Okoro Tosan, Teoh Kar Hao, Tanaka Hiro
Department of Arthroplasty, Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust, Oswestry SY10 7AG, United Kingdom.
Department of Orthopaedic Surgery, Princess Alexandra Hospital NHS Trust, Harlow CM20 1QX, United Kingdom.
World J Orthop. 2021 Aug 18;12(8):548-554. doi: 10.5312/wjo.v12.i8.548.
Locking plate fixation in osteoporotic ankle fractures may fail due to cut-out or metalwork failure. Fibula pro-tibia fixation was a technique prior to the advent of locking plates that was used to enhance stability in ankle fractures by achieving tri or tetra-cortical fixation. With locking plates, the strength of this fixation construct can be further enhanced. There is lack of evidence currently on the merits of tibia-pro-fibula augmented locking plate fixation of unstable ankle fractures.
To assess if there is increased strength to failure, in an ankle fracture saw bone model, with a fibula pro-tibia construct when compared with standard locking plate fixation.
Ten osteoporotic saw bones with simulated supination external rotation injuries were used. Five saw bones were fixed with standard locking plates whilst the other 5 saw bones were fixed with locking plates in a fibula pro-tibia construct. The fibula pro-tibia construct involved fixation with 3 consecutive locking screws applied across 3 cortices proximally from the level of the syndesmosis. All fixations were tested in axial external rotation to failure on an electromagnetic test frame (MTS 858 Mini-Bionix test machine, MTS Corp, Eden Praire, MN, United States). Torque at 30 degrees external rotation, failure torque, and external rotation angle at failure were compared between both groups and statistically analyzed.
The fibula pro-tibia construct demonstrated a statistically higher torque at 30 degrees external rotation (4.421 ± 0.796 N/m 1.451 ± 0.467 N/m; -test = 0.000), as well as maximum torque at failure (5.079 ± 0.694N/m 2.299 ± 0.931 N/m; -test = 0.001) compared to the standard locking plate construct. The fibula pro-tibia construct also had a lower external rotation angle at failure (54.7 ± 14.5 67.7 ± 22.9).
The fibula pro-tibia locking plate construct demonstrates biomechanical superiority to standard locking plates in fixation of unstable ankle fractures in this saw bone model. There is merit in the use of this construct in patients with unstable osteoporotic ankle fractures as it may aid improved clinical outcomes.
骨质疏松性踝关节骨折采用锁定钢板固定可能会因螺钉穿出或内固定失败而失效。在锁定钢板出现之前，腓骨向胫骨固定是一种用于通过实现三皮质或四皮质固定来增强踝关节骨折稳定性的技术。使用锁定钢板时，这种固定结构的强度可进一步提高。目前缺乏关于不稳定踝关节骨折采用腓骨向胫骨增强锁定钢板固定优点的证据。
在踝关节骨折锯骨模型中，评估与标准锁定钢板固定相比，采用腓骨向胫骨结构时，骨折至失效的强度是否增加。
使用10个模拟旋后外旋损伤的骨质疏松锯骨。5个锯骨用标准锁定钢板固定，另外5个锯骨用腓骨向胫骨结构的锁定钢板固定。腓骨向胫骨结构包括从下胫腓联合水平向近端连续应用3枚锁定螺钉穿过3层皮质进行固定。所有固定在电磁试验框架（美国明尼苏达州伊登普雷里市MTS公司的MTS 858 Mini - Bionix试验机）上进行轴向外旋至失效测试。比较两组在30度外旋时的扭矩、失效扭矩和失效时的外旋角度，并进行统计学分析。
与标准锁定钢板结构相比，腓骨向胫骨结构在30度外旋时的扭矩（4.421±0.796 N/m对1.451±0.467 N/m；t检验 = 0.000）以及失效时的最大扭矩（5.079±0.694 N/m对2.299±0.931 N/m；t检验 = 0.001）在统计学上更高。腓骨向胫骨结构在失效时的外旋角度也更低（54.7±14.5对67.7±22.9）。
在该锯骨模型中，腓骨向胫骨锁定钢板结构在固定不稳定踝关节骨折方面显示出比标准锁定钢板更好的生物力学性能。对于不稳定的骨质疏松性踝关节骨折患者，使用这种结构可能有助于改善临床结果，因此具有应用价值。
