R Adams Cowley Shock Trauma Center, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
J Orthop Trauma. 2009 Oct;23(9):628-33. doi: 10.1097/BOT.0b013e3181b04835.
The 95 degrees angled blade plate is an accepted standard for plating subtrochanteric femoral fractures but can be technically demanding and often requires extensive soft tissue exposure. Proximal femoral locking plates (PFLPs) have been developed for subtrochanteric and pertrochanteric fractures and are potentially easier to apply with less soft tissue dissection. Clinical experience has raised concerns regarding the strength of the PFLP. The purpose of our study was to compare the relative stability of two designs of PFLP with the 95 degrees angled blade plate under loads simulating the first 3 months of progressive weight bearing after fracture fixation.
A comminuted subtrochanteric femoral fracture model was created with a 2-cm gap below the lesser trochanter in 15 synthetic femora. Fracture fixation of three plates (95 degrees angled blade plate [blade plate], the original version of the PFLP [O-PFLP], and the newest version of the PFLP [N-PFLP]), all manufactured by Synthes, Inc., Paoli, PA, was tested under progressive cyclic loading to reproduce progressive weight bearing during 3 months after fracture fixation. The force and number of cycles to reach 5 mm of displacement of the femoral head or failure of the implant were compared for each implant.
N-PFLPs were significantly stiffer than blade plates and O-PFLPs (P = 0.01) and had a trend toward withstanding more cycles before failure (P = 0.06). All five O-PFLPs demonstrated catastrophic fatigue failure before completion of the protocol. One each of the blade plates and the N-PFLPs failed to complete the protocol (P = 0.04).
In the model studied, N-PFLPs were shown to have biomechanical properties that were at least equivalent to those of the blade plate. The fatigue failures of O-PFLPs mirrored our clinical experience. Use of the N-PFLP might be a viable alternative fixation method for comminuted subtrochanteric femoral fractures that currently are treated with blade plates.
95 度角 blade 钢板是治疗股骨转子下骨折的标准方法，但技术要求高，往往需要广泛的软组织暴露。股骨近端锁定钢板（PFLP）已被开发用于治疗转子下和转子间骨折，并且在应用时潜在地更容易，软组织剥离更少。临床经验引起了对 PFLP 强度的关注。本研究的目的是比较两种 PFLP 设计与 95 度角 blade 钢板在模拟骨折固定后最初 3 个月渐进性负重下的相对稳定性。
在 15 个合成股骨中，在小转子下方 2cm 处创建粉碎性转子下股骨骨折模型。对三种钢板（95 度角 blade 钢板[blade plate]、原始版 PFLP[O-PFLP]和最新版 PFLP[N-PFLP]）进行骨折固定，均由宾夕法尼亚州 Paoli 的 Synthes，Inc. 制造，在渐进性循环载荷下进行测试，以模拟骨折固定后 3 个月渐进性负重。比较每种植入物达到股骨头 5mm 位移或植入物失效的力和循环次数。
N-PFLP 比 blade plate 和 O-PFLP 明显更硬（P = 0.01），在失效前具有承受更多循环的趋势（P = 0.06）。所有 5 个 O-PFLP 在完成方案前均发生灾难性疲劳失效。1 个 blade plate 和 1 个 N-PFLP 未能完成方案（P = 0.04）。
在研究的模型中，N-PFLP 的生物力学性能至少与 blade plate 相当。O-PFLP 的疲劳失效反映了我们的临床经验。对于目前用 blade plate 治疗的粉碎性转子下股骨骨折，使用 N-PFLP 可能是一种可行的替代固定方法。
