Sockalingam Navindravadhanam, Reymond Nils, Rybnikov Alexey, Dubois-Ferriere Victor, Assal Mathieu
Centre ASSAL for Foot Care and Surgery, Hirslanden Clinique La Colline, Geneva, Switzerland.
Foot Ankle Orthop. 2023 Feb 23;8(1):24730114231153140. doi: 10.1177/24730114231153140. eCollection 2023 Jan.
Functional hallux limitus (FHLim) refers to a limitation of hallux dorsiflexion when the first metatarsal head is under load, whereas physiologic dorsiflexion is measured in the unloaded condition. Limited excursion of the flexor hallucis longus (FHL) in the retrotalar pulley has been identified as a possible cause of FHLim. A low-lying or bulky FHL muscle belly could be the cause of this limitation. However, to date, there are no published data regarding the association between clinical and anatomical findings. The purpose of this anatomical study is to correlate the presence of FHLim and objective morphologic findings through magnetic resonance imaging (MRI).
Twenty-six patients (27 feet) were included in this observational study. They were divided into 2 groups, based on positive and negative Stretch Tests. In both groups, we measured on MRI the distance from the most inferior part of the FHL muscle belly and the retrotalar pulley as well as the cross-sectional area of the muscle belly 20, 30, and 40 mm proximal to the retrotalar pulley.
Eighteen patients had a positive Stretch Test and 9 patients had a negative Stretch Test. The mean distance between the most inferior part of the FHL muscle belly and the retrotalar pulley was 6.0 ± 6.4 mm for the positive group and 11.8 ± 9.4 mm for the negative group ( = .039). The mean cross section of the muscle measured at 20, 30, and 40 mm from the pulley were 190 ± 90, 300 ± 112, and 395 ± 123 mm for the positive group and 98 ± 44, 206 ± 72, and 294 ± 61mm for the negative group ( values .005, .019, and .017).
Based on these findings, we can conclude that patients with FHLim do have a low-lying FHL muscle belly causing limited excursion in the retrotalar pulley. However, the mean volume of the muscle belly was comparable in both groups, and therefore bulkiness was not found to be a contributing factor.
Level III, observational study.
功能性拇趾背伸受限（FHLim）是指在第一跖骨头负重时拇趾背伸受限，而生理性背伸是在非负重状态下测量的。距下后滑车处拇长屈肌（FHL）活动度受限已被确定为FHLim的一个可能原因。FHL肌腹位置低或体积大可能是导致这种受限的原因。然而，迄今为止，尚无关于临床和解剖学发现之间关联的已发表数据。本解剖学研究的目的是通过磁共振成像（MRI）将FHLim的存在与客观形态学发现相关联。
本观察性研究纳入了26例患者（27只脚）。根据拉伸试验阳性和阴性将他们分为两组。在两组中，我们在MRI上测量了FHL肌腹最下部与距下后滑车之间的距离，以及距下后滑车近端20、30和40毫米处肌腹的横截面积。
18例患者拉伸试验阳性，9例患者拉伸试验阴性。阳性组FHL肌腹最下部与距下后滑车之间的平均距离为6.0±6.4毫米，阴性组为11.8±9.4毫米（P = 0.039）。距滑车20、30和40毫米处测量的肌腹平均横截面积，阳性组分别为190±90、300±112和395±123平方毫米，阴性组分别为98±44、206±72和294±61平方毫米（P值分别为0.005、0.019和0.017）。
基于这些发现，我们可以得出结论，FHLim患者确实存在FHL肌腹位置低的情况，导致距下后滑车活动度受限。然而，两组肌腹的平均体积相当，因此未发现体积大是一个促成因素。
III级，观察性研究。
