PURPOSE Ankle lateral collateral ligament complex has been the focus of multiple studies. However, there are no specific descriptions of how these ligaments are connected to each other as part of the same complex. The aim of this study was to describe in detail the components of the lateral collateral ligament complex-ATFL and CFL-and determine its anatomical relationships. METHODS An anatomical study was performed in 32 fresh-frozen below-the-knee ankle specimens. A plane-per-plane anatomical dissection was performed. Overdissecting the area just distal to the inferior ATFL fascicle was avoided to not alter the original morphology of the ligaments and the connecting fibers between them. The characteristics of the ATFL and CFL, as well as any connecting fibers between them were recorded. Measures were obtained in plantar and dorsal flexion, and by two different observers. RESULTS The ATFL was observed as a two-fascicle ligament in all the specimens. The superior ATFL fascicle was observed intra-articular in the ankle, in contrast to the inferior fascicle. The mean distance measured between superior ATFL fascicle insertions increases in plantar flexion (median 19.2 mm in plantar flexion, and 12.6 mm in dorsal flexion, p < 0.001), while the same measures observed in the inferior ATFL fascicle does not vary (median 10.6 mm in plantar flexion, and 10.6 mm in dorsal flexion, n.s.). The inferior ATFL fascicle was observed with a common fibular origin with the CFL. The CFL distance between insertions does not vary with ankle movement (median 20.1 mm in plantar flexion, and 19.9 mm in dorsal flexion, n.s.). The inferior ATFL fascicle and the CFL were connected by arciform fibers, that were observed as an intrinsic reinforcement of the subtalar joint capsule. CONCLUSION The superior fascicle of the ATFL is a distinct anatomical structure, whereas the inferior ATFL fascicle and the CFL share some features being both isometric ligaments, having a common fibular insertion, and being connected by arciform fibers, and forming a functional and anatomical entity, that has been named the lateral fibulotalocalcaneal ligament (LFTCL) complex. The clinical relevance of this study is that the superior fascicle of the ATFL is anatomical and functionally a distinct structure from the inferior ATFL fascicle. The superior ATFL fascicle is an intra-articular ligament, that will most probably not be able to heal after a rupture, and a microinstability of the ankle is developed. However, when the LFTCL complex is injured, classical ankle instability resulted. In addition, because of the presence of LFTCL complex, excellent results are observed when an isolated repair of the ATFL is performed even when an injury of both the ATFL and CFL exists.

中文翻译：

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外侧腓骨局部韧带复合体：踝关节稳定等距结构。

目的踝关节外侧副韧带复合体一直是多项研究的重点。但是，对于这些韧带如何作为同一复合物的一部分相互连接，没有具体描述。这项研究的目的是详细描述外侧副韧带复合体ATFL和CFL的成分，并确定其解剖关系。方法对32例新鲜冷冻的膝下踝关节标本进行了解剖学研究。进行了逐平面解剖解剖。避免过度解剖下ATFL束远端的区域，以免改变韧带及其之间的连接纤维的原始形态。记录了ATFL和CFL的特性，以及它们之间的任何连接光纤。测量了足底和背屈，和两个不同的观察者。结果在所有标本中观察到ATFL为两束韧带。与下束相反，在踝关节内观察到了上ATFL束。在上侧ATFL束插入之间测得的平均距离在plant屈中增加（plant屈中位数为19.2 mm，在背屈中位数为12.6 mm，p <0.001），而在下ATFL束中观察到的相同测量值没有变化（中位数为10.6 mm）。 （足底屈曲）和背侧屈曲10.6 mm，ns）。观察到下部ATFL纤维束与CFL共同存在腓骨起源。插入之间的CFL距离不随踝关节运动而变化（足底屈曲中位数为20.1毫米，背屈中位数为19.9毫米，ns）。下ATFL纤维束和CFL通过弓形纤维连接，被认为是距下关节囊的固有增强。结论ATFL的上束是独特的解剖结构，而ATFL的下束和CFL的某些特征是等长韧带，具有共同的腓骨插入，并由弓形纤维连接，并形成功能和解剖实体，被称为外侧腓总韧带（LFTCL）复合体。这项研究的临床意义是，ATFL的上束在解剖学上和功能上与下层ATFL束不同。上层ATFL束是关节内韧带，在破裂后极有可能无法愈合，从而导致踝关节微不稳定。但是，当LFTCL复合体受伤时，导致经典的踝关节不稳。另外，由于LFTCL复合物的存在，即使对ATFL和CFL都存在损伤，当进行ATFL的单独修复时，也观察到极好的结果。