A biomechanical investigation on the incorporation of cortical allograft in rabbit ulna defects

Objective:To explore the changes of biomechanical properties of cortical allograft in different mechanical environments.Methods:Cortical allograft was transplanted to each side of the midshaft diaphyseal ulna of each one of 40 rabbits.The left transplanted allograft underwent normal physiological load,while the right one underwent lower load.After animals were killed,specimens were taken for examination of bone mineral density,bone porosity and maximal three-point-bend breaking load.Results:The union strength of allograft-host bone junction was increased constantly;meanwhile,the internal creeping substitution led to an initial greater weakening of the cortical allograft itself and a later recovery of its strength.In comparison,the union strength of the normally loaded graft-host bone construct was significantly higher than that of the lower loaded side at the 8th and 16the week after transplantation.At the 16th week,there was greater bone strength in normally loaded graft than that in lower loaded graft.conclusions:The internal repair can lead to initial preater weakening of cortical allograft and later gradual recovery of its strength.The effect of physiological load can accelerate the improvement of the biomechanical properties of allograft.     

Interface contact profiles of a novel locking plate and its effect on fracture healing in goat

Objective： To evaluate the interface characteristics of the new-designed locking plate （LP） and limited contact-dynamic compression plate （LC-DCP） and compare the fracture healing between LP and LC-DCP in a goat tibia fracture model.
Methods： Eight-hole LP and LC-DCP were applied to fix fresh goat tibiae in a reproducible manner. The average pressure, force and interface contact area were calculated using Fuji prescale pressure sensitive film interposed among the plate and the bone and image analysis system, Eighthole LP and LC-DCP were applied to each tibia in a goat tibia fracture model. The fracture healing was evaluated by X-ray photography at postoperative 8 weeks. The goats were sacrificed at postoperative 12 weeks. Three-point bending test was conducted in the tibiae.
Results： The interface contact of LP system was smaller than that ofLC-DCP （P〈0.05）, while interface contact force of LP system was higher than that of LC-DCP （P〈0.05）. Radiographs revealed that the fracture line disappeared in the LP group, while the fracture line was visible in DCP group at postoperative 8 weeks. At postoperative 12 weeks, the bending strength and bending load of fractured tibia were higher in LP group than in DCP group, respectively.     

Precontoured buttress plate vs reconstruction plate for acetabulum posterior wall fractures: A biomechanical study

BACKGROUND The purpose of open reduction and internal fixation of acetabulum posterior wall fractures is to restore anatomical structure and stability of the hip joint, in order to start weight bearing as soon as possible and prevent hip arthrosis; restoration of the anatomy should preserve function of the joint as well. Although "special shaped precontoured plates" have been developed in recent years for surgical treatment of this region, studies comparing the traditional plates with the newly designed precontoured plates are lacking.AIM To evaluate the biomechanical properties of precontoured anatomic buttress and conventional curved reconstruction plates(CCRPs) for posterior wall acetabulum fracture treatment.METHODS Twelve pelvis models were created for testing plate treatment of fracture in the posterior wall of the acetabulum. These 12 pelvis models were used to create 24 hemipelvis models(experimental) by cutting from the sagittal plane and passing over the center of gravity, after which the posterior wall acetabular fractures(of similar type and size) were created. In these experimental models, the right acetabulum was fixed with a 5-hole CCRP, while the left was fixed with a precontoured anatomic buttress plate(PABP). Samples were placed through thetest device and were subjected to static load testing, with a constant testing velocity of 2 mm/min until the load reached 2.3 kN or the acetabular fixation failed. Dynamic tests were also performed with sinusoidal wave load, with a maximal load of 2.3 kN and a load ratio of 0.1.RESULTS The average stiffness values were 460.83 ± 95.47 N/mm for the PABP and 291.99± 118.58 N/mm for the 5-hole CCRP. The precontoured anatomic acetabulum buttress plates had significantly higher rigidity than the CCRPs(P = 0.022). There was a statistically significant difference between the unloaded and 2.3 kN-loaded values of AL(posterosuperior fracture line vertical to the ground surface) and CL(posteroinferior fracture line vertical to the ground surface) parameters for both the PABPs and the 5-hole CCRPs(P = 0.036 and P = 0.045, respectively).According to the static tests, the amount of total displacement was significantly less in the PABPs than in the CCRPs. Comparative analysis of the displacement in the BL(posterior wall fracture line horizontal to the ground) parameter yielded no statistically significant differences between the PABP and the 5-hole CCRPs(P= 0.261).CONCLUSION PABP provides more stable fixation in acetabulum posterior wall fractures than5-hole CCRP, allowing for proximal or distal fracture line screw application without reshaping.     

Effect of allograft compound vertebra on vertebral reconstruction in rabbits

Objective ： To study the effect of allograft compound vertebra on vertebral reconstruction in rabbits so as to provide biomechanical direction for manufacturing and selecting vertebral reconstruction materials. Methods： Twenty-five healthy New Zealand white rabbits were divided randomly into three groups： normal group （ Group A, n = 5 ） ,iliac bone graft group （ Group B, n = 10） and allograft compound vertebra group （ Group C, n = 10）. After C4 was resected, iliac bone implantation and allograft bone cage transplantation were fulfilled in Group B and Group C, respectively. Every 5 rabbits from Group B and Group C were selected to test the biomechanical strength and biological activity one and two months postoperatively. Results： No significant statistical difference was found between Group A and Group C one and two monthspostoperatively （ P 〉 0.05 ）. The biomechanical strength of Group B was much weaker than that of Group A and Group C one month postoperatively （P 〈 0.05 ）, but at two months postoperatively, no statistical difference was found among the three groups. The biological activity and vertebral moulding ability of Group C were better than those of Group B at one and two months postoperatively. Conclusions： Compound vertebra, which is made up of allograft cortical bone cage and autogenous cancellous bone, shows instantaneous and permanent biomechanical stability and biological activity, therefore, it is an ideal material for vertebral reconstruction.     

The influence of the interertebral disc on stress distribution of the thoracolumbar vertebrae under destructive load

Objectie:To compare the influence of normal and degenerative discs on stress distribution of the thoracolumbar vertebrae under destructive load,explore the biomechanical background and clinical meaning and provide theoretical basis for clinical diagnosis and treatment.Methods:A mechanical model of thoracolumbar motion segment of normal and degenerative discs was built with a three dimensional finite element method and three stresses of vertical compression,compressive flexion and distractive flexion were comparatively analyzed.Results:With vertical compression and compressive flexion loads,the thoracolumbar motion segment of the normal disc showed that the central part of the upper and lower end-plates of the vertebrae and the central part of the trabecular bone adjacent to the end-plate were lgaded with the most intensive stresses,meanwhile,the postero-lateral part of the annulus fibrosus was concentrated with stresses.Degeneratie disc showed that the stress distribution of the trabecular bone was relatively averaged,the stresses of the central part adjacent to the end-plate were low,while at the same time,the stresses of the peripheral part were elevated relatively.With distraction flexion load,the stresses of the cortex bone,trabecular bone,end-plate and annulus fibrosus of the thoracolumbar vertebrae of degenerative discs were low,neanwhile,the stresses of the posterior structure of the vertebral body were relatively elevated compared with that of normal discs.Conclusions:There is difference in influence between normal and degen erative discs on the stress distribution of the thoracolumbar vertebrae with destructive load.The transferring way of load is changed after disc degeneration.     

术前口服葡萄糖水对肠道手术围手术期胰岛素抵抗及血浆蛋白的影响

Objective To investigate the effects of oral intake of glucose solution before surgery on the pH at the lower esophagus,perioperative blood glucose level,and plasmic protein in patients undergoing radical resection for colorectal cancer.Methods Between January 2008 and December 2008,60 patients undergoing radical surgery for colorectal cancer were enrolled and randomized into three groups using the table of random digits.Four patients were withdrawn from the study.Patients in group A (n=19) were given 800 ml of 12.5% glucose solution for oral intake the night before surgery,and 200 ml two hours before surgery.Patients in group B (n=19) were given distilled water instead of glucose.Patients in group C (n=18) were asked to fast for 8-12 hours before operation.Combined general and epidural anesthesia was used.pH at the lower esophagus was monitored during intubation and extubation.Albumin,transferrin,prealbumin,insulin,and fasting blood glucose were measured before surgery and at postoperative day 1,3,and 7.Results pH at the lower esophagus was 8.05±0.43 in group A,7.98±0.41 in group B,and 7.94±0.41 in group C.There were no perioperative acid regurgitations (P＞0.05).Serum insulin in group A at postoperative day 1 was (16.32±16.11) μU/L,which was significantly lower than that in group B (30.65±41.74)μU/L and group C (34.01 ±52.91 ) μU/L.Log HOMA-IR in group A at postoperative day 1 was significantly lower than that in group B and group C (0.49±0.35 vs.0.59±0.56 and 0.60±0.63,P＜0.05).Transferrin in group C at postoperative day 3 and 7 was significantly lower than that in the other two groups,as was albumin at postoperative day 3(P＜0.05).Conclusion Oral liquid intake 2 hours before surgery is not associated with increased risk of regurgitation or aspiration during intubation and extubation,and may glucose solution intake reduce insulin resistance and protein degradation after colorectal surgery.     

Open reduction and internal fixation for displaced supracondylar fractures of the humerus in children with crossed K-wires via lateral approach

Objective： To assess the therapeutic results of open reduction and internal fixation with crossed K-wires via lateral approach for displaced supracondvlar fractures of the humerus in children. Methods： We prospectively followed 52 children who presented with Gartland type 3 displaced supraeondylar fractures of the humerus and were managed by open reduction and internal fixation with crossed K-wires via lateral approach.There were 37 male and 15 female patients; average age was 7.39 years. The most common mechanism of trauma was fall while playing （n=23）, followed by fall from height （n=20）, road traffic accidents （n-5） and fall from standing height （n=2）. In 2 cases, mode of injury was not available. The mean follow-up was 12 months and patients were assessed according to Flynn＇s criteria. Results： Lateral approach provided an excellent view of the lateral column between two nervous planes and enabled an anatomical reduction in all cases. Immobilizing the elbow at 90 degrees or more of flexion was not needed after cross K-wire fixation. Majority of patients regained full range of motion within 6 weeks of pin removal. Two patients had postoperative ulnar nerve injuries that resolved after pin removal. The common late complication of cubitus varus was not seen in any patient. Delayed presentation to the emergency department, repeated manipulations by bone setters and massage with edible oil were responsible for stiffness in 5 patients. Superficial pin tract infection was noted in 5 patients that resolved with dressings and antibiotics. No deep infection occurred. A detailed clinical examination and radiographic analysis was done at final follow-up. They included measurement of carrying angle and range of movements of both operated and normal sides, and radiographs of both upper limbs for comparison. According to Flynn＇s criteria, 90.4% patients showed satisfactory results. Conclusion： Lateral approach for open reduction and internal fixation of the widely-displaced supracondylar fract     

A retrospective study to compare the treatment outcomes with and without surgical navigation for fracture of the orbital wall

Purpose To evaluate the outcomes with and without aid of a computer-assisted surgical navigation system(CASNS)for treatment of unilateral orbital wall fracture(OWF).Methods Patients who came to our hospital for repairing unilateral traumatic OWF from 2014 to 2017 were included in this study.The patients were divided into the navigation group who accepted orbital wall reconstruction aided by CASNS and the conventional group.We evaluated the surgical precision in the navigation group by analyzing the difference between actual postoperative computed tomography data and preoperative virtual surgical plan through color order ratios.We also compared the duration of surgery,enophthalmos correction,restoration of orbital volumes,and improvement of clinical symptoms in both groups systemically.Quantitative data were presented as mean±SD.Significance was determined by the two-sample t-test using SPSS Version 19.0 A p<0.05 was considered statistically significant.Results Seventy patients with unilateral OWF were included in the study cohort.The mean difference between preoperative virtual planning and actual reconstruction outcome was(0.869±0.472)mm,which means the reconstruction result could match the navigation planning accurately.The mean duration of surgery in the navigation group was shorter than it is in the control group,but not significantly.Discrepancies between the reconstructed and unaffected orbital-cavity volume and eyeball projection in the navigation group were significantly less than that in the conventional group.One patient had remnant diplopia and two patients had enophthalmos after surgery in the navigation group;two patients had postoperative diplopia and four patients had postoperative enophthalmos in the conventional group.Conclusion Compare with the conventional treatment for OWF,the use of CASNS can provide a significantly better surgical precision,greater improvements in orbital-cavity volume and eyeball projection,and better clinical results,without increasing the duration of surgery.     

Biplane osteotomy and bone transport combined external locking plating for sequential treatment of massive tibial bone defects北大核心CSCD

Objective To evaluate biplane osteotomy and bone transport combined external locking plating for sequential treatment of massive tibial bone defects. Methods Twenty-eight patients with massive tibial bone defects were reviewed who had been treated at Department of Repair and Reconstruction, Wuhan Puai Hospital from October 2013 to October 2019. They were divided into a bone transport group and a combined bone transport group (bone transport combined external locking plating) according to their surgical methods. In the bone transport group of 14 cases, there were 10 males and 4 females with an age of (38. 6 ±3. 2) years and a bone defect of (8. 0 ± 0. 5) cm; in the combined bone transport group of 14 cases, there were 9 males and 5 females with an age of (39. 1 ± 3. 9) years and a bone defect of (8. 3 ± 0. 3) cm. The time for wearing external fixator, fracture healing time, dock-in-site healing time, postoperative function assessment and complications were observed and compared between the 2 groups. Results There was no significant difference between the 2 groups in their preoperative general data, showing they were comparable (P > 0. 05). The bone transport group were followed up for 12 to 28 months (average, 18. 4 months) and the combined bone transport group for 12 to 26 months (average, 16. 8 months) . The time for wearing external fixator in the combined bone transport group [(8.4±0.7) months] was significantly shorter than that [(13.3±1.4) months ] in the bone transport group (P< 0. 05). No significant difference was observed between the 2 groups in either the fracture healing time [ (8. 4 土1.3) months versus (7. 4 ± 1. 2) months] or the dock-in-site healing time [(210. 2 ±9.1) months versus (206. 2 ± 9. 8) months ] (P > 0. 05). By the Association for the Study and Application of the Method of Ilizarov (ASAMI) scoring, the bone healing was excellent in 6, good in 5 and fair in 3 cases in the bone transport group while excellent in 8, good in 4 and fair in 2 cases in the combined bone transport group, showing no significant difference between the 2 groups in the excellent to good rate (P > 0. 05). By the postoperative functional assessment of the lower extremity, there were 7 excellent, 3 good, 3 fair and one poor cases in the bone transport group while 8 excellent, 5 good and one poor cases in the combined bone transport group, showing no significant difference between the 2 groups in the excellent to good rate (P > 0. 05). In the bone transport group, there were 3 cases of pin track infection, one case of dock-in-site nonunion, 2 cases of poor alignment of lower extremities, 2 cases of skin depression, one case of nail loosening, 5 cases of joint stiffness and 3 cases of delayed union of the distracted bone; in the combined bone transport group, there were one case of pin track infection, 2 cases of poor alignment of lower extremities, 3 cases of skin depression, 3 cases of joint stiffness, 2 cases of delayed union of the distracted bone and one case of refracture. Conclusion In the sequential treatment of massive tibial bone defects, biplane osteotomy and bone transport combined external locking plating can reduce the time for wearing external fixator and increase the satisfaction of patients. © The Author(s) 2022.     

Three-dimensional printing combined with open reduction and internal fixation versus open reduction and internal fixation in the treatment of acetabular fractures: A systematic review and meta-analysis

Purpose: This meta-analysis compared the clinical outcome of three-dimensional (3D) printing combined with open reduction and internal fixation (ORIF) to traditional ORIF in the treatment of acetabular fractures. Methods: We searched the Cochrane Library, PubMed, Embase, VIP database, CNKI, and Wanfang database with keywords “acetabular fracture”, “3D printing”, “three-dimensional printing”, “open reduction and internal fixation”, “Acetabulum”, “Acetabula” from January 2000 to March 2020. Two reviewers independently selected articles, extracted data, assessed the quality evidence and risk bias of included trials using the Cochrane Collaboration’s tools and/or NewcastleeOttawa scale. When the two analysts had different opinions, they would ask the third analyst for opinion. Randomized controlled trials or retrospective comparative studies of 3D printing combined with ORIF (3D printing group) versus traditional ORIF (conventional group) in the treatment of acetabular fractures were selected. The data of operation time, intraoperative blood loss, intraoperative fluoroscopy times, incidence of complications, excellent and good rate of Matta score for reduction, and excellent and good rate of hip function score were extracted. Stata14.0 statistical software was used for data analysis. Results: Altogether 9 articles were selected, including 5 randomized controlled trials and 4 retrospective studies. A total of 467 patients were analyzed, 250 in the conventional group, and 217 in the 3D printing group. The operation time in the 3D printing group was less than that in the conventional group and the difference was statistically significant (standardized mean difference (SMD) = 1.19, 95% CI: 1.55 to 0.82, p < 0.05). The intraoperative bleeding volume of the 3D printing group was significantly lower than that of the conventional group (SMD = 1.08, 95% CI: 1.65 to 0.51, p < 0.05). The fluoroscopy times were less in the 3D printing group than in the conventional group and the difference was statistically significant (SMD = 1.64, 95% CI: 2.35 to 0.93, p < 0.05). The total incidence of complications in the 3D printing group was significantly lower than that in the conventional group (OR = 0.43, 95% CI: 0.24-0.79, p < 0.05). There was no significant difference in the excellent and good rate of Matta score for reduction between the two groups (OR = 0.60, 95% CI: 0.34-1.06, p > 0.05). There was no significant difference in the excellent and good rate of hip function score at the end of postoperative follow-up between the two groups (OR = 0.84, 95% CI: 0.46-1.56, p > 0.05), but the follow-up time varies from 6 months to 40 months. Conclusion: Compared with traditional ORIF, 3D printing combined with ORIF has certain advantages in terms that 3D printing not only helps surgeons to understand acetabular fractures more intuitively, but also effectively reduces operation time, intraoperative blood loss, intraoperative fluoroscopy times, and postoperative complications. However, there were no significant differences in the excellent and good rate of Matta score for reduction and the excellent and good rate of hip function score at the end of follow-up.     

Faculty of Anaesthetists of the Royal College of Surgeons of Ireland

The Faculty of Anaesthetists of the Royal College of Surgeons of England, 35–43 Lincoln's Inn Fields, London WC2A 3PN. Telephone: 01-405 3474.     

深圳市某两所小学流行性腮腺炎突发疫情的流行病学分析

目的：通过对深圳市某两所小学发生的流行性腮腺炎突发疫情的流行病学特点及差异性进行分析,为制定科学、高效的防控策略提供科学依据。方法2013年5～7月深圳市大鹏新区某两所小学爆发流行性腮腺炎,以学校为整体研究对象,分别标记为学校A（24个班,学生1210例）和学校B（27个班,学生1274例）,对比两所小学的疫情流行病学差异性。结果分析发现,学校A流行性腮腺炎发病率为4.30%,发病班级所占比54.17%,均较学校B1.73%和29.63%高,对比差异有统计学意义（P＜0.05）;分析显示学校A学生出现疫病平均年龄为（11.2±1.1）岁,较学校B（9.34±1.0）岁,对比差异明显（P＜0.05）;且两组疫病患儿在接种疫苗率对比上差异无统计学意义（P＞0.05）;但疫情发生时,学校B疫苗紧急接种率明显高于学校A,对比差异有统计学意义（P＜0.05）。结论小学作为流行性腮腺炎爆发的主要场所之一,疫病爆发高峰季节前,针对易感染人群给予相应的疫苗接种等预防控制措施,同时加强流行性腮腺炎的监测,对于降低感染人群数量,减轻、遏制疫情有着积极的意义,值得相关防控部门重视。