan nanospheres and nothing were implanted into the muscle pouch at the left thigh,respectively,in groups A,B,C and D. Results The rhBMP-2 loaded chitosan nanospheres were well distributed and spherical in shape.The average particle diameter was 230.0 nm,the entrapment efficiency was 66.87％ ± 4.58％,and the loading rate was 33.44 ± 2.29 μg/mg.The mean ALP activity was respectively 1.94 ± 0.35 kat/g,1.48 ± 0.56 kat/g,0.20 ±0.07 kat/g and 0.18 ±0.06 kat/g in groups A,B,C and D,with a significant difference between the 4 groups( F =42.959,P =0.000).The mean Ca2 + content was respectively 5.20 ± 1.42 μg/mg,3.80 ± 1.40 μg/mg,0.19 ± 0.08 μg/mgand 0.20 ± 0.08 μg/mg in groups A,B,C and D,with a significant difference between the 4 groups ( F =39.242,P =0.000).Groups A and B were obviously higher than groups C and D and group A was obviously higher than group B in terms of ALP activity and Ca2+ content. Conclusion The rhBMP-2 loaded chitosan nanospheres prepared by ionic crosslinking method show a good property and obvious ectopic bone formation activity.

Magnesium alloy-and titanium alloy-made transoralpharyngeal atlantoaxial reduction plate systems for atlantoaxial dislocation: a three-dimensional finite element analysis / 中华创伤杂志

ObjectiveTo evaluate biomechanical properties of transoralpharyngeal atlantoaxial reduction plate (TARP) prepared from magnesium alloy and titanium alloy for the atlantoaxial dislocation by using three-dimensional finite element analysis and to exam the feasibility of using magnesium alloy for preparation of TARP system so as to provide a theoretical basis for clinical surgery.MethodsA patient with typical atlantoaxial fracture dislocation was involved in the study,and received thin CT scan with clinically used titanium alloy TARP system for obtaining DICOM image data.Three-dimensional finite element analysis software was imported to simulate magnesium alloy and titanium alloy TARP systems for reduction and fixation.Then,stress changes of the atlas,axis,internal fixators and C2/3 zygapophysial joints were determined with three-dimensional finite element analysis and analyzed statistically.Results ( 1 ) The finite element model of atlantoaxial dislocation reduction and fixation had lifelike outline and good geometric similarity.There were 53 586 nodes and 180 784 units.(2) During the simulation of head in neutral position,the stress concentration region was C2/3 zygapophysial joints followed by the anterior arch,posterior arch and lateral mass of atlas respectively,and C2 vertebral arch again.( 3 )Magnesium alloy and titanium alloy TARP systems showed significant difference in stress distribution (P ＜0.05).Conclusions(1)The atlantoaxial model established according to its structure information on CT can be used for biomechanical experiments.(2) For the treatment of atlantoaxial dislocation using the existing titanium TARP system,maintaining the integrity of anterior and posterior arch of atlas and confirming the bone fusion in lateral mass can better keep the stability of the atlantoaxis.After atlantoaxial fusion,the increased stress of the zygapophysial joints of the adjacent segments accelerates structural degeneration,which should be closely followed up.( 3 ) Magnesium alloy TARP system for fixation and reduction shows the fall in peak value of the stress concentration region,and improvement of the uniformity of stress distribution as compared with titanium alloy TARP.

Three-dimensional finite element analysis of anterior plate fixation for the treatment of sacroiliac joint dislocation☆ / 中国组织工程研究

BACKGROUND: Most reported biomechanical studies on sacroiliac joint injury and fixation use cadavers or artificial bone models to simulate the sacroiliac joint injury.OBJECTIVE: To analyze the vertical stability of anterior plate fixation for sacroiliac joint dislocation using three-dimensional finite element method. METHODS: The anterior plate fixation model of unilateral sacroiliac joint dislocation was constructed on the basis of the three-dimensional finite element model of a complete pelvis. An axial load of 500 N was applied on the model; the cloud pictures of stress, strain and displacement were obtained after calculation and compared with that of the complete pelvis under the same conditions.RESULTS AND CONCLUSION: Stress concentration occurred at the internal fixation system; the maximum stress was found at the screws near the injured sacroiliac joint, far greater than the maximum stress of the complete pelvis under the same condition. The maximum strain was found in the healthy sacroiliac joint; the fixed sacroiliac joint had no strain. The maximum displacement was found in the injured sacroiliac joint; it was about twice longer than the complete pelvis. These findings indicate that the vertical stability of pelvis is poor using anterior plate internal fixation treatment for sacroiliac joint dislocation; and stress concentration occurs at the screws and plates.

Three-dimensional reconstruction of finite element model of the cervical motion segment according to Chinese Digital Human CT data / 中国组织工程研究

BACKGROUND: Our team has built finite element dynamic bone models of different parts, but how to ensure the model’s precision and effectiveness, there still needs further study.OBJECTIVE: To provide accurate biomechanics model of Digital Human. METHODS: The CT data of Virtual Chinese Human --the male No.1 (VCH-M1) were imported into the MIMICS13.1 software authorized by the Materialise Company, and then the outcome document was entered into the ABAQUS6.7 software to perform finite element analysis. The result was observed and then the effectiveness of the models was tested. RESULTS AND CONCLUSION: The “.lis” document was chosen in the finite element analysis software ABAQUS6.7. Three dimension models of cervicalt were acquired. The model has 10 465 panel points and 52 752 units. It is verified that this model is effective. Results confirmed that the biomechanics model of Digital Human can be calculated for meeting the revolutionary requirement of the future digital medical science.

Osteogenesis study of compound antitumor coral hydroxyapatite in vivo / 中国组织工程研究

BACKGROUND: Compound antitumor coral hydroxyapatite (CCHA) has a good delayed-release and anti-tumor effect. However, whether the high-dose drug contained in the CCHA influences normal induction, conduction and growth of bone tissues at the implant site is unclear.OBJECTIVE: To establish an osteogenesis model of CCHA and to investigate the osteogensis effect and rule of self-made CCHA in vivo. METHODS: Implants of CCHA (20%CDDP-CHA w/w) and CHA(control, 0% CDDP w/w) were implanted into the metaphyseal holes of rabbit femur. X-rays and decalcified histological section of rabbit femoral bone with hematoxylin and eosin staining were used regularly to investigate the degradation of CCHA and CHA, and how bone tissues grow at the implant site. RESULTS AND CONCLUSION: After implantation, CHA crystals were faster than CCHA in connecting with surrounding bone tissues and forming bone bridges. The borderlines of implanted CHA became obscure in 4 weeks. Loose connective tissues were found in pores of the CHA and osteoblasts were growing on the surface. Bone tissues of the surrounding gradually grew into the CHA, finally repaired the bone defects. At the beginning of implantation, CCHA mainly inhibited the growth of surrounding tissues until 6-12 weeks later, normal bone tissues gradually grew into pores of CCHAs, and healed bone defects at 26 weeks. CCHA can inhibit the osteogenesis effects at early stage; however, it can achieve bone healing with surrounding bone defect ultimately.

Application of transoral atlantoaxial reduction plate Ⅲ in treatment of complicated atlantoaxial dislocation / 中华创伤杂志

Objective To evaluate the biomechanical characteristics and the clinical advantage of transoral atlantoaxial reduction plate(TARP)Ⅲ.Methods Design of TARP-Ⅲ was based on TARP-Ⅱ.The screw hole in the axis was moved 1-2 mm upwards and inwards in a plate which turned a vertebral screw into a pedicle screw or an articular process screw.A polyaxial self-lock ring and polyaxial guiding drill were added to the crew hole of the plate.Finally,the withdrawal resist ence force of the three axis screws was tested and TARP-Ⅲ was used in 44 patients with complicated irreducible atlantoaxial dislocation.The axis was fixed with the pedicle screw or the articular process screw.Results The maximum withdrawal resist ence force of the anterior pedicle screw,the articular process screw and the vertebral screw in the axis was(593.1 ± 97.8)N,(469.9 ± 73.3)N and(395.2 ± 75.1)N respectively,with statistical difference between groups among three fixation methods(P ＜ 0.05).All 44 patients were followed up for 5-38 months(average 18 months),which showed complete anatomic reduction in 36 patients and appropriate anatomic reduction in eight,with basic correction of the angles between the brain stem and the spinal cord and sufficient decompression of the spinal cord.The decompression rate of the cervical spinal cord was average 88.2% according to the Yin evaluating method of cervical cord decompression.The improvement rate of spinal cord function was average 76.6% according to Japanese Orthopaedic Association(JOA)score.Conclusion With the design of polyaxial self-lock mechanism,TARP-Ⅲ with the pedicle screw or the articular process screw surpasses TARP-Ⅱ with vertebral screw in aspect of biomechanics.

The finite element testing to the anterior atlantoaxial reduction plate system / 中国医师杂志

Objective To discuss the TARP (transoral pharyngeal atlanto axioal reduction plate,TARP) stress distribution under the condition of atlantoaxial dislocation treatment with the TARP system and explore the possible suggestion for the further innovation of the TARP system.Methods A fixed Finite Element model was constructed for transoral atlantoaxial reduction plate system based on the CT digital data of the China Digital Human NO.1.The internal structure changes and the stress distribution of TARP system under different loads were imitated and analyzed.Results The results showed that,after the fixation of the TARP system,different parts of the atlantoaxial had different stress under anteflexion,extension,lateral bending and rotation,the internal fixation parts located mainly at the mid-part of the TARP(0.159 × 108 ～0.732 × 108 Pa) and the root of the screw(0.214 × 109 ～0.958 × 109 Pa).Beside that,when using anteflexion,the stress mainly focused on the articular surface of the atlantoaxial(0.512 × 107 Pa).As for extension,the stress mainly focused on the part between the lateral mass and anterior arch (0.582 × 107 Pa).While lateral bending or rotation,the stress mainly focused on the axial screw nailing path (0.287 × 109 Pa and 0.241 × 109 Pa).Conclusions Although different parts of the TARP plate have different stress,its maximum stress lied in the root of the screw.The stress of plate mainly focused on the mid - part,no matter in what state of motion,therefore,the root of the screw and the mid-part of the plate bore the biggest stress,their strength decided the fatigue property of the TARP system.

Application of computer-aided technique in pelvic precise model preparation and individualized prosthesis implantation / 中国组织工程研究

BACKGROUND:Bone tumors around the Ⅱ section of pelvis are difficult to treat due to complicated anatomic structures.Using computer-aided technique,the excision range and prosthesis preparation can be individualized,which may obtain notable therapeutic efficacy in treating pelvic fractures in the clinic.OBJECTIVE:To discuss the application and the clinic effect of computer-aided technique in bone tumors therapy around the Ⅱsection of pelvis.METHODS:The pelvis model was generated with its CT data by rapid prototyping.Simulated bone resection and reconstruction were performed on the models.Then we designed surgical extension and made hemi-pelvic.Eight cases received resection of pelvic tumor and reconstruction based on computer-aided technique.RESULTS AND CONCLUSION:The resection of tumor and implantation of prosthesis were easily accessible.Two cases relapsed and 1 case loosened at 2 years after operation.According to Harris scoring criteria after total hip replacement,the scores of cases were well.The simulated resection and reconstruction of bone tumors around the Ⅱ section of pelvis based on computer-aided technique makes the operation easy and reconstruction precise,which produces good clinic results and offers a good promise for the application.

Length changes of knee lateral collateral ligaments following anterior cruciate ligament injury / 中国组织工程研究

BACKGROUND: Lateral collateral ligaments play an important role in maintaining knee stability.Motion reduction of knee joint can be realized and the changes laws of medial and lateral collateral ligaments' length after anterior cruciate ligament(ACL)injury during weight-bearing flexion can be obtained via 2D/3D image registration technique.OBJECTIVE: To study in vivo stability of length changes of the medial and lateral collateral ligaments of ACL injury knee during weight-bearing flexion.METHODS: Eight volunteers with unilateral ACL rupture and contralateral normal knees,was captured CT images and 2orthogonal images of the knee at 0,15°,30°,60°,and 90° of weight-bearing flexion.These orthogonal images were used to recreate the in vivo knee positions at each of the targeted flexion angles by the method of 2D/3D image registration.Through the bone insertion of medial and lateral collateral ligaments,the elongation changes of medial and lateral collateral ligaments were obtained.RESULTS AND CONCLUSION: At 0°,15° and 30°,the length of medial collateral ligament of ACL injury knees was longer than normal knees,but the lateral collateral ligaments length of ACL injury knee was shorter than that of normal knees.All the differences have statistical significances(P < 0.05).The findings demonstrated that,at 0°,15° and 30°,the medial collateral ligament length of ACL injury knees was longer than normal knees,but lateral collateral ligaments length of ACL injury knees was shorter than normal knees.