Objective: To explore the predictive effect of the femoral neck strength composite indexes on femoral head collapse in non-traumatic osteonecrosis of the femoral head (ONFH) compared with bone turnover marker.
Methods: The non-traumatic ONFH patients who were admitted and received non-surgical treatment between January 2010 and December 2016 as the research object. And 96 cases (139 hips) met the selection criteria and were included in the study. There were 54 males (79 hips) and 42 females (60 hips), with an average age of 40.2 years (range, 22-60 years). According to whether the femoral head collapsed during follow-up, the patients were divided into collapsed group and non-collapsed group. The femoral neck width, hip axis length, height, body weight, and bone mineral density of femoral neck were measured. The femoral neck strength composite indexes, including the compressive strength index (CSI), bending strength index (BSI), and impact strength index (ISI), were calculated. The bone turnover marker, including the total typeⅠcollagen amino terminal elongation peptide (t-P1NP), β-crosslaps (β-CTx), alkaline phosphatase (ALP), 25 hydroxyvitamin D [25(OH)D], and N-terminal osteocalcin (N-MID), were measured. The age, gender, height, body weight, body mass index (BMI), bone mineral density of femoral neck, etiology, Japanese Osteonecrosis Investigation Committee (JIC) classification, femoral neck strength composite indexes, and bone turnover marker were compared between the two groups, and the influencing factors of the occurrence of femoral head collapse were initially screened. Then the significant variables in the femoral neck strength composite indexes and bone turnover marker were used for logistic regression analysis to screen risk factors; and the receiver operating characteristic (ROC) curve was used to determine the significant variables' impact on non-traumatic ONFH.
Results: All patients were followed up 3.2 years on average (range, 2-4 years). During follow-up, 46 cases (64 hips) had femoral head collapse (collapsed group), and the remaining 50 cases (75 hips) did not experience femoral head collapse (non-collapsed group). Univariate analysis showed that the difference in JIC classification between the two groups was significant ( Z=-7.090, P=0.000); however, the differences in age, gender, height, body weight, BMI, bone mineral density of femoral neck, and etiology were not significant ( P>0.05). In the femoral neck strength composite indexes, the CSI, BSI, and ISI of the collapsed group were significantly lower than those of the non-collapsed group ( P<0.05); in the bone turnover marker, the t-P1NP and β-CTx of the collapsed group were significantly lower than those of the non-collapsed group ( P<0.05); there was no significant difference in N-MID, 25(OH)D or ALP between groups ( P>0.05). Multivariate analysis showed that the CSI, ISI, and t-P1NP were risk factors for femoral collapse in patients with non-traumatic ONFH ( P<0.05). ROC curve analysis showed that the cut-off points of CSI, BSI, ISI, t-P1NP, and β-CTx were 6.172, 2.435, 0.465, 57.193, and 0.503, respectively, and the area under the ROC curve (AUC) were 0.753, 0.642, 0.903, 0.626, and 0.599, respectively.
Conclusion: The femoral neck strength composite indexes can predict the femoral head collapse in non-traumatic ONFH better than the bone turnover marker. ISI of 0.465 is a potential cut-off point below which future collapse of early non-traumatic ONFH can be predicted.
目的: 与骨转换标志物比较，探讨股骨颈骨强度综合指数对非创伤性股骨头坏死（osteonecrosis of the femoral head，ONFH）患者股骨头塌陷发生的预测作用。.
方法: 以 2010 年 1 月—2016 年 12 月收治并接受非手术治疗的非创伤性 ONFH 患者作为研究对象，其中 96 例（139 髋）符合选择标准纳入研究。男 54 例（79 髋），女 42 例（60 髋）；年龄 22～60 岁，平均 40.2 岁。根据随访期间是否出现股骨头塌陷，将患者分为塌陷组和未塌陷组。测量患者股骨颈宽度、髋轴长度、身高、体质量及股骨颈骨密度，计算股骨颈骨强度综合指数，包括抗压强度指数（compressive strength index，CSI）、抗折强度指数（bending strength index，BSI）、抗冲击强度指数（impact strength index，ISI）；测量骨转换标志物血清总Ⅰ型胶原氨基端延长肽（total typeⅠcollagen amino terminal elongation peptide，t-P1NP）、β-胶原特殊序列（β-crosslaps，β-CTx）、ALP、25 羟基维生素 D ［25 hydroxyvitamin D，25（OH）D］、N 端骨钙素（N-terminal osteocalcin，N-MID）水平。比较两组患者年龄、性别、身高、体质量、体质量指数（body mass index，BMI）、股骨颈骨密度、ONFH 病因、日本骨坏死调查委员会（JIC）分型以及股骨颈骨强度综合指数、骨转换标志物，初步筛选股骨头塌陷发生的影响因素。取股骨颈骨强度综合指数及骨转换标志物中差异有统计学意义的变量，行 logistic 回归分析，筛选危险因素；并采用受试者操作特征（receiver operating characteristic，ROC）曲线判断其对非创伤性 ONFH 患者股骨头塌陷发生的预测价值。.
结果: 所有患者均获随访，随访时间 2～4 年，平均 3.2 年。随访期间，46 例（64 髋）发生股骨头塌陷（塌陷组），其余 50 例（75 髋）未发生股骨头塌陷（非塌陷组）。单因素分析显示，两组患者 JIC 分型差异有统计学意义（ Z=–7.090， P=0.000）；但年龄、性别、身高、体质量、BMI、股骨颈骨密度及 ONFH 病因比较，差异均无统计学意义（ P>0.05）。股骨颈骨强度综合指数中，塌陷组 CSI、BSI、ISI 均低于非塌陷组（ P<0.05）；骨转换标志物中，塌陷组 t-P1NP 及 β-CTx 低于非塌陷组（ P<0.05），N-MID、25（OH）D 及 ALP 组间比较差异均无统计学意义（ P>0.05）。多因素分析显示，CSI、ISI 和 t-P1NP 是非创伤性 ONFH 患者股骨头塌陷的危险因素（ P<0.05）。ROC 曲线分析显示 CSI、BSI、ISI、t-P1NP、β-CTx 的截断值分别为 6.172、2.435、0.465、57.193、0.503，ROC 曲线下面积（area under the ROC curve，AUC）分别为 0.753、0.642、0.903、0.626、0.599。.
结论: 股骨颈骨强度综合指数比骨转换标志物更能预测非创伤性 ONFH 股骨头塌陷的发生。其中，ISI 0.465 是一个潜在临界值，低于该值可以预测早期非创伤性 ONFH 股骨头塌陷的发生。.
Keywords: Osteonecrosis of the femoral head; bone turnover marker; femoral head collapse; femoral neck strength composite indexes; prediction.