Avascular necrosis of the femoral head in children is also known as aseptic necrosis of the femoral head or Legg-Calve-Perthes disease.At present,generally acknowledged that it is a self-limited disease,its etiology is unclear,therapeutic methods are multiformity,and improper handling can lead to severe sequelae.The followings are the bases and clinics about avascular necrosis of the femoral head according to the recent reports and the author's research.

Objective To systematically evaluate the association between protein C and Legg -Calve -Perthes disease.Methods A literature research was performed through PubMed,Embase,Cochrane library,Web of Science,Chinese Biomedical Literature Database(CBM),China National Knowledge Infrastructure(CNKI)and Wan-fang Database from inception to February 201 6 on the association between protein C and Legg -Calve -Perthes disease.According to the Newcastle -Ottawa Scale(NOS)criteria,the quality of studies was evaluated and data were extracted.Meta -analysis was performed with Stata 1 1 .0 software.Results A total of 1 4 articles were included.Twelve articles on protein C and Legg -Calve -Perthes disease in the study group and the control group were compared.The results of Meta -analysis showed that there was no significant difference in protein C levels between the study group and the control group[odds radio(OR)=1 .41 ,95% confidence interval(CI)(0.87,2.28),P =0.1 47];five articles on protein C and the white race of Legg -Calve -Perthes disease between the study group and the control group were com-pared,The results of Meta -analysis showed that there was no significant difference in protein C levels between the whiteskin patients′group and the control group[OR =0.61 2,95%CI(1 .83,7.29),P =0.61 2];three articles on pro-tein C and the yellow race of Legg -Calve -Perthes disease between the study group and the control group were com-pared,and the results of Meta -analysis showed that there was no significant difference in protein C levels between the yellow skin patients group and the control group[OR =0.59,95%CI(0.05,6.72),P =0.080].Conclusion There is no significant correlation between protein C and Legg -Calve -Perthes disease.

Objective:To analyze of the clinical characteristics of unintentional injuries among urban and rural children in Suzhou city, aiming to provide a scientific basis for the prevention of unintentional injuries in the region.Methods:This study was a cross-sectional survey. Children in the outpatient and emergency departments of the Children′s Hospital of Soochow University were selected from March 2020 to February 2021, the gender, age, household registration, accident injury time, cause, place and educational intervention needs of the children were collected. The patients were grouped according to gender, ages, seasons and household registrations, the SPSS 21.0 statistical software package was used to analyze the clinical characteristics of accidental injury in children.Results:There were 32 561 children included in the study, including 20 180 males and 12 381 females. The percentage of boy increases with ages ( χ2 = 263.13, P<0.01). Most unintentional injuries occurred at home, 19 117 cases, accounted for 58.9% of total cases. The accidental injury composition ratio of urban children in 0-<1 year group (447 cases), 1-<3 year group (12 392 cases) and 3-<6 year group (9 381 cases) was higher than that of 6-<10 year group (6 931 cases) and 10-<14 year group (3 410 cases)( χ 2 values were 14.69-246.83, all P<0.01); fall was the most common cause of unintentional injuries in children, 12 404 cases, accounted for 38.1% of total cases. The percentage of unintentional injuries of 3-<6 year group in spring was higher than that of 0-<1 year group, 1-<3 year group, 6-<10 year group and 10-<14 year group; the percentage of unintentional injuries of 3-<6 year group in summer was higher than that of 0-<1 year group, 1-<3 year group, 10-<14 year group; the percentage of unintentional injuries of 0-<1 year group in antumn was higher than that of 1-<3 year group, 3-<6 group, 6-<10 year group; the percentage of unintentional injuries of 0-<1 year group in winter was higher than that of 1-<3 year group, 3-<6 year group, 6-<10 year group and 10-<14 year group ( χ2 values were 6.80-310.53, all P<0.01). Parents of 1-<3 year group had high demand for first aid knowledge, and parents of 0-<1 year group had high demand for first aid skills ( χ 2 values were 5.03-821.23, all P<0.01). Conclusions:The prevalence of unintentional injury in Suzhou city has age, season and regional characteristics. This study can provide a scientific basis for the prevention of unintentional injuries in the region.