Department of Trauma & Orthopaedics, Altnagelvin Hospital, Glenshane Road, Londonderry BT47 6SB, Northern Ireland, United Kingdom; University of Ulster, Northern Ireland, United Kingdom.
Department of Trauma & Orthopaedics, Altnagelvin Hospital, Glenshane Road, Londonderry BT47 6SB, Northern Ireland, United Kingdom.
Foot Ankle Surg. 2021 Jul;27(5):501-509. doi: 10.1016/j.fas.2020.06.009. Epub 2020 Jun 18.
The only classification of Müller-Weiss disease (MWD) is based primarily on Méary's talo-first metatarsal angle. It describes increasing sag of the medial longitudinal arch with greater degrees of compression and fragmentation of the navicular. Purportedly, the talar head pushes the subtalar joint into varus and drives the medial pole of the navicular medially, as it protrudes inferiorly and laterally. Its authors stipulated heel varus as a pre-requisite, coining the term 'paradoxical pes planus varus' to define heel varus and flatfoot as hallmark deformities of the condition.
We measured Méary's and Kite's talocalcaneal angles, heel offset, anteroposterior thickness of the navicular at each naviculocuneiform (NC) joint, medial extrusion of the navicular and calculated percentage compression at each NC joint in 68 consecutive feet presenting with MWD. Morphology and activity at the various peri-navicular joints were studied using SPECT-CT in 45 feet.
Inverse relationships between Méary's angle and degree of navicular compression reach statistical significance at NC2 but not at NC3. Strong correlation exists between medial extrusion and percentage compression at NC2 and NC3. Medial extrusion is significantly greater on the affected side in unilateral cases and on the more compressed side in bilateral cases. Significant inverse relationships exist between Kite's angle and percentage compression at both NC2 and NC3 and degree of medial extrusion of the navicular. No correlation was detected between Kite's angle and either heel offset or Méary's angle. Varus heel offset was present in only 33% of cases. The combination of heel varus and negative Méary's angle was present in just 26% of cases, the commonest combination being heel valgus with sagging at 56%.
Our findings confirm part of Maceira's hypothesized pathomechanism of MWD. Reductions in Kite's talocalcaneal angle confirm that lateral and inferior protrusion of the talar head causes increasing compression and medial extrusion of the navicular. However, such shift of the talar head does not always lead to heel varus. As such, we caution against universal advocacy of lateral displacement calcaneal osteotomy, as the heel is not always in varus in MWD.
Müller-Weiss 病（MWD）的唯一分类主要基于 Méary 的距下第一跖骨角。它描述了内侧纵弓的凹陷随着距骨的压缩和碎裂程度的增加而增加。据称，距骨头将距下关节推向内翻，并在距骨向下和向外侧突出时将其内侧极点向内推动。其作者规定跟骨内翻是前提，并用“反常扁平足内翻”来定义跟骨内翻和扁平足是该病症的标志性畸形。
我们测量了 68 例 MWD 患者的 Méary 和 Kite 的距跟骨角、跟骨偏移量、各跗骨间关节处的跟骨前-后厚度、距骨内侧突出和各跗骨间关节处的距骨压缩百分比。在 45 例中使用 SPECT-CT 研究了各个跗骨间关节的形态和活动度。
Méary 角与距骨压缩程度之间的反比关系在 NC2 处达到统计学意义，但在 NC3 处没有。在 NC2 和 NC3 处，距骨内侧突出与距骨压缩百分比之间存在很强的相关性。在单侧病例中，患侧距骨内侧突出明显较大，在双侧病例中，在受压更严重的一侧更为明显。Kite 角与 NC2 和 NC3 处的距骨压缩百分比和距骨内侧突出程度之间存在显著的反比关系。在 Kite 角与跟骨偏移量或 Méary 角之间未检测到相关性。只有 33%的病例存在跟骨内翻。仅 26%的病例存在跟骨内翻和 Méary 角为负值的组合，最常见的组合是跟骨外翻，其下垂度为 56%。
我们的发现证实了 Maceira 假设的 MWD 病理机制的一部分。Kite 的距跟骨角的减小证实了距骨头的外侧和下侧突出导致距骨的压缩和内侧突出增加。然而，距骨头的这种移位并不总是导致跟骨内翻。因此，我们告诫不要普遍提倡外侧移位跟骨截骨术，因为 MWD 中的跟骨并不总是内翻。
