高弓足概述
高弓足是一个描述性术语而不是一个特定的诊断。最简单的高弓足特征是足内侧纵弓过高，后足内翻，或有踝关节跖屈。多数患者具有潜在的神经性疾病，最初的畸形发生在前足跖屈度增加的后足矢状面中。
高弓足病因
历史上已经有许多关于高弓足病因的学说。然而，在Brewerton等人的研究中，回顾了77例高弓足畸形，51例（66％）临床证据表明神经系统受累。Ibrahim随后把高弓足畸形的病因分为神经性、先天性、及外伤性（表1）。高弓足畸形所有潜在的神经原因中，CMT是最常见的神经系统疾病。CMT已被进一步分为4类（表2），其中最显著的是原发性或CMT1型，其表现主要为进行病变且神经传导速度减慢（NCV）；继发性或CMT2型的NCV正常，趋向于无痛。这一观点取得了Krajewski等人的进一步支持。过去的十年取得了很多进展，通过遗传血液筛查，我们对多种形式的CMT病的分子基础有了更清晰的认识。这增加了诊断为有潜在神经系统因素的患者数量，而不是被冠以特发性高弓足的诊断。我们相信只有彻底了解疾病和影像的光谱，才能制定恰当的手术规划和管理。
Table 1 Etiology of pes cavus
表1 高弓足病因
Table 2 Classification of Charcot-Marie-Tooth disease
表2 腓骨肌萎缩症的分型
病例报告
一名19岁的男性，足部疼痛且行走困难，被他的家庭医生转介到我院。患者陈述他的脚自13岁以来不再增长，然而他的足弓高度有所增加。体检发现双侧高弓足伴小趾回缩和大趾僵硬跖屈。患者双侧后足呈现不稳定、无补偿的弓形姿态。Coleman block试验是基于足外侧和后跟踩在方块上时第一趾幅负载的原理，显示当第一序列跖屈被补偿时，患者的后足保持弓形姿态。患者下肢肌肉显得不发达，且双手内在肌群显示有较小程度的消耗。在进一步的追问下，患者报告他的父亲也有类似的足部畸形。膝盖反射消失，没有任何足底反应（Babinski征），整个下肢震动觉减弱。采用医学研究理事会的牛津大学的等级，徒手肌力测量被划分为背屈4级、跖屈5级、内翻5级、外翻2级。负重平片显示足跟倾斜角（为38.2度）和相对高的前足（跖骨-距骨）倾斜角（62.9度）增加。背跖向X片显示跖骨内收大幅增加（图1）。
Fig.1. (A) Preoperative radiograph showing a weight-bearing lateral exhibiting substantial calcaneal inclination (38.2°) and metatarsal declination (62.9°) with lack of parallelism of the talar and metatarsal declinations. (B) Preoperative radiograph showing the dorsoplantar view identifying substantial metatarsal adductus and superimposition of the bones of the lesser tarsus.
图1 （A）术前侧位负重平片显示大幅度的足跟倾斜角（38.2度）和跖骨倾斜角（62.9度），距骨不平行且跖骨倾斜。（B）术前X片显示背跖向视图，可确认跖骨大幅内收和小跗骨叠加。
基于上述检查结果，初步诊断为具有潜在神经功能障碍的后天高弓足畸形，并加快转介到神经科。神经科医师证实该患者外周肌肉无力，四肢反射消失并感觉异常。没有其他神经系统症状，尤其是没有视觉障碍、言语障碍、吞咽困难或听力障碍。NCV和动作反应测试显示外周反应减弱和感觉潜力缺失（表3）。血液测试证实双17p11.2染色体。这些发现与遗传性运动-感觉神经病1型（CMT-1A型）一致，并伴随超过70％的轨迹和等位基因异质性。患者准备就绪，我们决定采用手术治疗来矫正高弓足畸形。
Table 3 Motor and sensory conduction examination for the patient described in this report.
表3 本报告所述患者的运动和感觉传导测试。
手术过程-操作1
患者确定其右足最不稳定，表现为一个触发拇趾及相关趾间关节疼痛、第一序列僵硬跖屈、后足僵硬内翻和前足跖屈。该患者主要担心的是穿鞋后走路艰难或站立2-3小时以上触发拇趾反复发炎，不穿鞋尤其严重。我们选择两次手术来矫正倾斜角，把重点放在采用三关节融合术矫正横向不稳定，以及采用闭合楔形截骨术来提高第一序列。
采用全身麻醉，取仰卧位，大腿绑止血带。同时，腘神经阻滞给药用于术后疼痛管理。行两个切口以暴露三关节。靠近踝关节外侧1厘米处横向切开，以显露距跟后关节面，并通过关节行闭合楔形截骨术，以复位弓形部位。采用7.0部分螺纹拉力螺钉固定距跟关节，将其从足背插入至足底，穿过距骨的颈部进入跟骨。当距跟关节被严格固定，采用部分螺纹拉力螺钉和U形压力钉固定并复位距舟骨和跟骰关节，足弓和前足完全对齐后足。然后通过趾间关节融合术矫正触发拇趾。采用第一跖骨基底背侧闭合楔形截骨术（DCWO）矫正第一序列跖屈，以便改善所述第一序列的整体姿态和功能（图2）。术后前6周应用膝下不负重石膏固定，随后6周采用行走管型石膏。整合融合后的临床和影像学证据，患者开始进行性的负重，直到达到正常功能的恢复，历时约3.5个月。
术后6个月在门诊复查时，患者足部和踝关节保持稳定，但仍表现出前足跖屈（图2）。虽然在手术台上，我们觉得已经达到满意的矫正；然而，这与患者术后行走困难无关。所有患者的踝关节背屈有限，已被占据以补偿前足跖屈。术后患者足跟保持中立位置，患者不再有能力翻转足外侧边缘，以克服踝关节有限的背屈范围。术前和术后的X片证实了距骨小腿关节伴前骨赘一定程度的退变和距骨小腿界面扁平化。基于患者缺乏踏板对脚踝跖屈的补偿导致其持续无法令人满意地走动，我们准备对患者进行二期手术治疗。
Fig. 2. Postoperative radiograph showing the subtalar fusion, talonavicular, calcaneocuboid, and interphalangeal joint fusions, and the base closing wedge osteotomy exhibiting an improved foot position but still exhibiting forefoot equinus and a posterior position of the ankle.
图2 术后X片显示距下融合，距舟骨、跟骰关节和趾间关节融合，基底闭合楔形截骨改善了足部姿态，但仍然表现出前足跖屈和踝关节位置较后。
手术过程-操作2
一期手术后12个月，进行二期手术操作。为了复位踝关节补偿的程度（伪马蹄足），对患者进行全身麻醉，取仰卧位，通过足弓行背侧闭合楔形截骨术，并取出游离体和胫前骨赘。行背侧切口，背侧骨赘和游离体暴露，从距骨小腿关节取出，并通过舟骨和骰骨行Cole背侧闭合楔形截骨术（图3）。通过跖内侧切口进行足底筋膜释放允许DCWO闭合，并利用U形压力钉来实现固定。膝下不负重石膏固定患足持续8周，随后6周采用BYA膝下局部负重石膏。复查时，患者能够移动他的骨盆在跖足之上，且他的步态有显著改善。术后一个普通疗程后患者伤口愈合、骨整合且身体康复，结合术后12个月的功能更强和无痛的专题报告，患者已恢复所有常规负重活动。
Fig. 3. A perioperative photograph identifying the dorsal closing wedge osteotomy fixated with compression staples.
图3 围手术期照片识别背侧闭合楔形截骨术结合U形压力钉固定。
讨论
患者的静态和动态步态评估显示有明显的双边踝关节不稳。此外，我们采用非负重评估（包括使用医学研究理事会的牛津大学5级肌肉量表）鉴定力量和功能，以确定这些结构的康复是否可以实现。肌肉鉴定结果与神经专科医师的观点一致，运用肌电图和神经传导速度测试，证实了神经元障碍的渐进性质、程度和分布。
我们鉴定了各个足踝关节以明确范围、方向和运动质量。距骨小腿关节检查识别出前侧或伪马蹄足畸形、关节退行性变化、踝关节侧向和距下关节不稳。经评估，距下关节能够使跟骨复位到距骨小腿关节内的中间位置，并确保它返回到相对于所述支撑面的垂直位置。我们对本报告中所描述的患者进行检查，证实第一序列僵硬跖屈和后足僵硬内翻都存在潜在畸形，包括距骨小腿关节横向不稳定的姿态和伪马蹄足的足弓。本报告所述的患者曾尝试使用各种矫形器及专门的鞋子，结果都没有成功。因此，我们决定采取手术疗程，着重于建立一个无痛、跖屈和稳定的足部。各种手术矫正已提倡实现所有这些目标，旨在解决连续阶段各个等级的畸形。
对于本患者，我们采用围手术期透视检查来确保固定装置的适当位置，并行闭合楔形距下关节融合术，以解决患者的后足不稳。足弓姿态的矫正与距舟骨和跟骰关节融合术相结合。然后，我们对触发拇趾和拇趾趾间关节炎进行治疗，患者因穿鞋造成了极大的不适，且关联的足弓第一序列僵硬跖屈加重了侧踝关节不稳。趾间关节融合和软组织松解改善了拇趾姿态。Jones肌腱转移矫正足弓第一序列灵活跖屈的记录良好；然而，它不能解决僵硬的畸形。Sammarco和Taylor所倡导的跖骨背侧闭合楔形截骨术曾运用于我们的患者中，他们的第一趾幅错位得到进一步复位。
二期手术后的六个月，患者进行最后的复查，足部稳定并跖屈，且能相对小腿背屈，从而允许（接受手术一侧的）患足有更正常的步态。术后负重X片审查证实足跟倾斜角减小（14.9度），前足（跖骨，距骨）倾斜角也相应减小（31.9度）（图4）。深思熟虑后采用三关节固定术矫正了严重的冠状面畸形，但该病例中未能提供足够的矢状面矫正。因此，2009年5月患者的对侧肢经历了同样的单一程序组合的手术。
Fig.4. Postoperative lateral radiograph showing plantigrade position of the foot with improved calcaneal inclination angle (14.9°)after removal of some of the fixation from the original correction to allow further correction of the deformity and further improvement of the metatarsal inclination angle (31.9°).
图4 最初矫正的固定物移除后允许进一步矫正畸形，术后侧位片显示足部跖屈位置足跟倾斜角改善（14.9度），且跖骨倾斜角也进一步改善（31.9度）。
总之，具有潜在神经性病因的高弓足是一个复杂的足部畸形。必须仔细考虑每个手术步骤以针对性地处理畸形的关键部分，从而达到令人满意的预后。总的预期结果是建立一个无痛、跖屈和稳定的足部，这意味着本组患者必须接受多次外科手术，因此需要适当的心理和医疗支持，以充分应对长期恢复和康复期的需求。
附英文原文:
Overview of Pes Cavus
Pes cavus is a descriptive term and not a specific diagnosis. In its simplest form, pes cavus is characterized by an excessively high medial longitudinal arch, an inverted rearfoot, and an associated true or pseudo ankle equinus. The majority of patients have an underlying neurological component, and initially the deformity occurs in the sagittal plane with increasing degrees of plantarflexion of the forefoot on the rearfoot.
Etiology of Pes Cavus
Historically, there have been many hypotheses as to the etiology of pes cavus. However, in a study by Brewerton et al, who reviewed 77 patients with a pes cavus deformity, 51 (66%) had clinical evidence of neurological involvement. Ibrahim subsequently classified the etiologies of pes cavus deformity into neurological, congenital, and traumatic origins (Table 1). Of all of the underlying neurological causes for pes cavus deformity, CMT is the most common neurological disorder. CMT has been further subdivided into 4 classes (Table 2), the most significant of which is primary or CMT1, which represents the most progressive form and exhibits slow nerve-conduction velocities (NCV); and secondary or CMT2, which tends to be more indolent, with normal NCV. This opinion is further supported by the work by Krajewski et al. Advances have been made over the past decade with a clearer understanding of the molecular basis of several forms of CMT disease, via genetic blood screening. This has increased the number of patients diagnosed with an underlying neurological component rather than being labeled as having idiopathic pes cavus. It is our belief that only with a thorough understanding of these spectra of disorders and presentations can appropriate surgical planning and management be instigated.
Case Report
A 19-year-old man, who complained of painful feet and difficulty walking, was referred to our department by his general practitioner. He reported that his feet had not grown since the age of 13 years, although his pedal arches had increased in height. Physical examination revealed bilateral pes cavus with retraction of the lesser digits and rigid plantarflexed first rays with triggered great toes. His hind-foot assumed an unstable, uncompensated varus position bilaterally. The Coleman block test, which is based on the principle that when the lateral foot and heel are positioned on the block, the first ray is off loaded, showed that when the plantarflexed first ray was compensated, the patient’s rearfoot remained in a varus position. The lower limb musculature appeared underdeveloped, and to a lesser extent his hands displayed wasting of the intrinsic muscles. On further questioning, the patient reported that his father had similar foot deformities. His patella reflexes were absent, no plantar response (Babinski)was established, and vibration perception was reduced throughout the lower limb. Manual muscle power testing, using the Medical Research Council’s Oxford scale, was graded as dorsi-flexion 4, plantarflexion 5, inversion 5, and eversion 2, bilaterally. Weight-bearing plain radiographs revealed an increased calcaneal inclination angle (38.2°) and a correspondingly high forefoot (metatarsal-talar) declination angle (62.9°). The dorsoplantar radiograph showed substantially increased metatarsus adductus (Figure 1).
Based on the aforementioned findings, a primary diagnosis of acquired pes cavus deformity with an underlying neurological deficit was made, and a referral to the consultant neurologist was expedited. The neurologist confirmed peripheral muscle weakness, wasting of both hands and feet with areflexia, and abnormal sensation. There were no other neurological symptoms of note, notably no visual disturbances, speech impediments, dysphagia, or hearing loss. NCV and amplitude of the motor responses tests revealed reduced peripheral responses and absent sensory potentials (Table 3). Blood tests confirmed chromosome 17p 11.2 duplication. These findings were consistent with hereditary motor sensory neuropathy type 1 (CMT1a) with over 70% locus and allelic heterogeneity. After preparing the patient, the decision was made to pursue surgical intervention to correct the debilitating pes cavus deformity.
Surgical Procedures-Operation 1
The patient identified the right foot as his most unstable, and it presented with a triggered hallux and associated interphalangeal joint pain, a rigid plantarflexed first ray, rigid rearfoot varus, and a forefoot equinus. The patient’s chief concerns were with the triggered hallux being repetitively irritated by footwear and difficulty walking or standing for periods greater than 2 to 3 hours, especially when unshod. We opted for a 2-staged approach to correct the misalignment, placing primary attention on addressing the lateral instability with a triple arthrodesis and a closing wedge osteotomy to elevate the first ray.
The operation was performed with the patient under general anesthesia as a day case. The patient was positioned supine with a thigh tourniquet. In concert, a popliteal nerve block was administered for postoperative pain management. Two incisions were used to expose the 3 joints to be fused. A lateral incision was made 1 cm inferior to the lateral malleoli to expose the posterior facet of the subtalar joint, and a closing wedge osteotomy was made through the joint to reduce the varus component. The talocalcaneal arthrodesis was fixated with a 7.0 partially threaded interfragmental cancellous compression screw, which was directed from dorsal to plantar through the neck of the talus into the calcaneus. Once the subtalar joint was rigidly fixated, the midfoot and forefoot were properly aligned to the rearfoot via reduction through the talonavicular and calcaneocuboid joints, which were fixated with partially threaded interfragmental compression screws and compression staples. The triggered hallux was then addressed via an interphalangeal joint fusion via a dorsolinear incision. The plantar-flexed first ray was corrected by means of a basilar dorsal closing wedge osteotomy (DCWO) performed on the first metatarsal, in order to improve the overall position and function of the first ray(Figure 2). Postoperatively, a below-the-knee non-weight-bearing cast was applied for the first 6 weeks, followed by an additional 6 weeks in a walking cast. After clinical and radiographic evidence of fusion consolidation, progressive weight bearing was initiated until return to normal function was achieved, which took approximately 3.5 months.
At the time of outpatient review, at approximately 6 months after the operation, the foot and ankle were stable but still presented with a forefoot equinus (Figure2). While on the operating table, we felt that a satisfactory correction had been achieved; however, this did not correlate with the difficulties that the patient experienced with postoperative walking. All of the patient’s ankle joint dorsiflexion, which was limited, had been taken up to compensate for the forefoot equinus. With the operated heel now held in a neutral position, the patient no longer had the ability to roll off the lateral border of the foot to overcome the limited ankle joint range of dorsiflexion. Preoperative and postoperative radiographs confirmed a degree of articular degeneration in the talocrural joint with anterior osteophytes and flattening of the talocrural interface. Based on the patient’s ongoing inability to satisfactorily ambulate because of the lack of pedal compensation for the ankle equinus, the second stage of the operation was reviewed and the patient made ready.
Surgical Procedures-Operation 2
Twelve months after the first operation, the second procedure was performed. To reduce the degree of ankle joint compensation (pseudo equinus), a dorsally based closing wedge osteotomy through the midfoot, combined with removal of loose bodies and the anterior tibial osteophytes, was undertaken with the patient supine and with the use of general anesthesia. A dorsal incision was used to expose the dorsal osteophytes and loose bodies, which were removed from the talocrural joint, and a Cole DCWO through the navicular and cuboid was also performed (Figure 3). A plantar fascial release through a plantar-medial incision allowed the DCWO to close, and fixation was achieved with the use of compression staples. The foot was again placed in a below-the-knee non-weight–bearing cast for 8 weeks, followed by a partial weight-bearing in a below-the-knee cast for an additional 6 weeks. At review, the patient was able to move his pelvis over the plantigrade foot with significant improvement in his gait. After an unremarkable course of postoperative wound healing, bone consolidation, and physical rehabilitation, the patient had resumed all regular weight-bearing activities with the subjective report of greater function and no pain, by 12 months postoperative.
Discussion
Our patient’s static and dynamic gait assessments revealed significant bilateral ankle instability. Moreover, a non-weight–bearing assessment, including a muscle inventory using the Medical Research Council’s Oxford 5-point scale, appraised strength and function to establish if recruitment of these structures was achievable. This muscular appraisal occurred in concert with recruitment of a consultant neurologist’s opinion, using electromyographic and nerve-conduction velocity tests, which confirmed the progressive nature, extent, and distribution of the neuronal deficits.
Each joint in the foot and ankle was appraised to clarify range, direction, and quality of motion. Examination of the talocrural joint identified an anterior or pseudoequinus deformity, degenerative articular changes, and lateral ankle and subtalar instability. The sub-talar joint was appraised for the ability of the calcaneus to reduce to a neutral position within the talocrural joint and to ensure that it returned to a vertical position relative to the supporting surface. Our examination of the patient described in this report confirmed that the underlying deformity existed in both the rigid plantarflexed first and rigid rearfoot varus, consisting in the talocrural joint functioning in a laterally unstable position and the midfoot with a pseudoequinus. In the patient whom we describe in this report, various orthoses and specialized footwear had previously been tried without success. Therefore, we decided to pursue a surgical course that focused on establishing a pain-free, plantigrade, and stable foot. A variety of surgical corrections have been advocated to achieve each of these goals, with the objective of addressing each level of the deformity in sequential stages.
In the patient whom we describe in this report, we used peri-operative fluoroscopy to assure appropriate position and location of the fixation devices, and we performed a closing wedge, subtalar joint fusion to address our patient’s rearfoot instability. The midfoot position was then addressed with talonavicular and calcaneocuboid fusions. Thereafter, we attended to the triggered position of the hallux and the hallux interphalangeal joint irritation, which was due to footwear that caused considerable discomfort for the patient, and the associated rigid plantarflexed first ray was accentuating the lateral ankle instability. Fusion of the interphalangeal joint and softtissue release improved the hallucal position. The Jones tendon transfer is well documented for the correction of a flexible plantarflexed first ray; however, it cannot address a rigid deformity, and Sammarco and Taylor advocated a dorsolateral closing wedge osteotomy of the metatarsal, which, once undertaken in our patient, further reduced the misalignment of the first ray position.
At final review, at 6 months after the second operation, the patient presented with astable, plantigrade foot, allowing relative dorsi-flexion of the foot on the leg, which in turn enabled a more normal gait on the operated side. Review of the postoperative weight-bearing plain radiographs identified a decreased calcaneal inclination angle (14.9°)and a correspondingly reduced forefoot (metatarsal-talar) declination angle(31.9°) (Figure 4). On reflection the triple arthrodesis corrected the severe frontal plane deformity, but in this case failed to provide adequate sagittal correction. Therefore the patient underwent the same surgical invention as a combined single procedure on the contralateral limb in May 2009.
In conclusion, pes cavus, where there is an underlying neurological etiology, is a complicated foot deformity. Careful consideration of each surgical procedure directed to address the key components of the deformity is required to achieve a satisfactory outcome. The overall desired outcome is to establish a pain-free, plantigrade, and stable foot, which means this group of patients will need to undergo substantial surgical intervention and therefore require appropriate psychological and medical support to adequately cope with the demands of a long recovery and rehabilitation period.
由MediCool医库软件 赵婷 陆晓玲 编译
原文来自：
Surgical Management of Pes Cavus Deformity with an Underlying Neurological Disorder: A Case Presentation
The Journal of Foot & Ankle Surgery 50 (2011) 235–240
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