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Abstract
People with Charcot-Marie-Tooth (CMT) disease often undergo foot and ankle surgery, as foot deformities are common and cause a degree of functional limitations impairing quality of life. Surgical approaches are variable and there are no evidence-based guidelines. A multidisciplinary approach involving neurology, physical therapy and orthopaedic surgery is ideal to provide guidance on when to refer for surgical opinion and when to intervene. This review outlines the range of foot deformities associated with CMT, their clinical assessment, and their conservative and surgical and postoperative management.
- HMSN (CHARCOT-MARIE-TOOTH)
- SURGERY
Data availability statement
Data sharing not applicable as no datasets generated and/or analysed for this study.
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Introduction
Charcot-Marie-Tooth (CMT) disease is the most common inherited neuropathy with an estimated prevalence ranging from 1 in 2500 to 1 in 10 000.1–3 It encompasses a group of disorders named CMT and related disorders, which include demyelinating and axonal CMT (CMT1), distal hereditary motor neuropathy and hereditary sensory neuropathy. Over 130 genes have been so far identified causing the disease. The classic CMT phenotype is characterised by slowly progressive distal weakness, sensory loss, reduced or absent deep tendon reflexes with onset often in the first two decades of life.4
Foot deformities are a typical feature and occur in 71% of people with CMT.5 They are caused by muscular imbalances between the weaker tibialis anterior overpowered by the stronger peroneus longus muscles (causing first-ray depression), and the weaker peroneus brevis muscle overpowered by the stronger tibialis posterior muscle (causing hindfoot inversion). There is also weakness of intrinsic foot muscles. Deformities include pes cavus (heightened longitudinal arch), hindfoot varus, claw toes and ankle instability (figure 1) .5 Over time this process leads to soft tissue contractures, causing rigid deformities and joint degeneration.6–8 First-line treatments for foot deformities are conservative measures such as stretching, joint mobilisation and orthotics.9 10 Surgery is usually indicated when those measures have failed.11
Typical pes cavus in a CMT patient. Hindfoot varus, claw hallux and lesser toes, plantar flexion of first ray. CMT, Charcot-Marie-Tooth.
In a study of 148 patients presenting to orthopaedic clinics with bilateral cavovarus feet, 78% had an underlying diagnosis of CMT, increasing to 91% where there was a positive family history.12 In a large international cohort of 1953 people with CMT and related disorders 30% of patients underwent corrective surgery.5
The goal of surgical management is to achieve a plantigrade, stable foot by addressing the muscle imbalances and bony deformities.5 There is a lack of evidence-based guidelines regarding optimal surgical management for these patients and surgical decisions are usually individualised. Surgical approaches vary between countries and even between specialised centres with specific expertise in CMT, as highlighted in a recent study.5 In 2016, a European Neuromuscular Centre (ENMC) workshop reached a consensus on procedures deemed to be acceptable in the correction of foot deformities,11 and this was followed by prospective studies in children and adults.13 14
More recently, a consensus statement from a group from the USA published their agreed guidance on the clinical assessment and surgical management of CMT cavovarus deformity, highlighting the importance of a multidisciplinary approach involving neurology, physical therapy and orthopaedic surgery.15
This review aims to outline the typical foot deformities associated with CMT, how they can be assessed and to provide an overview of the surgical management in adult patients, including when to intervene, surgical options and anticipated outcomes.
Foot deformities
An understanding of the typical pattern of muscular imbalance is essential to the management of the foot deformities associated with CMT.16 17
The typical foot deformities involve:
Foot drop due to weakness of the tibialis anterior muscle.
Hindfoot varus: The tibialis posterior on the medial aspect of the hindfoot overpowers the weakened peroneus brevis on the lateral aspect of the hindfoot, causing the hindfoot to move inwards into varus.
Forefoot cavus: The spared peroneus longus runs posteriorly to the distal fibula before passing under the foot on the plantar aspect, inserting onto the medial cuneiform and under surface of the base of the first metatarsal. It overpowers the weakened tibialis anterior leading to plantar flexion of the first ray and inversion at the midfoot,18 19 increasing the height of the foot arch. Furthermore, plantarflexion of the first ray exacerbates the hindfoot varus to maintain the weight-bearing tripod of the foot. The hindfoot inverts at the subtalar joint to bring the fifth metatarsal head down to the same position as the plantarflexed first metatarsal. That process is called a forefoot-driven, hindfoot varus.8
Claw toes: The intrinsic muscles of the foot are initially weaker and overpowered by the extrinsic muscles leading to clawing of the toes. The extensor digitorum muscle inserts onto the dorsum of the middle and distal phalanges leading to dorsiflexion at the metatarsophalangeal joints and flexion at the interphalangeal joints.8 16 20
Functional limitations
The cavovarus foot position overloads the lateral border of the foot and the metatarsal heads. Patients may report lateral forefoot pain, ankle instability, poor shoe fit, reduced balance and falls.8 21 Thickening of the fifth metatarsal and soft tissue callus formation can occur, and sometimes ulceration where there is increased loading of the fifth metatarsal base and head.22 Overloading of the lateral foot border can cause stress fractures of the fifth metatarsal.23
Clawing of the toes, when severe, can result in soft tissue irritation and ulceration over the dorsal surfaces of the interphalangeal joints where they rub in the shoes. The dorsiflexion of the metarsophalangeal joint also causes a downwards plunger effect of the metatarsal head, which can be painful in the metatarsal area of the foot.22
Clinical examination
A comprehensive examination is essential to assess foot deformities (box 1). Alongside the neurological examination, the clinical examination in CMT patients should include detailed inspection, palpation and range of movement testing.15 Particular care should be made to assess these four areas8:
Functional observation: for example, gait, standing, balance.24
Flexibility of deformities. Are they flexible/correctable or fixed/rigid?
Ligamentous laxity and instability.
Muscle groups affected.
Assessment of function and foot deformities in specialist and multidisciplinary clinics
Observation in standing: Muscle wasting, foot and ankle alignment in standing, compensatory strategies (eg, knee hyperextension for proximal weakness or ‘knee bobbing’ for plantar flexion weakness).
Observation of the gait cycle in the sagittal and coronal planes. Key features to observe24:
Which part of the foot strikes the ground first on initial contact (eg, forefoot, lateral plantar border, heel).
Changes in arch height (supination/pronation) and position of calcaneum (valgus/varus) during stance phase.
Early heel rise from mid-stance to toe-off (indication of posterior tibial/tendo Achilles tightness).
Degree of dorsiflexion/plantarflexion during swing phase.
Toe extensor recruitment during swing phase (over or under activity).
Manual muscle testing: Medical Research Council (MRC) scale to assess strength of ankle dorsiflexion, plantarflexion, inversion and eversion, extensor hallux longus and toe flexors.
Skin condition: Presence and localisation of callosities or ulcerations and area of tenderness, often under the 1st metatarsal head or fifth metatarsal head and in the outer part of the feet.
Pain: Assess the site, timing (onset and chronicity), nature (eg, neuropathic or musculoskeletal) and intensity (eg, Visual Analogue Scale).
Assessment of foot and ankle flexibility:
Passive movement of the ankle into dorsiflexion, to assess the available range and stiffness. Observe with a straight knee to assess gastrocnemius length and bent knee to assess tendo Achilles/soleus length.
Lunge test: In-step standing (with upper limb support for balance), ask the patient to put their weight on the back leg and keep the heel on the ground while moving their hips forward. Observe with a straight knee to assess gastrocnemius length and bent knee to assess tendo Achilles/soleus length. Observe the angle of the tibia to vertical.
Passive movement of the hindfoot (calcaneal valgus/varus), mid-foot (pronation/supination) and forefoot (metatarsal dorsiflexion/plantarflexion). Is the position fixed or passively correctable? Can the hindfoot be corrected to a neutral position?9
Flexibility of the toes: passive movement of the metatarsal-phalangeal, proximal and distal interphalangeal joints to assess for flexible and fixed deformities.
Coleman block test: Place a block laterally under the hindfoot and allow the plantar flexed first ray to hang off the side of the block. This accommodates for the plantar flexed first ray, and any hindfoot deformity secondary to the forefoot deformity will correct. A positive Coleman block tests occurs when the calcaneus corrects to a valgus position and indicates a flexible hindfoot.54 It may also be assessed with the patient seated and the examiner manually reducing the hindfoot.15
The Foot Posture Index (FPI): Assessed in standing, using bony landmarks to allocate a score between −2 and +2 to each of six criteria related to foot posture. The aggregated score ranges from −12 (highly cavovarus) to +12 (highly planovalgus).55 56
Investigations arranged by orthopaedic surgical team:
X-ray to assess alignment and evaluate associated degenerative changes.
Weight-bearing CT scan: Cone-beam weight-bearing CT scan to assess foot under physiological load (used in some centres for the primary assessment and for preoperative planning).
MR scanning can be used to evaluate for arthritic change.55
Management
Management of foot deformities requires a multidisciplinary approach and must be centred throughout on the patient’s priorities and preferences (figure 2). The first line for milder and correctable deformities is conservative management, for example, stretching, mobilisation and orthotics. These approaches are often best led by physiotherapists, orthotists and podiatrists, and their early involvement is key. An early surgical opinion can help the team to understand the options for intervention and the optimal timing for surgery. Clinical nurse specialists and occupational therapists are well placed to support patients in planning for their postoperative recovery and their equipment needs, and to help them in considering their family needs and changes to occupation during a possibly prolonged recovery period. Groups and peer sharing of experiences can also reassure patients, helping with their decision-making on proceeding with surgery plus additional postoperative considerations.
Algorithm of decision-making for management of foot and ankle deformity for patients with CMT. CMT, Charcot-Marie-Tooth; FPI, Foot Posture Index; MMT, manual muscle testing; ROM, range of motion.
Conservative interventions
Exercise
There has previously been controversy that strengthening of the weaker, distal muscles for people with CMT may cause overwork weakness. However, recent studies of resistance training of distal muscles in people with CMT have shown reassuring evidence of improved strength without detrimental effects25 26 Importantly, improvements occurred in muscles that scored 4 out of 5 for strength (MRC, Manual Muscle Testing Score). Thus, strengthening muscles with mild weakness could be an important early strategy to address muscular imbalance through targeting key muscle groups, for example, ankle evertors and dorsiflexors.
Soft tissue management
Stretching exercises are a routine part of multimodal rehabilitation programmes27–29 but their effects have been specifically studied only in children.30 Maintaining range of motion of foot and ankle through regular stretching of the Achilles tendon and plantar fascia has some rationale as they are implicated in the evolution of foot deformities21 so there may be potential to avoid fixed deformity at an early stage. Teaching people how to stretch and self-mobilise the joints of the foot and ankle independently can also help with self-monitoring of the flexibility and condition of the feet.
Orthotics
Orthotic interventions can improve gait and balance for people with CMT through one or more the following biomechanical aims:
Redistribution of pressure under the foot.
Realignment and correction of foot deformities.
Reduction of foot drop.
Stabilisation of the ankle joint.
Increasing sensory feedback to the foot and/or ankle.
Redistribution of pressure and realignment of the foot and ankle can both reduce pain and reduce the risk of ulceration and skin breakdown. Supporting and stabilising the ankle joint can improve gait and balance function. Evidence for orthotic interventions is not clear due to a huge variety of custom-made or off-the-shelf lower limb orthoses, with only a small number tested in small, often uncontrolled studies. Scheffers et al,31 in a study of children with CMT, proposed considering prescription algorithms to match devices with specific biomechanical effects with the patients’ presenting impairments. This is a pragmatic way of managing this issue, but such prescription algorithms need careful development and testing as an intervention in their own right.
Existing evidence supports the using in-shoe foot orthoses to reduce pain and redistribute pressure in CMT, but less on the realignment of foot deformities.32 Several small studies have shown a positive effect on gait and balance when foot drop is supported by ankle foot orthoses of different types.33–37 There is limited evidence to ascertain overall effect,38 39 but there is potential that needs exploring in a more pragmatic way to resemble real-life, individualised prescription.31
Recommended best practice is for clinicians to review any devices prescribed with appropriate outcome measures, depending on the aim of the device.10 People with CMT may be reluctant to accept orthoses,34 40–42 so including consideration of the person’s opinion in decision-making will help to ensure prescription of devices that are acceptable to that individual. Measures of comfort should also be recorded over time, as ill-fitting splints may also lead to their non-use.42
Table 1 summarises examples of orthotic devices that are commonly prescribed for people with CMT disease.
Examples of orthotic devices that are commonly prescribed for people with Charcot-Marie-Tooth disease and the indications for prescription
Principles of surgery
The type and extent of the deformity in CMT dictates the subsequent surgical management.
Assessing whether the deformity is flexible or rigid and if there are associated degenerative changes is key to the initial decision-making. Whether the foot is flexible or rigid, the basic goals of surgery are the same: ‘To place the foot under the ankle, and the foot flat to the ground’.
To bring the hindfoot out of varus and position the heel under the ankle.
To bring up the first metatarsal to be level with the others where possible, to prevent the forefoot driving the hindfoot back into varus.
To balance the tendons to prevent recurrence.
Hindfoot varus
If the deformity is flexible/correctable, the bones can be realigned without fusing the joints. In this situation, the heel can be brought outwards with a lateralising calcaneal osteotomy. The posterior weight-bearing portion of the calcaneus is shifted outwards to a neutral position, which also moves the medial, varising force of the gastrosoleus complex laterally. This is an established procedure and there is broad consensus on its use (figure 3A).11 15
Hindfoot varus correction. (A) Possible incisions used for a lateral displacement calcaneal osteotomy (extended lateral approach). The calcaneal is then divided, and the tuberosity moved laterally and fixed with screws. (B) A wedge of bone is removed from the base of the first metatarsal. The opening is then closed, and the bone fixed. This elevates the first metatarsal.
If the hindfoot varus deformity is rigid/fixed, or arthritis of the joints due to abnormal loading and wear, or the deformity is too severe to be managed by joint preserving methods, patients may require a hindfoot fusion to bring the heel outwards.15 43 This is usually accomplished by a double (subtalar and talonavicular) or triple (also calcaneocuboid joint) arthrodesis.44 These are joint sacrificing procedures to create a plantigrade foot. Function is usually maintained and superior to that of an incomplete correction in joint sparing surgery.44
Patients with advanced ankle deformity and associated ankle arthritis may also need an arthrodesis of the ankle.11 However, such patients must be counselled regarding the degree of stiffness experienced if the ankle and the hind foot are all fused.
Forefoot cavus
Increased height of the longitudinal arch may be specific to the first metatarsal (due to the overpull of the peroneus longus) or more global affecting all the forefoot.
If only the first metatarsal is plantar flexed, this can be managed with a dorsiflexion osteotomy of the first metatarsal base,11 where a dorsally based wedge of bone is removed from the base of the metatarsal; as it is closed, it brings the metatarsal upwards (figure 3B).
If the cavus deformity is more global, and the whole forefoot is plantarflexed, just elevating the first metatarsal will not help. In this instance, a wedge may need to be removed from the midfoot (wedge tarsectomy). There are many variations, depending on where the apex of the deformity is. As a rule of thumb, where more than the two medial metatarsals require a dorsiflexion osteotomy, a midfoot osteotomy is indicated.7
Muscle balancing
It is insufficient to carry out bony procedures alone. Soft tissue correction with tendon transfers is required to balance the foot and prevent recurrence, as the deformity is dynamic.45 The type of tendon transfer required depends on the nature of the muscular imbalance and is patient specific.
A common procedure is the tibialis posterior tendon transfer. The strong tibialis posterior muscle is usually the primary deforming force in people with CMT; its antagonist is the weakened peroneus brevis. It inserts into the navicular bone, acting to plantarflex and invert the hindfoot, as well as to stabilise the medial longitudinal arch. Surgically, it may be released from its insertion and passed through the interosseous membrane to the dorsum of the foot, where it can turn from a powerful hindfoot invertor into an ankle dorsiflexor and hindfoot evertor (figures 4 and 5).45 This procedure was recommended at the ENMC workshop, for patients with severe foot drop but a flexible varus hindfoot.11 15
Tibialis posterior tendon transfer procedure. (A) Typical incision to release the tibialis posterior tendon from the medial aspect of the foot. The tibialis posterior tendon has been released from its insertion. (B) The tendon is brought out higher up the medial aspect of the leg. (C) The tendon is then moved to the outer aspect of the leg, in this case through the interosseous membrane. (D) The box on the top of the foot shows where this tendon is to be inserted to, into the lateral cuneiform in this instance. This enables the tendon to dorsiflex and evert the foot. (D) The tendon has been brought out through the incision on the top of the foot. (F) The tendon has been fixed into the lateral cuneiform using a screw called a biotenodesis screw.
Representation of main tendons involved in the muscular imbalance in CMT foot deformity. (A) From the medial side, shows the tibialis anterior tendon at the front, which inserts underneath the first metatarsal and functions to dorsiflex the ankle. This is weak and is overpowered by the peroneus longus, which is the more posterior of the two tendons in (B), which runs underneath the foot and inserts underneath the first metatarsal and functions to bring the metatarsal down. The net result is a plantarflexed first metatarsal and a high arch (cavus). The more posterior of the tendons in (A) is the tibialis posterior tendon, which predominantly inserts on the navicular and functions to invert the hind foot. This is stronger than its antagonist, the peroneus brevis, which is the anterior of the two tendons in (B) and inserts on the base of the fifth metatarsal and functions to evert the foot. The net result is an inversion of the hindfoot (varus). The tendon transfers aim to reduce hindfoot inversion by transferring the powerful tibialis posterior, and to reduce first-ray plantar flexion by attaching the peroneus longus to the peroneus brevis. The figure was created with app Complete Anatomy by 3D4Medical, from Elsevier.
Another commonly used tendon transfer in CMT foot surgery is the peroneus longus to brevis transfer. This essentially uses the strong peroneus longus, which pulls the first metatarsal down, to supplement the weak evertor of peroneus brevis.15 46 This can correct a forefoot-driven cavovarus deformity.
Ancillary procedures
Soft tissue releases
Where the cavovarus is long-standing, the subtalar and talonavicular joint capsules are contracted, causing deformity. Surgical release of the soft tissues alongside corrective bony procedures increases the correction achieved. The approach for the tibialis posterior tendon transfer allows access to the joint capsules, which may be released alongside the spring ligament.15
Achilles tendon and gastrocsoleus releases
A varus position of the hindfoot often leads to a tight Achilles tendon or gastrocnemius muscle and vice versa. This can be identified during the clinical assessment and can be addressed with either an Achilles tendon lengthening procedure or gastrocnemius recession, respectively. This is generally carried out before the bone and soft tissue procedures to improve dorsiflexion.
Plantar fascia release
This is commonly contracted because of the long-standing cavus deformity, the cavus foot shape reducing the distance between the anterior and posterior foot. Complete release of the plantar fascia, where it inserts into the posterior calcaneal tuberosity, can reduce the foot cavus. Isolated plantar fascia release is not recommended11 15
Lateral ligament reconstruction
Following bony correction, the lateral ligaments of the ankle may be assessed and reconstructed if required. This procedure is best carried out as part of the cavovarus correction rather than in isolation for ankle instability, due to risk of failure if the underlying malalignment is not corrected.47 48
Forefoot and toes
Clawing of the great toe can be addressed by transferring the overpowering extensor hallucis longus to the metatarsal neck, enabling the extensor hallucis longus to stop pulling the toe upwards as part of the clawing, so pulling the plantarflexed metatarsal head upwards. It is done alongside a great toe interphalangeal joint fusion as otherwise detaching the extensor hallucis longus would cause the toe to be bent. This is termed a Jones procedure.11 49
Where the long toe flexors are contracted, with worsening clawing deformities of the lesser toes as the foot is moved into a plantigrade position, they may be tenotomised. The lesser toes may also be realigned with extensor digitorum longus transfers to the metatarsal necks, so reducing the deforming force and improving ankle dorsiflexion.15
Indications and timing for surgery
Currently, there are no specific guidelines or randomised controlled trials on timing of surgery or types of patients to be referred to surgery.11 Current evidence is based on small case series. The ENMC workshop agreed that adult patients should be referred for surgical opinion after exhausting conservative measures, when the deformity has become rigid and is not correctable by orthotic devices and when there is a risk of developing musculoskeletal injury from foot deformities (figure 2).
While non-operative management may be appropriate, delaying surgery could cause the procedure to be more technically challenging with greater deformity correction required. Muscular imbalance during growth leads to increased rigidity of the deformity. This is initially secondary to shortening and fibrosis of the muscles; and later due to degenerative joint changes.25 26 Early disease may be managed with soft tissue corrective procedures and osteotomies, whereas later disease is likely to require complex arthrodesis procedures.27
Early surgical intervention may minimise the progression of the cavovarus deformity9 with evidence suggesting that corrective procedures while the foot is flexible lead to better outcomes. Ward et al 50 retrospectively assessed 25 CMT patients who had corrective surgery with a mean follow-up of 26.1 years. They compared those who underwent soft tissue procedures and osteotomies with patients in a separate study who were treated with triple arthrodesis at a similar age, showing lower rates of degenerative changes and reoperations. No patient required a triple arthrodesis.50
Alternatively, weakness progresses slowly over time, such that intervening early may lead to the need for revision surgery. It is, therefore, essential to be patient specific, considering the deformity, progression, symptoms and social factors. This can be a complex decision made between patient, family, surgeon, neurologist and physiotherapist. The timing of surgery is highly individual, and the risks of surgery must be weighed up against the benefits of proceeding.
Surgery must be tailored carefully to the patient, with the right surgery done at the right time.51 Although there is a great heterogenicity of surgical procedures employed by surgeons in different centres, and in different countries,5 the ENMC workshop agreed that the decision on timing and type of surgery should be taken in a multidisciplinary team and would be advisable to be performed in specialised centres.
Postoperative course
Postsurgical care
The aftercare following surgery varies between centres and countries.7 It is usual for a period of non-weight bearing immobilisation to allow the soft tissues and osteotomy sites to heal. Typically, this is 6 weeks for a flexible pes cavus correction procedure. For rigid deformities that require arthrodesis, there may be a 12-week period of immobilisation in a below-knee plaster cast. The increased immobilisation and protected weight bearing is required to ensure union of the arthrodesis; thus the first month is often non-weight-bearing, the second month is partial weight bearing, and the third fully weight-bearing.
Postoperative rehabilitation
There is little evidence regarding postoperative rehabilitation in CMT patients undergoing foot surgery. Rehabilitation is specific to the individual, the surgical techniques they have undergone, their underlying CMT presentation, level of function and any other comorbidities. Rehabilitation should be milestone based, recognising that patients progress at different rates following surgery. For both flexible and rigid pes cavus surgery, initial rehabilitation input while on the ward includes ensuring safe and independent mobility and function for discharge home, considering any weight-bearing restrictions. Once the period of foot and ankle immobilisation is complete, further input can usually start.
For flexible pes cavus correction, we present physiotherapy rehabilitation guidelines (table 2). The timescales for each phase are suggested while recognising that it may be longer than this for some patients (www.rnoh.nhs.uk/services/rehabilitation-guidelines). For rigid pes cavus surgery (subtalar, double or triple fusion) with no other techniques performed, patients may not need specific referral for physiotherapy rehabilitation. However, if there are issues identified such as difficulty with mobilising, impaired balance or function, or inclusion of additional surgical techniques, then physiotherapy input may be indicated. Once they are out of the immobilisation stage, interventions may include optimising range of movement for unfused joints, strengthening exercises, stretches, gait re-education, progression of mobility and walking aids, balance and proprioception work, advice and education and progression of function.
Physiotherapy rehabilitation guidelines for patients undergoing flexible pes cavus correction, for example, osteotomies, tendon transfers and other soft tissue techniques
Expected outcomes and complications
Outcomes for corrective surgery have been assessed in several studies, although most of these are retrospective. A study by Leeuwesteijn et al retrospectively assessed 33 CMT patients who had undergone soft tissue surgery and first-ray dorsiflexion osteotomy for cavovarus deformities. They looked at the long-term results with a mean follow-up of 56.9 months (range 13–153 months with no major complications identified. Significant improvements in pain, disability and foot function were reported, measured using the Foot Function Index. In 2 feet, triple arthrodesis procedures were required for recurrence after 37 and 64 months.52
Tejero et al retrospectively looked at 46 patients over a 6-year period who underwent deformity correction surgery. They included flexible and rigid deformities that were managed with either joint-preserving or joint-sacrificing surgery. There was a significant improvement in the Foot and Ankle Disability Index as well as functional improvement as measured with the short form 12 for both of these surgical groups at 12 months postoperatively. There was more improvement in the joint sparing group and a reoperation rate of 15.3% (8/52), mostly for recurrence. Postoperatively, there was one case of infection, three cases of painful callosity formation and three cases of lateral border overloading.53 Faldini et al prospectively reported on 12 patients in which 24 feet were operated on with 6 years of follow-up. A combination of soft tissue and corrective osteotomies was used with no intraoperative complications. The mean Maryland Foot Score increased from 72 preoperatively to 86 postoperatively with results rated as excellent in 50% cases (12 feet) and good in 42% cases (10). Postoperatively, there were two cases of wound dehiscence.7
A prospective study of 25 cases by Ramdharry et al 14 followed up in a specialist clinic and undergoing surgical treatment by a dedicated foot and ankle surgical team using joint sparing and arthrodesis procedures. They showed significantly improved alignment measured using the foot posture index (p=0.0001) and improved pain measured on the visual analogue scale (p=0.014). There was also a significant improvement in the patient-reported outcomes using the Manchester-Oxford Foot Questionnaire and in the number of plantar callosities. The study also showed a trend of a reduction in the number of falls postoperatively. The improvements were observed after 1 year of surgery and maintained up to 4 years of the study follow-up period.14 Patients undergoing surgery reported no major complications. In eight cases, there were wound concerns including blistering, superficial wound infections and delayed healing. In two cases who underwent ankle fusion, there was one case of Charcot neuropathy and one periosteal reaction. Another prospective study of 21 children and adolescents, with a mean age of 12.5 years, explored outcomes of surgery for cavovarus foot deformities treated by a single surgeon linked to a specialist children’s centre in Australia. A combination of soft tissue procedures and corrective osteotomies showed similar results. Mean duration of follow-up was 16 months (range 8–30 months). Participants were systematically assessed before and after surgery, as in Ramdharry et al study. There was significant improvement in alignment (FPI p=0.001), ankle dorsiflexion range and in self-reported symptoms, including daily falls (p=0.016). They did not report any major complications, except for a case of chronic regional pain syndrome that resolved at 12 months.13 In both studies, there was no significant improvement of strength and balance, mirroring the natural course of the disease.
Conclusion
Foot deformities are common in CMT, affecting quality of life through pain, falls, unsteadiness and ulcers. Conservative management is the first-line treatment for milder and correctable deformities and patients should be referred for a surgical opinion after failing of conservative measures. Ideally, the management should be provided through a multidisciplinary approach involving neurologists, allied health professionals (eg, physiotherapists, orthotists) and orthopaedic surgeons to establish timing and type of surgery.
Key points
Foot and ankle surgery is frequently performed to correct foot deformities in people with Charcot-Marie-Tooth disease; however, approaches vary and there are no evidence-based guidelines.
Conservative management is the first-line treatment for milder and correctable deformities.
Adult patients should be referred for surgical opinion after conservative measures have failed, or when the deformity has become rigid and not correctable by orthotic devices.
A multidisciplinary approach involving neurology, physical therapy and orthopaedic surgery is ideal to provide guidance on when to refer for surgical opinion and when to intervene.
Further reading
Reilly MM, Pareyson D, Burns J, et al. 221st ENMC International Workshop: Neuromuscular Disorders. 2017;27:1138–42.
Ramdharry G, Singh D, Gray J, et al. A prospective study on surgical management of foot deformities in Charcot Marie tooth disease. J Peripher Nerv Syst. 2021;26:187–92
Guyton GP. Current concepts review: Orthopaedic aspects of Charcot-Marie-Tooth disease. Foot Ankle Int. 2006;27:1003–10. https://doi.org/10.1177/107110070602701125
Data availability statement
Data sharing not applicable as no datasets generated and/or analysed for this study.
Ethics statements
Patient consent for publication
Ethics approval
Not applicable.
Acknowledgments
ML is grateful to the National Institutes of Neurological Diseases and Stroke and office of Rare Diseases (U54NS065712) and CMTUK for their support. This research was also supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre.
References
Footnotes
Contributors ML drafted manuscript, edited and reviewed final version. JBarnett drafted manuscript and provided figures. JBenfield drafted table on postsurgical rehabilitation. GR drafted manuscript, contributed to assessment section and led section on conservative management, created figure and table. MJW drafted manuscript and provided figures.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Commissioned; externally peer reviewed by Davide Pareyson, Milan, Italy.