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.

BACKGROUND:Magnetic resonance imaging is the gold standard for the diagnosis of osteonecrosis of femoral head,and previous methods of predicting osteonecrosis of femoral head collapse based on magnetic resonance images mostly require the combined assessment of coronal and sagittal images.However,osteonecrosis of femoral head tends to occur bilaterally,most hospitals perform bilateral hip magnetic resonance imaging scans during clinical examinations,but the bilateral hip scans can only view coronal and cross-sectional images,and it is difficult to obtain sagittal images,which affects the assessment of the risk of collapse.Therefore,it is of clinical value to establish a method to assess the risk of early osteonecrosis of femoral head collapse by applying the images that can be obtained after bilateral hip magnetic resonance scanning. OBJECTIVE:To establish a method of applying coronal and cross-sectional images of bilateral hip magnetic resonance imaging to assess the risk of osteonecrosis of femoral head collapse. METHODS:The medical records of 111 patients(181 hips)with early-stage osteonecrosis of femoral head diagnosed at the outpatient clinic of Honghui Hospital Affiliated to Xi'an Jiaotong University from October 2017 to October 2019 were retrospectively analyzed.They were categorized into collapsed and non-collapsed groups according to the femoral head collapse at the final follow-up,with 69 hips in the collapsed group and 112 hips in the non-collapsed group.The angle of necrotic range on the images of median coronal plane,transverse plane or one level above and below it was measured on the magnetic resonance imaging system.The sum of the two angles of necrotic angle on the coronal and transverse planes was used as the combined necrotic angle.The average of the three combined necrotic angles of each hip was taken to get the average combined necrotic angle of each hip.Finally,the correlation between the three combined necrotic angles and the average combined necrotic angle with the collapse of osteonecrosis of femoral head was analyzed,and the specificity and sensitivity of the four combined necrotic angles in predicting collapse were evaluated by using receiver operating characteristic curves. RESULTS AND CONCLUSION:(1)Totally 69 hips(38.1%)had femoral head collapse at the last follow-up and were included in the collapsed group;112 hips(61.9%)did not have progression of collapse and were included in the non-collapsed group.(2)The difference between the collapsed group and the non-collapsed group in terms of Association Research Circulation Osseous(ARCO)stage was significant(P<0.001).The difference in age,body mass index,follow-up time,gender distribution,side of onset,and causative factors was not significant(P>0.05).(3)The results of independent samples t-test suggested that all four combined necrotic angles were significantly correlated with collapse(P<0.000 1);and the differences in combined necrotic angles between the collapsed group and the non-collapsed group of ARCO stage I and the two groups of ARCO stage II were all significant(P<0.000 1).(4)In the analysis of the receiver operating characteristic,the area under the curve of the average combined necrotic angle was greater than that of the combined necrotic angle on the lower level of the median,the middle level,and the upper level of the median.(5)The average combined necrotic angle had a higher accuracy in the prediction of collapse than the lower level of the median,the middle level,and the upper level of the combined necrotic angle.(6)It is concluded that the accuracy of the average combined necrotic angle in predicting the risk of osteonecrosis of femoral head collapse is higher,and the clinical practicability is stronger,so we can consider using this method to predict the risk of osteonecrosis of femoral head collapse.