Collapse Prediction Of Osteonecrosis Of The Frmoral Head Based On Proximal Sclerosis Proportions And Its Relationship With Traditionai Chinese Medicine Constitutions

Osteonecrosis of the Femoral Head (ONFH) is a common refractory disease in the field of orthopedics. It is estimated that there are5million to7.5million ONFH patients who need treating in our country. And the new cases are150,000-300,000annually. Without proper treatment, about80%of ONFH will develop to the collapse of the femoral head in1to4years and87%of them require artificial joint replacement in2years. Because of the limited life of artificial joints, quite a number of young patients have to face the second or even more times hip arthroplasty, which cause great pain to the patients and pose a heavy burden on the patients’families and society. Therefore, early treatment is essential to prevent femoral head collapse. There are plenty of methods to predict collapse of ONFH. However, all of them have their limitations and cannot fully meet the clinical needs. In clinical practice, we found that proximal sclerosis could play a role in preventing the collapse of the femoral head. This study based on proximal sclerosis proportions to predict the collapse of ONFH and explore its relationship with TCM constitutions. It can provide new methods for predicting the collapse of ONFH and new ideas for TCM treatment of ONFH.Objective:1. To provide theoretical basis for the application of proximal sclerosis proportions to predict the collapse of ONFH, finite element analysis was used to evaluate the mechanical effects of proximal sclerosis on stress on the femoral head and necrotic tissue.2. To explore the relationship between proportions of proximal sclerosis and the collapse of ONFH and create the reference value of proximal sclerosis proportions to predict the prognosis of ONFH.3. To analyze the effects of TCM constitutions on repair capacity of ONFH and provide new views for TCM treatment of ONFH, the relationship between ONFH TCM constitutions and the proportions of proximal sclerosis were explored.Methods:1. The finite element analysis of the mechanical effects of proximal sclerosis on the femoral head and necrotic tissue:The study utilized the CT (computed tomography) of both hips to generate the three-dimensional finite element models with different proportions of proximal sclerosis (0,30,50, and100%). Using a negative-directional mechanical load of400N, total deformation, deformation in the negative Z-axial direction (the direction of longitudinal compression), maximum principal stress, minimum principal stress, and contact pressure on the necrotic tissue were evaluated. Deformation and stress distribution of the femoral head and necrotic tissue with different proportions of proximal sclerosis were observed.2. Reference value establishment of proximal sclerosis proportion to predict the prognosis of ONFH:101cases (including170hips) were collected from out-patient clinic of orthopedic of Guang’anmen hospital of China Academy of Chinese Medical Science. Each case took CT examinations of the pelvis. All the patients filtered into the inclusion and exclusion criteria. There were three layers to measure the proximal sclerosis proportions, including the maximum necrotic area level on coronal CT images and the before and after levels. Using CAD software to estimate the proximal sclerosis proportions. The data were compared in collapse group and non-collapse group. Then draw ROC curve to obtain the reference value of collapse diagnosis of ONFH.3. Research of the correlation between ONFH TCM constitutions and the proportion of proximal sclerosis:96cases that the TCM constitutions conformed to yang-deficiency and (or) dampness-heat (or) and blood-stasis constitutions were collected from out-patient clinic of orthopedic of Guang’anmen hospital of China Academy of Chinese Medical Science. Each case took CT examinations of the pelvis. There were three layers to measure the proximal sclerosis proportions, including the maximum necrotic area level on coronal CT images and the before and after levels. Using CAD software to estimate the proximal sclerosis proportions. Analyzed the differences between TCM constitutions.Results:1. The finite element analysis of the mechanical effects of proximal sclerosis on the femoral head and necrotic tissue:For0,30,50, and100%rim sclerosis, the total femoral head deformations were0.207,0.205,0.202, and0.196mm, deformation of the negative Z-axis were-0.134,-0.132,-0.130, and-0.126mm,the maximum principal stresses in compression were-0.361,-0.349,-0.304, and-0.301MPa, the minimum principal stresses in compression were-0.862,-0.292,-0.274, and-0.252MPa and contact pressure were0.41,0.35,0.34, and0.31MPa, With the increasing proportion of proximal rim sclerosis, all the measurement indexes decreased.2. Reference value establishment of proximal sclerosis proportion to predict the prognosis of ONFH:There was significant difference between collapse group and non-collapse group (P=0.001). The proximal sclerosis proportion of collapse group was13.11%±10.65%and the non-collapse groupwas51.91%±21.29%.Drew the ROC curve, are a under the curve A=0.967.We took the Youden’s index maximum point(0.902) as the critical point, which was29.24%.To facilitate clinical application, we selected30%.According to the critical point of collapse diagnosis of ONFH, Sensitivity was97.30%, specificity was87.5%, accuracy was94.01%, false positives rate (misdiagnosis rate) was12.5%,false negative rate (omission diagnostic rate) was2.70%, diagnostic odds ratio was252, positive likelihood ratio was7.78, negative likelihood ratio was0.03, the positive predictive value was0.94, negative predictive value was0.94and Youden’s index was0.85.3. Research of the correlation between ONFH TCM constitutions and the proportion of proximal sclerosis:Different TCM constitutions had statistically significant difference in the proportion of proximal sclerosis (P=0.046). Yang-deficiency constitution was0.20±0.25, dampness-heat was0.24±0.25, blood-stasis was0.39±0.29, Yang-deficiency combined dampness-heat was0.29±0.37，Yang-deficiency combined blood-stasis was0.35±0.29, and dampness-heat combined blood-stasis was0.42±0.28. There are also differences between the three kinds of single lopsided constitutions (p=0.042).For each pairwise comparison, we found that yang-deficiency constitution are different with blood-stasis constitution (p=0.02) and dampness-heat combined blood-stasis constitution (p=0.02). Proportion of proximal sclerosis was lower in yang-deficiency constitution group than in blood-stasis group.Conclusions:1. Proximal sclerosis provides effective mechanical support and enhances the structural tolerance and anti-deformation ability of the femoral head. It also plays a role of "mechanical umbrella" in the necrotic tissue surface and prevents collapse in ONFH.2. Proximal sclerosis proportion has high diagnostic value for the collapse prediction of ONFH. In clinical practice, the critical point can be30%. When it is more than30%, the risk of collapse is little. If it is less than30%, the risk of collapse is higher and needs to give effective mechanical support. 3. TCM constitutions influence the ONFH repair capacity, Blood-stasis constitution has strong ability to repair but the yang-deficiency constitution is poor which tend to collapse and need positive treatment. The main therapeutic principles should reinforce the kidney and strengthen the spleen.