关键词: 股骨头坏死, 骨代谢, 病因, ARCO分期, Ⅰ型前胶原N末端前肽

Abstract: BACKGROUND: Currently, there is a lack of large sample studies to analyze the bone metabolism level of patients with femoral head necrosis of different etiologies and stages, which is not conducive to the development of better necrosis-promoting repair strategies.
OBJECTIVE: To study the bone metabolism of patients with osteonecrosis of the femoral head with different etiologies and Association Research Circulation Osseous (ARCO) stages. 
METHODS: A retrospective study was performed on 401 patients diagnosed with osteonecrosis of the femoral head as the trial group, and 81 healthy subjects as the control group. The trial group could be divided into three groups according to different etiologies: steroid-induced osteonecrosis of the femoral head, alcoholic osteonecrosis of the femoral head and traumatic osteonecrosis of the femoral head, and were divided into stages II /III /IV according to different ARCO stages. Seven bone metabolism-related indicators of all subjects were collected, including bone metabolism-regulating hormone 25-hydroxyvitamin D and bone conversion markers:  N-terminal propeptide of type I procollagen, degradation product of type I collagen, n-terminal middle molecular fragment of osteocalcin, general biochemical markers of bone metabolism: serum calcium, serum phosphorus, serum alkaline phosphatase. The bone metabolism levels of each group were compared and the independent factors associated with osteonecrosis of the femoral head were determined by binary Logistic regression analysis.  
RESULTS AND CONCLUSION: Compared with the control group, levels of degradation product of type I collagen, N-terminal propeptide of type I procollagen, n-terminal middle molecular fragment of osteocalcin, serum phosphorus and alkaline phosphatase in the trial group were significantly increased (all P < 0.05). Based on the presence or absence of the disease, according to binary Logistic regression analysis, degradation product of type I collagen, N-terminal propeptide of type I procollagen, and n-terminal middle molecular fragment of osteocalcin were independent factors associated with osteonecrosis of the femoral head. The levels of degradation product of type I collagen and N-terminal propeptide of type I procollagen in three groups of patients with different etiologies were higher than normal reference values. The bone metabolism-regulating hormone 25-hydroxyvitamin D and serum calcium in the alcoholic osteonecrosis of the femoral head group were higher than those in the other two groups (P < 0.05). The level of bone metabolism-regulating hormone 25-hydroxyvitamin D in steroid-induced and traumatic osteonecrosis of the femoral head groups was lower than the normal value. There were no significant differences in seven bone metabolism-related indicators in patients with ARCO stages II, III and IV osteonecrosis of the femoral head (all P > 0.05), but degradation product of type I collagen and N-terminal propeptide of type I procollagen in these three groups were higher than normal reference values. Bone metabolism-regulating hormone 25-hydroxyvitamin D in patients with ARCO stage II and ARCO stage IV was lower than the normal reference value. It is concluded that the bone metabolism level of osteonecrosis of the femoral head patients was abnormal. The degradation product of type I collagen and N-terminal propeptide of type I procollagen of osteonecrosis of the femoral head patients with different etiologies and ARCO stages were all higher than the normal reference value, and they were in a state of high bone turnover. Degradation product of type I collagen, N-terminal propeptide of type I procollagen and n-terminal middle molecular fragment of osteocalcin may be risk factors for the pathogenesis of osteonecrosis of the femoral head.

Key words: osteonecrosis of the femoral head, bone metabolism, etiology, ARCO stage, N-terminal propeptide of type I procollagen