O'Neill Patrick J, Logel Kevin J, Parks Brent G, Schon Lew C
C/O Lyn Camire, Department of Orthopaedics, Union Memorial Hospital, Baltimore, MD 21218, USA.
Foot Ankle Int. 2008 Jun;29(6):581-6. doi: 10.3113/FAI.2008.0581.
Obtaining adequate fixation during tibiotalocalcaneal (TTC) arthrodesis may be challenging. Various fixation constructs have been tested biomechanically, but the use of a locking plate has not been reported. We hypothesized that the locking plate with a TTC augmentation screw would provide structural rigidity comparable to that of the intramedullary (IM) nail with a TTC augmentation screw during dorsiflexion testing.
Six matched pairs of fresh frozen cadavers underwent TTC arthrodesis. Specimens in each pair were randomized to receive a locking plate or an intramedullary nail. Each specimen had an additional TTC augmentation screw through the calcaneus, talus, and medial tibia. All samples underwent dorsiflexion testing with determination of structural rigidity at the first cycle (initial rigidity) and last cycle (final rigidity) and the torque required to achieve a failure of 10 degrees of dorsiflexion. Statistical analysis was performed using a paired t-test to determine whether any differences were significant (p < 0.05).
The locking plate construct showed higher final rigidity (mean +/- standard error of the mean) (27.7 +/- 2.6 N-m/degree versus 17.6 +/- 2.1 N-m/degree, p = 0.01) than the IM nail construct. There were no other differences measured.
Rigidity with the the IM nail was inferior to that with locking plate fixation for TTC arthrodesis in one of the four parameters tested.
Screw augmented IM nail fixation and augmented locking plate fixation may offer similar rigidity clinically for TTC arthrodesis.
在胫距跟关节（TTC）融合术中获得足够的固定可能具有挑战性。已经对各种固定结构进行了生物力学测试，但尚未有关于使用锁定钢板的报道。我们假设在背屈测试中，带有TTC增强螺钉的锁定钢板所提供的结构刚度与带有TTC增强螺钉的髓内钉相当。
六对匹配的新鲜冷冻尸体接受了TTC融合术。每对标本随机接受锁定钢板或髓内钉。每个标本都通过跟骨、距骨和胫骨内侧额外置入一枚TTC增强螺钉。所有样本均进行背屈测试，测定第一个循环（初始刚度）和最后一个循环（最终刚度）的结构刚度以及导致背屈10度失败所需的扭矩。使用配对t检验进行统计分析，以确定是否存在显著差异（p < 0.05）。
锁定钢板结构显示出比髓内钉结构更高的最终刚度（平均值±平均标准误差）（27.7±2.6 N·m/度对17.6±2.1 N·m/度，p = 0.01）。未测量到其他差异。
在测试的四个参数之一中，TTC融合术采用髓内钉的刚度低于锁定钢板固定。
螺钉增强的髓内钉固定和增强的锁定钢板固定在临床上可能为TTC融合术提供相似的刚度。
