Huang Jerry I, Peterson Bret, Bellevue Kate, Lee Nicolas, Smith Sean, Herfat Safa
1 Department of Orthopaedics and Sports Medicine, University of Washington Medical Center, Seattle, USA.
2 Department of Orthopaedic Surgery, University of California, San Francisco, USA.
Hand (N Y). 2018 May;13(3):336-340. doi: 10.1177/1558944717701235. Epub 2017 Apr 7.
The goal of this study was to compare the biomechanical stability of a 2.4-mm dorsal spanning bridge plate with a volar locking plate (VLP) in a distal radius fracture model, during simulated crutch weight-bearing.
Five paired cadaveric forearms were tested. A 1-cm dorsal wedge osteotomy was created to simulate an unstable distal radius fracture with dorsal comminution. Fractures were fixed with a VLP or a dorsal bridge plate (DBP). Specimens were mounted to a crutch handle, and optical motion-tracking sensors were attached to the proximal and distal segments. Specimens were loaded in compression at 1 mm/s on a servohydraulic test frame until failure, defined as 2 mm of gap site displacement.
The VLP construct was significantly more stable to axial load in a crutch weight-bearing model compared with the DBP plate (VLP: 493 N vs DBP: 332 N). Stiffness was higher in the VLP constructs, but this was not statistically significant (VLP: 51.4 N/mm vs DBP: 32.4 N/mm). With the crutch weight-bearing model, DBP failed consistently with wrist flexion and plate bending, whereas VLP failed with axial compression at the fracture site and dorsal collapse.
Dorsal spanning bridge plating is effective as an internal spanning fixator in treating highly comminuted intra-articular distal radius fracture and prevents axial collapse at the radiocarpal joint. However, bridge plating may not offer advantages in early weight-bearing or transfer in polytrauma patients, with less axial stability in our crutch weight-bearing model compared with volar plating. A stiffer 3.5-mm DBP or use of a DBP construct without the central holes may be considered for distal radius fractures if the goal is early crutch weight-bearing through the injured extremity.
本研究的目的是在模拟腋杖负重过程中，比较2.4毫米背侧跨关节桥接钢板与掌侧锁定钢板（VLP）在桡骨远端骨折模型中的生物力学稳定性。
对五对尸体前臂进行测试。制作一个1厘米的背侧楔形截骨术，以模拟伴有背侧粉碎的不稳定桡骨远端骨折。骨折分别用VLP或背侧桥接钢板（DBP）固定。将标本安装在腋杖把手上，并将光学运动跟踪传感器附着于近端和远端节段。在伺服液压试验框架上以1毫米/秒的速度对标本施加压缩载荷，直至失效，失效定义为间隙部位移位2毫米。
在腋杖负重模型中，与DBP钢板相比，VLP结构对轴向载荷的稳定性显著更高（VLP：493牛 vs DBP：332牛）。VLP结构的刚度更高，但无统计学意义（VLP：51.4牛/毫米 vs DBP：32.4牛/毫米）。在腋杖负重模型中，DBP通常因腕关节屈曲和钢板弯曲而失效，而VLP因骨折部位的轴向压缩和背侧塌陷而失效。
背侧跨关节桥接钢板作为一种内部跨关节固定器，在治疗高度粉碎的关节内桡骨远端骨折方面是有效的，并且可防止桡腕关节处的轴向塌陷。然而，桥接钢板在多发伤患者早期负重或转移方面可能并无优势，在我们的腋杖负重模型中，其轴向稳定性低于掌侧钢板。如果目标是通过受伤肢体早期使用腋杖负重，对于桡骨远端骨折，可考虑使用更坚固的3.5毫米DBP或使用无中心孔的DBP结构。
