Objective: To perfect the theory system of minimally invasive treatment for osteonecrosis of the femoral head (ONFH) with β tricalcium phosphate (β-TCP) bioceramic system and evaluate the effectiveness.
Methods: Eighteen New Zealand white rabbits aged 7-8 months were used to establish an animal model to verify the vascularization of porous β-TCP bioceramic rods. Micro-CT based three-dimensional reconstruction and fluorescence imaging were used to display the new blood vessels at 4, 8, and 12 weeks after operation. The inserting depth, number and diameter of vessels in the encapsulated area were analyzed. Nine pig femoral specimens were randomly divided into 3 groups ( n=3): group A was normal femur; group B had cavity (core decompression channel+spherical bone defect in femoral head); in group C, mixed bioceramic granules were implanted to fill the defect in femoral head, and porous β-TCP bioceramic rod was implanted into decompression channel. The stiffness and yield load of specimens were analyzed by biomechanical test. A multicenter retrospective study was conducted to analyze 200 patients (232 hips) with femoral head necrosis treated with bioceramic system in 7 hospitals in China between January 2012 and July 2018. There were 145 males and 55 females, with an average age of 42 years (range, 17-76 years). According to the Association Research Circulation Osseous (ARCO) stage, 150 hips were in stage Ⅱ and 82 hips in stage Ⅲ. Postoperative imaging assessment was carried out regularly, and hip function was evaluated by Harris score. The effectiveness of ARCO stage Ⅱ and Ⅲ was also compared.
Results: Animal experiments showed that blood vessels could grow into the encapsulated area and penetrate it at 12 weeks. The inserting depth, number and diameter of blood vessels in the encapsulated area gradually increased, and there was significant difference between different time points ( P<0.05). Biomechanical tests showed that the stiffness and yield load of specimens in groups B and C were significantly lower than those in group A, while the yield load in group B were significantly lower than that in group C ( P<0.05). The stiffness in group C was restored to 41.52%±3.96% in group A, and the yield load was restored to 46.14%±7.85%. Clinical study showed that 200 patients were followed up 6-73 months, with an average of 22.7 months. At last follow-up, 12 patients (16 hips) underwent total hip arthroplasty, and the hip survival rate was 93.10%. According to the imaging evaluation, 184 hips (79.31%) were stable and 48 (20.69%) were worse. Harris score (79.3±17.3) was significantly higher than that before operation (57.3±12.0) ( t=18.600, P=0.000). The excellent rate of hip function was 64.22% (149/232). The survival rate of hip joint, imaging score and Harris score of patients in ARCO stage Ⅱ were better than those in ARCO stage Ⅲ ( P<0.05).
Conclusion: β-TCP bioceramic system can guide the abundant blood supply of greater trochanter and femoral neck to the femoral head to promote repair; it can partly restore the mechanical properties of the femoral head and neck in the early stage, providing a new minimally invasive hip-preserving method for patients with ONFH, especially for those in early stage.
目的: 完善 β 磷酸三钙（β tricalcium phosphate，β-TCP）生物陶瓷系统微创治疗股骨头坏死（osteonecrosis of the femoral head，ONFH）的理论体系，评估其临床疗效。.
方法: 取 7～8 月龄雄性新西兰大白兔 18 只制备血管化动物模型，术后 4、8、12 周采用 micro-CT 扫描血管三维重建和荧光背景下血管显像观察新生血管形态，并计算血管长入包裹区的深度、血管数目以及血管直径。取 9 个猪股骨标本随机分为 3 组（ n=3）：A 组为正常股骨头颈组；B 组为空腔组（隧芯减压通道+股骨头内球形骨缺损）；C 组为植骨组，打压植入混合陶瓷颗粒填充股骨头内球形缺损，骨隧道内植入 β-TCP 多孔生物陶瓷棒。行生物力学检测计算标本的刚度及屈服载荷。多中心回顾分析 2012 年 1 月—2018 年 7 月，国内 7 所医疗中心行生物陶瓷系统微创保髋治疗的 ONFH 患者 200 例（232 髋）。其中男 145 例，女 55 例；年龄 17～76 岁，平均 42 岁。按照国际骨循环协会（ARCO）分期为Ⅱ期 150 髋，Ⅲ期 82 髋。术后定期对患者进行影像学评估，采用 Harris 评分对髋关节功能进行评价，并比较 ARCO Ⅱ期与Ⅲ期患者的临床疗效。.
结果: 动物实验结果显示血管可由多孔生物陶瓷棒非包裹区长入包裹区，至 12 周时可见血管贯穿包裹区。随术后时间延长，血管长入包裹区的深度、血管数目、血管直径均逐渐增加，各时间点间比较差异均有统计学意义（ P<0.05）。生物力学检测示，B、C 组标本刚度和屈服载荷显著低于 A 组，B 组屈服载荷显著低于 C 组，差异均有统计学意义（ P<0.05）；C 组股骨头颈的刚度恢复至 A 组的 41.52%±3.96%，屈服载荷恢复至 A 组的 46.14%±7.85%。临床研究显示，200 例患者均获随访，随访时间 6～73 个月，平均 22.7 个月。至末次随访时有 12 例（16 髋）行全髋关节置换术，髋关节生存率为 93.10%；根据影像学评估，184 髋（79.31%）影像学稳定，48 髋（20.69%）出现影像学进展；Harris 评分为（79.3±17.3）分，较术前（57.3±12.0）分显著改善（ t=18.600， P=0.000）；优良率达 64.22%（149/232）。ARCO Ⅱ期患者在髋关节生存率、影像学评估、Harris 评分方面均优于 ARCO Ⅲ期患者（ P<0.05）。.
结论: β-TCP 生物陶瓷系统微创治疗 ONFH，可引导大转子及股骨颈血运至股骨头内促进坏死修复；术后早期可以部分恢复股骨头颈力学性能；该方法为 ONFH 患者，尤其是早期患者提供了一种新的保髋治疗选择。.
Keywords: Osteonecrosis of the femoral head; bioceramics; biomechanics; multicenter clinical study; vascularization.