Objective:Traumatic heterotopic ossification is the formation of extra-skeletal bone within soft tissues or joints after trauma. Injury factors induce many types of precursor cells to participate in this process. Many cytokines such as bone morphogenetic proteins, hypoxia inducible factor 1-α, inflammation factors and fibrin, can influence this process. Formation of heterotopic ossification often leads to the limitation of limb function and pain. However, prevention and treatment of heterotopic ossification often lead to bone nonunion and high recurrence rate. To find a treatment that can inhibit the formation of heterotopic ossification without affecting fracture healing has become a concern of clinicians. It is necessary to explore the formation mechanism of heterotopic ossification and find effective and safe methods. The authors document the cellular and molecular mechanisms involved in formation of traumatic heterotopic ossification for better understanding the factors affecting the formation of heterotopic ossification so as to provide references for new treatment methods.

Neurologic heterotopic ossification (NHO) is a pathological phenomenon that involves the formation of ectopic bone in soft tissues, which is associated with central nervous system injury. NHO may cause severe complications such as disorder of limb's activity, severe pain, and skin ulcer. The pathogenesis of NHO is not clear. In the past decades, there's better understanding of NHO pathogenesis, and potential predictive and therapeutic targets were found. The authors overview the NHO pathogenesis based on osteogenic factors, osteogenic precursor cells and microenvironments, soas to provide references for clinical diagnosis and treatment.

SUMMARY Peripheral nerve defects are still a major challenge in clinical practice,and the most com-monly used method of treatment for peripheral nerve defects is nerve transplantation,which has certain limitations and shortcomings,so new repair methods and techniques are needed.The peripheral nerve is elongated in limb lengthening surgery without injury,from which we got inspirations and proposed a new method to repair peripheral nerve defects:peripheral nerve elongation.The peripheral nerve could be elongated by a certain percent,but the physiological change and the maximum elongation range were still unknown.This study discussed the endurance,the physiological and pathological change of peripheral nerve elongation in detail,and got a lot of useful data.First,we developed peripheral nerve extender which could match the slow and even extension of peripheral nerve.Then,our animal experiment result confirmed that the peripheral nerve had better endurance for chronic elongation than that of acute elonga-tion and cleared the extensibility of peripheral nerve and the range of repair for peripheral nerve defects. Our result also revealed the histological basis and changed the rule for pathological physiology of peri-pheral nerve elongation:the most important structure foundation of peripheral nerve elongation was Fon-tana band,which was the coiling of nerve fibers under the epineurium,so peripheral nerve could be stretched for 8.5% -10.0% without injury because of the Fontana band.We confirmed that peripheral nerve extending technology could have the same repair effect as traditional nerve transplantation through animal experiments.Finally,we compared the clinical outcomes between nerve elongation and perfor-mance of the conventional method in the repair of short-distance transection injuries in human elbows, and the post-operative follow-up results demonstrated that early neurological function recovery was better in the nerve elongation group than in the conventional group.On the whole,all of these experimental re-sults revealed the physiological phenomenon of peripheral nerve elongation,and described the physiologi-cal change and stretch range in detail.The systematic research results have filled the blank in this field, which is very helpful for clinical limb lengthening surgery,the design of elongation surgery and the evalu-ation of the peripheral nerve stretch injury.Peripheral nerve elongation will become an innovative treat-ment technology in repairing peripheral nerve defects.

SUMMARY Trauma is a global social problem, with the number of deaths up to 5.8 million all over the world annually.Currently, severe trauma has become the first cause of death in young adults in China. Nowadays, there are many problems in the trauma rescue system, including long pre-hospital transfer pe-riod , several secondary transfers, no information exchange between pre-hospital and in-hospital care, and the poor integrated treatment, which results in the situation that the overall treatment level of severe trau -ma in China is relatively low.In order to solve these problems, we carried out the research and promotion of severe trauma rescue standard, involving completing severe trauma information database , providing lo-cal rescue medical workers with standard training , and building up the information system for the linkage and warning of severe trauma.In addition, we developed and promoted the new standard system for se -vere trauma in 15cities with 124 medical centers.Due to our research, the treatment ability of severe trauma in the pilot areas was enhanced, and the mortality and morbidity of severe trauma were reduced significantly.To sum up, we had got the expected results after implementing the project .

Objective: To compare efficacies and complications of total hip arthroplasty ( THA ) with subtrochanteric osteotomy for treating patients with Hartofilakidis types C1 and C2 developmental dyspla-sia of the hip ( DDH) .Methods:Retrospective analysis was performed in 32 patients with DDH who un-derwent THA.These patients were divided into two groups according to Hartofilakidis classification, 17 patients in type C1 and 15 in type C2.Their HSS and WOMAC scores, leg length discrepancy (LLD), hip joint image data and complications were evaluated.Results:HSS scores in type C1 was changed from preoperative 43.7 ±4.6 to postoperative 87.2 ±7.1 (P<0.001), together with WOMAC scores 43.6 ± 4.3 to 87.5 ±6.7 (P<0.001).HSS scores in type C2 was changed from preoperative 44.4 ±5.4 to postoperative 86.5 ±8.0 (P<0.001), together with WOMAC scores 44.1 ±4.1 to 86.7 ±8.1 (P<0.001).Four cases in type C2 and one case in type C1 presented intraoperative fracture which all healed during the postoperative follow-up.The postoperative X-ray films showed that the joint prosthesis location was satisfactory, the surrounding bone was not dissolved and the bone at femur osteotomy site healed with no infection.Conclusion:For unilateral high dislocation DDH patients, THA with femur osteotomy can be effective and safe.No significant differences were found between types C1 and C2, however intraoper-ative fracture in type C2 should be paid attention to.

Objective:To identify the characteristics and risk factors of the refractures after percuta-neous kyphoplasty ( PKP) and percutaneous vertebroplasty ( PVP) .Methods:A retrospective analysis of 148 patients who had undergone PKP or PVP between March 2006 and October 2013 inPeking University People’ s Hospital was conducted.In the study, 29 patients with 42 refractured vertebra and 119 patients without refracture were included.All the patients were observed for a time of (34.4 ±26.8) months. Clinical, imaging and procedure related factors ( gender, age, height, weight, body mass index, the level of the injured vertebra, the time interval between the procedure and the refracture, the level of the refractured vertebra, the bone cement volume injected, performed PKP or PVP,performed unilateral or bilateral, the percentage of anterior vertebral height restoration, the correction of the Cobb angle, cement diffusion, bone mineral density, presence or absence of diabetes mellitus, history of fractures of the whole body, anti-osteoporosis treatment, cement leakage) for each group were analyzed by Cox propor-tional hazards regression analysis.Results:Of all the patients,16 (55.17%, 16/29) had refractures in the adjacent vertebra, and 13 (44.83%, 13/29) had refractures in the nonadjacent vertebra.Refrac-tures within 3 months accounted for 31.03%(9/29) of all the refractures, and within 1 year accounted for 55.17%(16/29).Both older age (P=0.027, HR=1.051, 95%CI=1.006-1.098) and a his-tory of fractures of the whole body (P=0.012, HR=0.386, 95%CI=0.184-0.812) were statistical-ly significant as the independent risk factors for predicting refractures.Others were not associated with re-fractures ( P>0.05) .Conclusion:Older age and a history of fractures of the whole body are the inde-pendent risk factors of the refractures after PKP and PVP.The mechanism of the refractures after PKP and PVP is mainly the natural development of osteoporosis.

Objective To analyze the injury characteristics in 2004-2009 road traffic accidents (RTAS) of 0-25 years old adolescents treated in Beijing 120 Emergency Center so as to provide scientific basis for making effective measures in prevention and control of RTAs. Methods The data of all the adolescents with traffic injuries treated in Beijing 120 Medical Emergency Center were collected for a retrospective analysis on sex,age,traffic injury time,wound regions,injury characteristics and death condition of the injured adolescents. Results( 1 ) There were 17 232 injuries and 259 deaths according to the traffic reports from 2004 to 2009. Among the total injury cases,there were 4 229 cases of 0-25 years old adolescents (24.5％),at (20.13 ± 4.43 ) years of age.The injury number showed a significant rising trend with the increase of age and the injury number of 20 years old group were obvious more than that of other age groups.(2) There were 2 252 males and 1 677 females,with ratio of males to females for 1.5:1 ( P ＜ 0.05 ).( 3 ) Total number of patients was decreased yearly.The high incidence of adolescent RTAs could be seen in September,October and May in one year; Friday,Saturday and Sunday in one week; and between 8:00 am and 11:00 pm in one day.The low incidence of adolescent RTAs could be seen in Tuesday in one week,and 3:00-6:00 am in one day (P ＜0.05).(4) Cases of limb and arthrosis wounds (53.4％) were more than those of head and neck wounds (35％).Most of the cases were pedestrians (49.1％ ).(5) There were 38 deaths,including 28 males and 10 females,at ageof (19.29 ± 5.30) years.The death were mainly resulted from craniocerebral injuries (87％),which mainly concentrated in July ( 13.2％ ) and August ( 15.8％ ). Conclusions The present condition ofadolescent traffic injuries is not good enough.We should strengthen traffic security education,increase executive powers in the traffic rush and promote cooperation and communication in pre-hospital emergency,as may be beneficial for decreasing adolescent RTA.

ObjectiveTo investigate the epidemiological features and risk factors of road traffic injury in Beijing.MethodsData of road traffic injuries of Beijing Changping Hospital in 2010 was collected for statistical analysis of the epidemiological features. ResultsA total of 990 cases of road traffic injuries were treated in Beijing Changping Hospital in 2010,with a male/female ratio of 2.57:1 and at average age of 45 yeats.There were 21 cases aged ＜ 18 years,703 cases aged 18-55 years and 266 cases aged ≥56 years.Self-employed individuals and fanning production staffs were the risky population that were easily subjected to road traffic injuries.Summer and autumn were the accident-prone seasons.The most common injury site was the lower limbs,next with the neck and head.The hospital stay was mainly in a range of 5-10 days (12.8 days on average).ConclusionsMale self-employed individuals and agricultural producers are the high-risk groups of road traffie accidents in the area,where shows a high occurrence of road traffic accidents in the summer and autumn.Thereby,traffic safety education and prevention-control measures based on these characteristics should be carried out to effectively reduce the number and severity of the local traffic injuries.

Objective To describe the rule of the phenotypic changes of schwann cells after peripheral nerve injury.Methods All experiments were performed on 18 male SD rats.Right midsciatic nerves were cut and were repaired by epineurium suture.At selected time points after injury(1 week,2 weeks,3weeks;n=6 rats for each time point),the proximal and distal sciatic nerve stumps(approximately a 2 mm length of nerve to the injured tip)were removed for detecting the expressions of GFAP,Sox2 and Krox20 by immunofluorescence methods. Results After sciatic nerve transection.there was expansion in the population of GFAP-labeled Schwann cells both in the proximal and distal stumps,and those expression reached the peak near to 7 d.Sox2 was neural stem cell markers and there was no Sox2-expressed cells stumps after nerve injury.And Krox20 positive Schwann cells continuously decreased in the first week,then had increased. Conclusion The differentiated stage of Schwann cells during peripheral nerve repair can be detected by using immunolabeling,and the observation above may be beneficial to find methods in improving nerve regeneration.

Objective To investigate the amplifying results of repairing degenerated distal receptor nerves with normal proximal donor nerves.Methods The study was carried out on 12 adult male SD rats that randomly derided into degeneration group and control group.The distal tibial nerve stumps as receptor nerve were denervated for 8 weeks before cross-sutured with partial freshly transected proximal common peroneal nerve stumps in the degeneration group,while in the control group,freshly transected distal tibial nerve stumps were sutured with partial freshly cut proximal common peroneal nerve stumps.The motor nerve conduction (MCV),muscle rigidity contraction force were measured,the histological examinations were carried out and the numbers of myelinated axons were calculated 3 months after the operation.Results The degeneration group showed a poorer regeneration capacity than the control group (P＜0.05).The MCV were (16.992 ± 3.737) m/s,(23.092 ± 2.788) m/s respectively;The ratio of muscle force were (39.642 ±5.865)% and (71.098± 6.778)% respectively.The regenerated myelinated nerve fiber number were 1718.2± 282.0 and 3340.0 ± 506.5 respectively in degeneration group and control group.The amplifying ratio of the degeneration group and control group were 1.581 ± 0.329 and 3.098 ± 0.642.Conclusion The amplifying results of repairing the degenerated nerves are poorer than repairing the freshly injury distal nerves with the freshly transected proximal donor nerves,the results demonstrate a progressive inability of chronically degeneration of the distal nerve to support axonai regeneration.