Michelsen J D, Ahn U M, Helgemo S L
Department of Orthopaedic Surgery, The Johns Hopkins School of Medicine, Baltimore, Maryland, USA.
J Bone Joint Surg Am. 1996 Jul;78(7):1024-31. doi: 10.2106/00004623-199607000-00006.
An experimental study was undertaken with use of axially loaded, unconstrained cadaver ankles to determine the motion patterns seen with progressive stages of the supination-external rotation type of fracture. As described by Lauge-Hansen, these fractures were modeled by transection of the anterior aspect of the capsule and the anterior tibiofibular ligament (stage I), followed by oblique fibular osteotomy ending at the level of the ankle joint (stage II), transection of the posterior aspect of the capsule (stage III), and sequential sectioning of the superficial and deep fibers of the deltoid ligament (stage IV). Thirteen specimens were tested on an apparatus that allowed for controlled loading while the ankle was passed through a physiological range of dorsiflexion and plantar flexion. The ankles were unconstrained about the axial (internal and external rotation) and coronal (varus and valgus angulation) axes. Measurements were made throughout the range of motion in these axes in order to define the kinematic behavior. In the intact specimens, maximum plantar flexion was associated with a mean (and standard deviation) of 1.9 +/- 4.12 degrees of internal rotation of the talus and maximum dorsiflexion, with a mean of 7.2 +/- 3.88 degrees of external rotation. Varus angulation increased slightly with plantar flexion compared with the value in dorsiflexion (2.4 +/- 2.40 compared with 0.3 +/- 1.96 degrees). Internal and external rotation was not affected by fibular osteotomy or by transection of the superficial fibers of the deltoid ligament. Transection of the deep fibers of the deltoid ligament caused a significant (p < 0.02) increase in external rotation of the talus at maximum plantar flexion; this was corrected incompletely by insertion of an anatomical fibular plate. With the numbers available for study, we could not show that varus or valgus angulation was significantly affected by any combination of sectioning of the deltoid ligament and fibular osteotomy. These experiments were repeated with the addition of fixation of the subtalar joint with a talocalcaneal screw. With the number of specimens available, we could detect no significant difference, with respect to axial rotation, due to fixation of the subtalar joint. However, along the coronal axis, increased valgus angulation (p < 0.02) was seen during plantar flexion when either the deep or the superficial fibers of the deltoid ligament had been cut.
These results indicate that stability of the loaded ankle is primarily due to the deltoid ligament, which exerts a restraining influence on external rotation of the talus. Complete fibular osteotomy did not cause abnormal motion of the ankle in the absence of a medial injury. In the presence of a complete injury, lateral reconstruction only partially restored the mechanical integrity of the ankle. The results provide justification for the non-operative treatment of isolated fractures of the lateral malleolus. The data also suggest that a lateral fracture associated with a major injury of the deltoid ligament should be treated with anatomical lateral fixation followed by immobilization without early motion, to allow adequate healing of the deltoid ligament at its resting length.
采用轴向加载、无约束的尸体踝关节进行实验研究，以确定旋后-外旋型骨折进展阶段的运动模式。如Lauge-Hansen所描述，这些骨折通过切开关节囊前侧和胫腓前韧带（I期）进行模拟，随后进行斜形腓骨截骨，截骨端止于踝关节水平（II期），切开关节囊后侧（III期），并依次切断三角韧带的深浅纤维（IV期）。在一台可控制加载的仪器上对13个标本进行测试，同时使踝关节在背屈和跖屈的生理范围内活动。踝关节在轴向（内旋和外旋）和冠状轴（内翻和外翻成角）上无约束。在这些轴的整个运动范围内进行测量，以确定运动学行为。在完整标本中，最大跖屈时距骨平均（及标准差）内旋1.9±4.12度，最大背屈时距骨平均外旋7.2±3.88度。与背屈时相比，跖屈时内翻成角略有增加（分别为2.4±2.40度和0.3±1.96度）。腓骨截骨或切断三角韧带浅层纤维对内外旋无影响。切断三角韧带深层纤维导致最大跖屈时距骨外旋显著增加（p<0.02）；通过植入解剖型腓骨钢板未完全纠正。根据现有研究样本数量，我们无法表明三角韧带切断和腓骨截骨的任何组合对内外翻成角有显著影响。在增加用距下关节螺钉固定距下关节的情况下重复这些实验。根据现有标本数量，我们未检测到距下关节固定对轴向旋转有显著差异。然而，在冠状轴上，当切断三角韧带深层或浅层纤维时，跖屈过程中外翻成角增加（p<0.02）。
这些结果表明，负重踝关节的稳定性主要归因于三角韧带，其对距骨外旋有抑制作用。在没有内侧损伤的情况下，完全腓骨截骨不会导致踝关节异常运动。在存在完全损伤时，外侧重建仅部分恢复了踝关节的力学完整性。这些结果为单纯外踝骨折的非手术治疗提供了依据。数据还表明，与三角韧带严重损伤相关的外侧骨折应采用解剖型外侧固定，随后固定且早期不活动，以使三角韧带在其静息长度下充分愈合。
