BACKGROUND:For non-traumatic osteonecrosis of the femoral head,if the femoral head collapses,it will have a great impact on the normal life of the patients.Thus,it is necessary to use an appropriate way to evaluate the risk of femoral head collapse and then to take targeted measures to delay the process of femoral head collapse. OBJECTIVE:To analyze the natural course of early osteonecrosis of the femoral head(without collapse)under different locations of necrotic lesions. METHODS:121 patients(191 hips)with early non-traumatic osteonecrosis of the femoral head who were treated in the Outpatient Department of Honghui Hospital Affiliated to Xi'an Jiaotong University from October 2016 to October 2017 were enrolled in this study.The clinical data of all patients were followed up for 5 years to observe the collapse of osteonecrosis of the femoral head and the risk coefficient of femoral head collapse among different JIC types.The collapse rate of osteonecrosis of the femoral head was calculated during the follow-up. RESULTS AND CONCLUSION:(1)A total of 191 hips were included in this study.The femoral head collapsed in 86 hips during follow-up,with a total collapse rate of 45.0%.Among the influencing factors,age,ARCO stage and JIC classification were the main influencing factors of femoral head collapse(P<0.05),but body mass index,sex,incidence side and pathogenic factors were not the main influencing factors(P>0.05).(2)Among 191 hips,in JIC classification,the total collapse rates of type A,type B,type C1 and type C2 were 11.1%(2/18),30.2%(16/53),52.4%(43/82),and 65.8%(25/38),respectively.There were significant differences in the total collapse rate of the femoral head among all types(P<0.05).The collapse risk results showed that the collapse risk of type B,type C1 and type C2 was 2.41,5.22 and 7.89 times higher than that of type A,respectively.(3)Both JIC classification and ARCO stage were correlated with femoral head collapse(P<0.01).There was no significant difference in the collapse rate of the femoral head among all JIC types in ARCO I stage hips(P>0.05).In the hips with ARCO II stage,the collapse rates of the femoral head of JIC types A,B,C1 and C2 were 1.2%,19.5%,50.0%and 29.3%,respectively,and there were significant differences in the collapse rates among different types(P<0.05).(4)During follow-up,the collapse rates of the femoral head in the first to fifth years were 29.3%,7.9%,4.7%,2.6%and 0.5%,respectively.(5)Results showed that for early non-traumatic osteonecrosis of the femoral head,the risk of collapse of osteonecrosis of the femoral head is high within one year,and the location of the focus of osteonecrosis affects the risk of collapse of the femoral head.The effect of the location of the focus on the prognosis of the disease should be considered in clinical treatment.

BACKGROUND:Osteonecrosis of the femoral head is one of the refractory diseases in orthopedic diseases.The natural collapse course of osteonecrosis of the femoral head under different stages and types affects the progression and prognosis of the disease. OBJECTIVE:To explore the progression of natural collapse within 5 years in patients under the different classifications of China-Japan Friendship Hospital(CJFH)with stage Ⅱ osteonecrosis of the International Association for Research Circulation Osseous(ARCO),and to analyze the collapse rate and collapse risk of the femoral head under the different classifications of CJFH. METHODS:A retrospective study was performed to select patients diagnosed with ARCO Ⅱ stage osteonecrosis of the femoral head without collapse in the Honghui Hospital Affiliated to Xi'an Jiaotong University from October 2016 to October 2017.According to whether it collapsed,the number of hips was divided into the collapse group(n=82)and the non-collapsed group(n=70).The collapse risk of patients with osteonecrosis of the femoral head under different CJFH classifications,as well as the collapse time,number of collapses,and collapse rate within 5 years were counted,and then the Kaplan-Meier survival curve of the femoral head under different classification of CJFH was plotted. RESULTS AND CONCLUSION:(1)A total of 97 patients with 152 hips were enrolled,and 82 hips collapsed during the follow-up period,with a total collapse rate of 53.9%,of which the collapse rates of M type,C type,L1 type,L2 type,and L3 type were 0.0%,36.7%,51.4%,72.2%,and 77.8%,respectively,and the comparison between the groups was statistically significant(P<0.05).(2)In terms of collapse risk,the collapse risk of L1 type was 1.704 times that of C-type(P>0.05),while the collapse risks of L2 type and L3 type were 3.866 times and 6.423 times that of C type(P<0.05),respectively.(3)In terms of the Kaplan-Meier survival curve,the median survival time of the femoral head of ARCO Ⅱ stage patients was 3 years,with a 95%confidence interval of 2.885-3.471 years,and the survival rates of the femoral head at the first,third and fifth years were 65.1%(99/152),50.7%(77/152),and 46.1%(70/152),respectively.(4)These findings conclude that different CJFH classifications affect the collapse rate of ARCO Ⅱ stage osteonecrosis of the femoral head patients,among which L3 type patients have the highest collapse rate,followed by L2 type and L1 type patients;C type patients have a lower collapse rate,and M type patients do not collapse,which indicates that the preservation of the lateral column of the femoral head is of great significance for the natural collapse course of osteonecrosis of the femoral head.