Analysis Of Influence Factors Of Postoperative Avascular Necrosis Of The Femoral Head After Femoral Neck Fracture In Children

Objective:To retrospectively study the clinical data of 28 children with femoral neck fracture,analyze the risk factors of postoperative avascular necrosis of femoral head(AVN).Methods:The clinical data of 28 children with femoral neck fracture treated from Jul 2014 to Jan 2019 in Pediatric Orthopaedic of Shandong University Qilu Hospital were retrospectively analyzed,including 21 males and 7 females,with an average age of 9.3 years(4.4-14 years).Fractures were classified by Delbet classification,4 cases of type ?,7 cases of type ?,15 cases of type ?,and 2 cases of type ?.The initial degree of displacement was according to the Garden classification.There were 16 cases in the non-obvious displacement group(Garden ?/? type)and 12 cases in the obvious displacement group(Garden ?/? type).All children were assisted with close or open reduction internal fixation.There were 6 cases of early operation(?24h)and 22 cases of delayed operation(>24h).There were 23 cases in the satisfactory reduction group and 5 cases in the unsatisfactory reduction group.All children were received standardized rehabilitation training after surgery.We had regular follow-up after surgery,and the follow-up was evaluated by the Ratliff classification standard.Age,fracture type,initial displacement degree,surgical timing,reduction quality and other factors are statistically analyzed with avascular necrosis of femoral head(AVN)respectively.Results:The average follow-up time of the 28 patients was 15.6 months(12-36 months).All the children healed.The healing rate was 100%.The average healing time was 3 months(2-6 months).According to the Ratliff evaluation criteria at the last follow-up,22 cases were excellent,3 were good,3 were poor,and the excellent and good rate was 89.3%.AVN appeared in 6 cases.There were 12 cases in the obvious displacement group,of which 6 cases had necrosis(50.0%),16 cases in the non-obvious displacement group,no necrosis occurred,and the difference was statistically significant(P=0.002);Necrosis occurred in 2 of 4 cases of Delbet ?fractures(50.0%),1 of 7 cases of Delbet ? fractures(14.3%),3 of 15cases of Delbet? fractures(20.0)%),2 cases of Delbet ? fractures did not occur necrosis,and the difference was not statistically significant(P=0.438);Early surgery was 6 cases without necrosis,delayed surgery was 22 cases,and 6 cases had necrosis(27.3%),and the difference was not statistically significant(P=0.289).There were 23 cases of satisfactory reduction group,including 2 cases of necrosis(8.7%),5 cases of unsatisfactory reduction group,including 4 cases of necrosis(80.0%),and the difference was statistically significant(P=0.003).We confirmed that the degree of initial displacement(P=0.045)and the quality of reduction(P=0.007)were the influential factors of avascular necrosis of the femoral head by multivariate Logistic regression analysis.There was no statistical difference in the occurrence of AVN in the age distribution(P=0.218).Conclusion:Postoperative avascular necrosis of femoral head after femoral neck fracture is related to the degree of initial displacement and the quality of reduction.The severe initial degree of displacement is more prone to avascular necrosis of femoral head,and the good reduction quality can reduce the incidence of AVN.The correlation between age,fracture type,surgical timing and avascular necrosis of the femoral head needs further study.