JXHC Key Laboratory of Digital Orthopedics, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, 152 Aiguo Road, Nanchang, 330006, Jiangxi, China.
Department of Pain Management, The 2Nd Affiliated Hospital, Jiangxi Medical College, Nanchang University, No.1 Minde Road, Nanchang, 330006, Jiangxi, China.
J Orthop Traumatol. 2024 Nov 21;25(1):56. doi: 10.1186/s10195-024-00803-0.
Both initial mechanical stability and subsequent axial interfragmentary micromotion at fracture ends play crucial roles in fracture healing. However, the conversion timing of variable fixation and its effect on and mechanism of fracture healing remain inadequately explored.
A magnesium degradation-induced variable fixation plate (MVFP) for femurs was designed, and its conversion timing was investigated both in vitro and in vivo. Then, locking plates and MVFPs with and without a magnesium shim were implanted in rabbit femur fracture models. X-ray photography and micro computed tomography (micro-CT) were performed to observe the healing of the fracture. Toluidine blue and Masson's trichrome staining were performed to observe new bone formation. The torsion test was used to determine the strength of the bone after healing. Finally, reverse transcription-polymerase chain reaction (RT-PCR) and western blotting were used to detect the expression of osteogenesis-related genes in the three groups.
The MVFP with sample 3 magnesium shim showed greater axial displacement within 15 days in vitro, and its variable capability was likewise confirmed in vivo. X-ray photography and micro-CT indicated increased callus formation in the variable fixation group. Toluidine blue and Masson's trichrome staining revealed less callus formation on the rigid fixation side of the locking plate, whereas the variable fixation group presented more callus formation, more symmetrical intraosseous calli, and greater maturity. The torsion test indicated greater torsional resistance of the healed bone in the variable fixation group. RT-PCR and western blotting revealed that the expression levels of BMP2 and OPG increased during early fracture stages but decreased in late fracture stages, whereas RANKL expression showed the opposite trend in the variable fixation group.
MVFP promoted faster and stronger bone healing in rabbits, potentially by accelerating the expression of BMP2 and modulating the OPG/RANKL/RANK signaling axis. This study offers valuable insights for the clinical application of variable fixation technology in bone plates and contributes to the advancement of both internal fixation technology and theory.
level V.
骨折端初始的机械稳定性和随后的轴向骨折端间微动都对骨折愈合起着至关重要的作用。然而，可变固定的转换时机及其对骨折愈合的影响和机制仍未得到充分探索。
设计了一种镁降解诱导的可变固定接骨板（MVFP），并对其在体外和体内的转换时机进行了研究。然后，将锁定板和带有和不带有镁垫片的 MVFP 植入兔股骨骨折模型中。进行 X 射线摄影和微计算机断层扫描（micro-CT）以观察骨折的愈合情况。采用甲苯胺蓝和 Masson 三色染色观察新骨形成情况。采用扭转试验测定愈合后骨的强度。最后，采用逆转录-聚合酶链反应（RT-PCR）和蛋白质印迹法检测三组骨生成相关基因的表达。
体外第 3 个镁垫片样本的 MVFP 显示出 15 天内更大的轴向位移，体内同样证实了其可变能力。X 射线摄影和 micro-CT 表明可变固定组有更多的骨痂形成。甲苯胺蓝和 Masson 三色染色显示锁定板刚性固定侧的骨痂形成较少，而可变固定组则有更多的骨痂形成，更对称的骨内骨痂，且成熟度更高。扭转试验表明可变固定组愈合骨的抗扭转阻力更大。RT-PCR 和蛋白质印迹法显示，BMP2 和 OPG 的表达水平在骨折早期升高，但在晚期降低，而在可变固定组中 RANKL 的表达则呈现相反的趋势。
MVFP 促进了兔骨折更快更强的愈合，这可能是通过加速 BMP2 的表达并调节 OPG/RANKL/RANK 信号轴来实现的。该研究为临床应用可变固定技术提供了有价值的见解，对内置物技术和理论的发展均有贡献。
5 级。
