Maisonneuve fractures need syndesmosis screws.
Ⅳ, Distal tibiofibular diastasis without fractures
Does this fracture dislocation need syndesmosis screws?
A special case ---Does this fracture dislocation need syndesmosis screws?
• The deep deltoid ligment is oriented transversely and inserts into the posterior colliculus of the midial malleolus. It may be exposed only after osteotomy or fracture of the medial malleolus. • It cannot be effectively repaired.
1距骨体关节面略呈前宽后窄 2很多学者认为应在踝关节最 大背伸位时进行下胫腓联合的 固定，以防止踝穴过紧影响术 后背伸活动 3 Griend等（1996）认为在 踝关节最大背伸位固定下胫腓 联合将使踝穴一直处于最宽的 状态，易出现不稳定的倾向， 建议在踝关节背伸5度位固定 下胫腓联合。
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关于下胫腓螺钉断裂？
2. 3.
Old distal tibiofibular diastasis. Hook test
螺钉位置？
下胫腓处？下胫腓远端？下胫腓近端？ AO组织建议在踝关节水平间隙上方2-3cm Geissler等认为应紧靠下胫腓联合的上方
Griend等（1996）认为应在胫骨的腓骨切迹的顶端，即踝 关节水平间隙上方3-4cm
So, type C fracture dislocation with a high
level fibular fracture and deep deltoid ligament injury needs syndesmosis screws. ( only one stabilization complex can be restored without fixing the sydesmosis)
ankle fracture needs syndesmosis screws.
Because two (the medial and syndesmosis) complexes have been destroyed.
Ⅴ, Old distal tibiofibular diastasis
Does this fracture dislocation need syndesmosis screws?
Syndesmosis screws were essential.
So, old distal tibiofibular diastasis
needs syndesmosis screws.
The medial malleolus fracture involved only the anterior colliculus. The posterior colliculus was intact, but the deep deltoid ligament was torn from it.


After fixing the medial malleolus (anterior colliculus) , the medial complex was not restored, because of the injured deltoid ligament. A syndesmosis screw was needed.
So, if medial and lateral fractures
can be anatomically reduced and fixed, and the deep deltoid ligament is intact, syndesmosis screws are not necessary (two stabilized complexes can restore the mortise stability).
McBryde等（1997）通过试验对比得出的结论是，胫距关 节间隙上方2cm是最佳位置。
螺钉的方向？
水平？斜行？
目前意见基本一 致：平行于胫距 关节面且向前倾 斜25～30度
3层皮质 VS 4层皮质？
三层皮质： 螺钉顶端位于胫骨髓腔内，允许在踝关节屈伸过程中适 应下胫腓联合的正常宽度变化的活动 强度？ 四层皮质： 螺钉穿透四层皮质能提供更好的稳定性 负重断裂？ 影响踝关节活动？
Ⅱ,
Type B
Does this fracture dislocation need syndesmosis screws?
Syndesmosis screws were not necessary.
So, type A and type B fracture
dislocation usually need no syndesmosis screws.
Interposition of looseing body
Does this fracture dislocation need syndesmosis screws?
Maisonneuve fracture ( a special type C fracture)
A syndesmosis screw was used to fix the syndesmosis and indirectly fix the fibular fracture
Deep deltoid ligament and interosseous membrane were ruptured.
After fixing the fibula, only one complex was restored.
X-ray photo under valgus and external rotation stress.
The syndesmosis complex is stable.
Two complexes can be restored, after fixing the lateral malleolus.
Ⅲ,
Type C
?
Does this fracture dislocation need syndesmosis screws?
3层皮质螺钉不容易 断裂，4层皮质螺钉 容易断裂？
水平方向螺钉容易断 裂（剪力大），斜行 不容易？ 1枚容易断裂，2枚不 容易断裂？
取出 VS 不取出？
多数学者建议术后常规取出下胫腓螺 钉 有人认为，对于三层皮质螺钉，可以 在取出踝关节其它内固定物的同时取 出下胫腓螺钉，由于螺钉只贯穿三层 皮质，允许螺钉适应下胫腓联合的活 动，不会发生弯曲或折断。 螺钉断裂 纷！！ 取出困难 纠
SYNDESMOSIS SCREWS --WHEN NECESSARY?
Wang Manyi Beijing Jishuitan Hospital
The stabilization structures of ankle can be divided into three complexes (medial, lateral and syndesmosis). If two of the three complexes can be restored, the mortise can be stabilized.
Tricortical Versus Quadricortical Syndesmosis Fixation in Ankle Fractures A prospective, Randomized Study Comparing Two Methods of Syndesmosis Fixation Per Hoiness, MD, and Kunt Stromsoe, MD, PhD J Othop Trauma,18(6),July 2004:331-337 前瞻性随机临床研究 一枚4.5mm皮质骨螺钉通过4层皮质（n=30）VS2枚 3.5mm皮质骨螺钉通过3层皮质（n=34） 结果：术后1年后，两组在功能评分、疼痛和背伸等方面均 没有显著性差异
•Distal tibiofibular diastasis without any fractures. •Syndesmosis ligaments and deltoid ligament were ruptured.
•Two complexes were unstable.
So, distal tibiofibular diastasis without
Ⅰ,
Type A
Does this fracture dislocation need syndesmosis screws?
After the lateral malleolus was reduced and fixed, two complexes was restored. Syndesmosis screws were not necessary.
1枚 VS 2枚？
目前生物力学试验 证实，二者在生物 力学表现上的差异 不显著
是否使用拉力螺钉？
使用下胫腓螺钉的主要目 的是维持下胫腓联合的正 常位置，不应对其加压
加压螺钉会使下胫腓联合 变窄，从而导致踝关节背 伸受限
如下胫腓联合固定过紧， 在负重时容易发生螺钉弯 曲或折断。
固定下胫腓联合时踝关节的位置
CONCLUSIONS