➢ Cavovarus foot deformity involves plantar flexion of the first ray relative to the hindfoot (cavus) due to progressive muscular imbalance. A plantar-flexed first ray drives the calcaneus into inversion (varus).
➢ The prototypical disorder for understanding the pathomechanics of cavovarus feet is Charcot-Marie-Tooth disorder (or the hereditary motor and sensory neuropathies [HMSNs]).
➢ Cavovarus foot deformity comprises a spectrum of anatomical and clinical deformities, and treatment must be individualized to include combinations of soft-tissue releases, osteotomies, tendon transfers, and salvage procedures.
➢ Joint-sparing procedures should be performed on skeletally immature patients whenever possible, although arthrodesis has been reported to have good long-term results.
➢ To our knowledge, there are no studies on the natural history of untreated cavovarus feet.
The cavovarus foot is a complex deformity involving a spectrum of changes to the hindfoot, midfoot, forefoot, and ankle. While cavovarus deformity can occur secondary to many congenital, neurological, or posttraumatic causes, the prototypical form is that of Charcot-Marie-Tooth (CMT) disease, the most common inherited neuropathy.
The first known cases of cavovarus foot deformity were reported by Aran in the Archives Générales de Medicine in 18501. Professor Jean Martin Charcot and his student Pierre Marie coined the term “peroneal muscular atrophy” in 1886, with clinical descriptions of distal muscle weakness beginning in the legs and hands2. Howard Henry Tooth, in his Cambridge MD dissertation in the same year, wrote on “the peroneal type of progressive muscular atrophy” and provided illustrations of hindfoot varus and wasting of the peronei and foot extensors (Fig. 1)3. Charcot-Marie-Tooth disease has now become synonymous with the hereditary motor and sensory neuropathies (HMSNs), of which nearly fifty genetic subtypes have been described4. These neuropathies constitute a genetically and phenotypically heterogeneous group of peripheral nerve disorders that are characterized by distal muscle wasting, often resulting in foot deformity. There are many causes of muscle imbalance and cavovarus other than Charcot-Marie-Tooth disease, including posttraumatic causes, clubfoot deformity, poliomyelitis, and spinal cord lesions.
Cavovarus is the most common foot deformity among HMSNs, is typically associated with HMSN I (demyelinating type), and commonly requires osseous or salvage surgery during development5. It was not until the 1950s that surgical treatment became widely accepted for correcting or preventing disability in patients with Charcot-Marie-Tooth disease6. Treatment of the cavovarus foot demands attention to the underlying etiology, skeletal age, and static and dynamic examination. Beals and Nickisch7 noted that the ability to understand the complex genetics of Charcot-Marie-Tooth disease and cavovarus feet has not been met with commensurate sophistication in treatment. A principle-based approach should be employed that incorporates the deformity flexibility, eschews oversimplified “recipes,” and appreciates the lack of evidence for almost all surgical procedures.
Terminology and Pathomechanics
The foot is anatomically divided into the forefoot, midfoot, and hindfoot, and compound word descriptions (e.g., “cavovarus,” “equinovarus,” “planovalgus,” etc.) each connote abnormalities of separate foot segments. Unfortunately, the nonsystematic employment of these descriptors serves as a source of confusion. In the cavovarus foot, the forefoot is in plantar flexion (or equinus) and valgus relative to the hindfoot (with the subtalar joint in neutral), although neither descriptor is part of the overarching terminology. In a cavovarus foot, “cavus” refers to a high longitudinal arch that does not contact the floor. Any foot segment can be responsible for cavus, herein conceptualized as equinus of the forefoot relative to the hindfoot. This cavus can emanate from the first ray or the entire forefoot. Cavus emanating from the hindfoot due to a dorsiflexed calcaneus is properly termed “calcaneocavus” and is a separate anatomical and treatment entity8. The “varus” component of cavovarus refers to an inverted calcaneus, which compensates for the forefoot valgus. It is critical to realize that the first metatarsal head, fifth metatarsal head, and calcaneal tuberosity serve as a foot tripod during gait. Understanding the abnormal loading of these three areas allows the dynamics of the deformity to be understood.
Charcot-Marie-Tooth disease is the prototypical disorder for understanding the stepwise development of a cavovarus foot. Although there is a sequential development of pes cavus and varus, not every deformity exists in every patient, and many components can develop simultaneously, heterogeneously, or not at all (Fig. 2). Although Charcot-Marie-Tooth disease is considered a peroneal nerve atrophy, one familial observational study demonstrated peripheral denervation beginning with the tibial nerve9.
Denervation of the intrinsic musculature (tibial nerve) occurs first, followed by more proximal involvement of the digital extensors, peroneus brevis, and tibialis anterior9. Intrinsic denervation leads to plantar wasting, fibrosis, and contracture, which shorten the foot and the plantar fascia, elevating the longitudinal arch (Fig. 2, A through D). The relatively strong, bulkier, and spared peroneus longus10,11 plantar flexes the first ray against the weakened tibialis anterior, producing medial column equinus, foot drop, and compensatory cavus. A shortened foot also creates a mechanical advantage for the peroneus longus against the tibialis anterior12,13. The extrinsic toe extensors attempt to compensate for tibialis anterior insufficiency in swing phase by dorsiflexing against weakened intrinsic muscles. This dorsiflexion drives the metatarsophalangeal joints into hyperextension and the toe interphalangeal joints into hyperflexion, creating a characteristic clawtoe deformity.
When the plantar-flexed first ray contacts the ground during stance phase, the hindfoot rolls into varus to restore the tripod. The relatively strong and spared tibialis posterior enjoys a mechanical advantage and deforms the hindfoot into further varus against a smaller and relatively denervated peroneus brevis. The Achilles tendon insertion migrates progressively medially, acting as yet another secondary hindfoot invertor. Hindfoot varus continually increases, tendinous mismatch increases, denervation progresses, and the deformity exacerbates in a positive feedback loop (Fig. 2, C through F). While hindfoot varus begins as a flexible deformity, it becomes rigid over time.
Normal function during the human stance phase is predicated on hindfoot flexibility into valgus, allowing shock absorption through mobile transverse tarsal joints. Hindfoot varus persistently locks transverse tarsal joints, leading to poor shock absorption, with resultant overload and stress fractures of the lateral aspect of the foot and concomitant translation of the tibiotalar contact point anteromedially14. Progressive deformity can cause medial compressive and lateral tensile overload throughout the entire ipsilateral extremity, even causing medial tibial stress fractures and iliotibial band syndrome15. Late findings can include laxity of the lateral ankle ligaments, fixed talar tilt, and progressive tibiotalar arthritis. Progressive sensory loss can result in Charcot arthropathy throughout the foot and ankle, which can further complicate the treatment of this complex condition.
The presentation of a cavovarus foot can encompass myriad complaints in the lower extremities. Assessment of birth and neonatal history, neuraxial abnormalities, neuromuscular conditions, and family history is essential. A unilateral cavus foot should heighten suspicion for a neuraxial abnormality such as a tethered cord, diastematomyelia, myelomeningocele, or other closed forms of spinal dysraphism.
Because of the presence of simultaneous deformities across foot segments, patients can present with complaints in many anatomical locations. In the forefoot, plantar metatarsophalangeal overload occurs secondary to tightening of the plantar fascia, metatarsophalangeal extension, and Achilles tendon contracture. Patients can complain of plantar metatarsophalangeal pain and callosity. Because of rigidity or overactivity, the midfoot experiences lateral foot overload, causing pain or stress fracture, particularly of the fifth metatarsal16. Hindfoot symptoms include painful retrocalcaneal bursitis, Haglund deformity resulting from Achilles tendon contracture, and subtalar osteoarthritis. The lateral ligamentous complex of the ankle is susceptible to tensile overload, failure, and peroneal tendinopathy, whereas the compressed medial aspect of the ankle is susceptible to arthrosis or osteochondral lesions.
Simple visual inspection of the foot, ankle, and leg provides important information with the patient in both non-weight-bearing and standing positions. When the patient is viewed from a lateral perspective, the cavus foot has a visibly elevated longitudinal arch that is out of contact with the floor, clawtoe deformity, and, sometimes, visible diastasis of the sinus tarsi. Substantial cavus can result in a plantar crease. When the patient is viewed from an anterior perspective, a “peek-a-boo heel”17 is a sign of early hindfoot varus; in addition, cavus and adductus usually can be grossly appreciated (Fig. 3, A). When the patient is viewed from behind, the heel is inverted (Fig. 3, B), the osseous lateral aspect of the ankle may be prominent, and the calf is atrophic. Non-weight-bearing inspection of the plantar aspect of the foot can reveal metatarsal head keratoses, muscular atrophy, or swelling from stress fractures (Fig. 4).
A detailed motor, sensory, and reflex examination should be performed for every patient. The most common presenting signs associated with CMT type-1A are areflexia and an inability to heel-walk18. Patients with Charcot-Marie-Tooth disease may develop equinus during swing phase and a steppage gait. Some authors have observed that patients with Charcot-Marie-Tooth disease have a so-called marionette walking pattern, in which compensatory pelvic shift, truncal rotation and bend, and circumduction are adopted to improve propulsion9. The rotational and coronal alignment from hip to ankle, which can contribute to or compensate for the foot deformity, should always be assessed. As many as 25% of adult patients can have late-onset sensory loss, which is milder than motor loss19.
Examination of the heel cord by means of passive ankle dorsiflexion is mandatory. This examination may reveal ankle plantar-flexion weakness and ambulation in calcaneus gait or Achilles tendon tightness and toe-walking. The Silfverskiold test can be used to differentiate isolated contracture of the gastrocnemius20.
Coleman and Chesnut devised a simple test for assessing hindfoot flexibility; this test has become a cornerstone of evaluation of the cavovarus foot. In this test, the lateral aspect of the forefoot and the heel are supported on a one-inch block and the first metatarsal is allowed to drop to the ground (Fig. 5, A)21. Correction of a varus heel into valgus signifies flexible hindfoot deformity (and therefore preserved subtalar motion), whereas maintenance of heel varus signifies hindfoot rigidity. There appears to be variation in the performance of this maneuver, with some authors placing the heel on the floor instead of the block22,23. Others perform a prone evaluation as described by Price and Price (our preferred technique), a kneeling test, or an oblique block test (Fig. 5, B, C, and D)24-26. With the patient in a non-weight-bearing position, the talonavicular joint should be manually reduced (subtalar neutral) to assess subtalar movement. All maneuvers share the common goal of evaluating subtalar motion by attempting to incite hindfoot valgus.
Weight-bearing anteroposterior and lateral radiographs are essential for assessing the functional position of the foot. The talo-first metatarsal angle (Meary angle) on the lateral radiograph of the foot should be 0° to 5° (Fig. 6, A)27. An apex-dorsal Meary angle signifies forefoot equinus relative to the hindfoot and defines radiographic cavus. The intersection of the long axis of the talus and the first metatarsal is the apex of deformity and is the point at which maximum osseous correction is achieved with osteotomy. Also on the lateral radiograph, a wedge-shaped cuboid, a double talar dome sign (representing talar external rotation), and a so-called see-through tarsal canal are characteristic findings. If the calcaneal pitch is substantially greater than 30°, cavus may be secondary to calcaneal dorsiflexion and a potentially incompetent triceps surae. Attempts have been made to objectively measure other segmental deformities on lateral radiographs28, and a lateral Coleman block radiograph also has been described29. The anteroposterior radiographs may reveal medial peritalar subluxation, narrowing of the foot, metatarsal overlap, and a decreased talocalcaneal angle secondary to hindfoot varus (Fig. 6, B). These radiographic features occur because the talus externally rotates and the talonavicular articulation migrates cephalad to the calcaneocuboid joint, effectively locking the transverse tarsal joints.
A Harris axial radiograph of the heel can be used to assess calcaneal inversion and should be made if calcaneal osteotomy is planned. Clinical suspicion should trigger radiographs of the spine and/or pelvis as there are appreciable rates of coincidence of scoliosis (9%)30 and hip dysplasia31 in patients with Charcot-Marie-Tooth disease. Magnetic resonance imaging (MRI) of the spine should be requested in cases of unilateral cavus or spasticity. A computed tomography (CT) scan of the foot with three-dimensional reconstruction should be performed in cases in which severe malalignment precludes radiographic evaluation and also should be used to assess osteoarthritis during preoperative planning.
Many cavovarus feet are subtle and are left untreated in the absence of high demands or symptoms. To our knowledge, there are no studies on the natural history of untreated cavovarus, and there have been few investigations of nonoperative modalities32-34. Most studies on operative treatment have involved small numbers of patients with varied diagnoses, limited follow-up, and assorted surgical procedures6,25,27,29. In this evidence vacuum, a principles-based approach should be employed. Goals include mitigation of symptoms, maximization of forefoot contact, and alignment of the forefoot and hindfoot.
Thoughtful planning can lead to the achievement of these goals if one considers the wide spectrum of clinical presentation, the individualized examination, and skeletal maturity and immaturity. Because no two cavovarus feet are identical, rigid treatment algorithms should be approached with caution. With operative treatment, contractures should be released, deforming tendinous vectors should be functionally realigned, osteotomies are preferred over arthrodeses of non-arthritic joints (particularly in pediatric patients)23,35, and the ankle joint reaction force and functional axis of the Achilles tendon should be centralized. Procedures should be performed in a single stage whenever possible. The timing of surgical treatment remains controversial as early treatment of a progressive deformity could prevent later degenerative changes36.
Studies of nonoperative treatment of cavovarus feet have investigated rehabilitation, bracing, and so-called orthopaedic shoes24,32-34. In cases of flexible deformity, an orthotic with a recessed first ray and lateral foot post can stabilize the forefoot and prevent hindfoot varus during stance (Fig. 7). Pain relief may result from the redistribution of abnormal plantar pressures37. Lace-up braces can be used to stabilize hindfoot varus by controlling the supramalleolar region of the ankle and can be a first-line treatment for lateral ankle sprains in patients with flexible cavovarus. Patients with foot drop can be managed with ankle-foot orthoses and night bracing to stretch tight heel cords. Those with clawtoe deformity benefit from extra-depth and wide-toe box shoes and plantar metatarsal pads. Rigid hindfeet are unlikely to respond to bracing and are at risk for skin breakdown when treated with a rigid orthosis.
The operative treatment of cavovarus feet depends on the mobility of the subtalar joint, as assessed with a Coleman block examination or its variations. Classic surgical treatment for a flexible hindfoot involves forefoot and midfoot osteotomies to realign cavus, often in combination with tendon transfers to mitigate deforming forces. A flexible varus hindfoot should correct into valgus after forefoot realignment. The role of soft-tissue surgery, alone or in combination with osteotomies, and the anatomical principles behind each procedure have been subjects of debate25. Rigid hindfoot deformity involves similar forefoot and midfoot procedures for the treatment of cavus in addition to calcaneal osteotomy or arthrodesis. Intraoperatively, the surgeon determines the degree of correction of the hindfoot and forefoot to obtain neutrality.
As intrinsic atrophy and plantar fascial contracture contribute to cavus deformity, plantar fascial release can be performed in either flexible or rigid feet. This procedure improves foot shortening by allowing dorsiflexion of the first ray. The necessity of plantar fascial release has been debated, with some authors advocating open release in every patient38 and others reporting good results with plantar fascial release in <25% of patients (even in rigid cavovarus)25. The necessity of plantar fascial release likely depends on the net lengthening effect of any medial-column osteotomies. If there is length neutrality or even net shortening after such procedures, an argument can be made against plantar fascial release as its tension effects on the arch may be relieved. We routinely perform open plantar fascial release with relative lengthening osteotomies of the medial column at the apex of deformity. A small longitudinal or transverse incision at the plantar fascial origin is used, with careful protection of the medial and lateral plantar branches of the tibial nerve.
As described above, the Achilles tendon becomes a secondary hindfoot invertor with progressive heel varus. Despite its deforming force, many authors have asserted that the Achilles tendon is not routinely contracted in cavovarus feet and should not always be treated22. Certainly, overlengthening of the Achilles tendon will diminish push-off23. Iatrogenic weakening of the triceps surae should be avoided8,28. We routinely perform forefoot or midfoot osteotomies to correct foot equinus and only correct equinus at the ankle on the basis of the results of a Silfverskiold test with the patient under anesthesia. In the case of a severely contracted hindfoot, an open posteromedial release and Achilles tendon lengthening may even be needed to correct hindfoot varus and to prevent forefoot overload.
Osteotomy and Arthrodesis of the Forefoot and Midfoot
Many forefoot and midfoot osteotomies are available for the correction of cavus with the object of elevating the first ray, allowing a plantigrade tripod to contact the floor with the heel in valgus (Fig. 2). In general, osteotomies are performed after soft-tissue releases (plantar fascia, Achilles tendon, subtalar or talonavicular joint capsules) but before the tensioning of any tendon transfers. The indications for a medial column osteotomy include a painful first ray, metatarsalgia resulting from forefoot equinus, forefoot-driven hindfoot varus, and inability to correct cavus with soft-tissue procedures alone. The apex of forefoot cavus is determined preoperatively on the basis of the Meary angle, and maximum correction will be obtained with an osteotomy at this location (i.e., realignment will be achieved without interfragmentary translation). The most common osteotomy types are a dorsal closing-wedge osteotomy of the first metatarsal base and a plantar opening-wedge osteotomy of the medial cuneiform (Fig. 8). Combining the two allows up to 60° of cavus correction25. The reported results in terms of pain, function, and satisfaction have been good at short to intermediate-term follow-up when dorsiflexion metatarsal osteotomies have been combined with other procedures39-41. After midfoot and forefoot intervention for the treatment of cavovarus feet, Chan et al.42 demonstrated that the findings of pedobarography were altered but did not normalize, with high heel pressure persisting despite radiographic correction. As forefoot plantar flexion can exist in any metatarsals, dorsiflexion osteotomies of the lesser metatarsals can be performed25. The relative lengths of the metatarsals should be kept in mind as potential transfer lesions can result. Such an approach for the treatment of flexible cavovarus may result in fewer long-term degenerative changes in comparison with triple arthrodesis43.
Medial-column correction can alternatively be obtained through arthrodesis of the talonavicular or naviculocuneiform joints. Thorough plantar and medial capsular releases are necessary for joint mobilization and arch correction. Articular cartilage is then denuded, and minimal bone cuts are utilized prior to realignment and fixation. Dorsal closing-wedge osteotomies spanning the talonavicular or naviculocuneiform joints can be utilized for the correction of substantial deformity but have a high rate of failure as a result of nonunion23,44. We prefer joint-sparing surgery for children as one overarching surgical goal is the prevention of chondral deterioration. Furthermore, arthrodesis before the age of twelve years in girls and fourteen years in boys may result in foot shortening45,46, although the functional importance of this finding is unknown. In adult patients, joint-sparing osteotomies and soft-tissue procedures have resulted in good clinical outcomes at short to intermediate-term follow-up35.
Calcaneal and Tibial Osteotomy
If the hindfoot is not correctable, subtalar motion has been lost and a calcaneal osteotomy is necessary to achieve hindfoot valgus in stance. Many technical variations exist, including a lateral calcaneal closing-wedge osteotomy47,48, pure lateralizing osteotomy44, or L or Z-type Italian osteotomies49,50, all of which purportedly decrease ankle joint contact pressures51. Hindfoot realignment further supports eversion and peroneus brevis function while mitigating the inversion moment of the tibialis posterior tendon. Lateralizing the calcaneus may cause fascial tensioning medially in the tarsal tunnel, with some authors advocating routine neurovascular decompression23,52. All calcaneal osteotomy types also share a common goal of lateralizing the functional axis of the Achilles tendon. Each technique provides differential amounts of hindfoot correction depending on cut geometry, with calcaneal shortening occurring after closing-wedge osteotomies53,54. Early and intermediate-term studies of lateralizing calcaneal osteotomies (almost always performed in combination with other procedures) have demonstrated good satisfaction and improved American Orthopaedic Foot & Ankle Society (AOFAS) scores, with restoration of hindfoot valgus and the medial longitudinal arch44,55.
Unlocking the subtalar joint also has been successfully reported in association with tibial osteotomies56,57. External tibial torsion or a varus tibia can exacerbate cavovarus alignment, and coronal and axial plane alignment proximal to the foot should be evaluated independently to ensure that all deformities are corrected in one setting. A medial-rotation-producing supramalleolar tibial osteotomy also has been suggested as a way to unlock an externally rotated talus before the performance of additional foot procedures56. Valgus-producing supramalleolar osteotomies may restore a normal tibiotalar contact point in cavovarus feet and have been suggested as an alternative to calcaneal osteotomy according to surgeon preference57, although no clinical follow-up data exist, to our knowledge. We prefer a lateralizing calcaneal osteotomy for the treatment of rigid hindfoot varus and only perform tibial osteotomy when the tibia is a primary source of deformity.
Arthrodesis and Salvage Procedures
Complete realignment of the forefoot and hindfoot can be accomplished by means of triple arthrodesis (arthrodesis of the subtalar, talonavicular, and calcaneocuboid joints). In adults, release of the talonavicular and calcaneocuboid joints (and spring ligament) may achieve correction without arthrodesis. Multiple long-term Level-IV outcome studies have revealed that triple arthrodesis for the treatment of cavovarus feet has been associated with high rates of adjacent-joint degeneration but wide ranges of patient satisfaction7,58,59. Wetmore and Drennan reported that 47% of patients with Charcot-Marie-Tooth disease had poor clinical results at fifteen years of follow-up after triple arthrodesis for the treatment of cavovarus and advocated using the procedure as a salvage procedure for the treatment of rigid feet only59. Angus and Cowell reported that triple arthrodesis was associated with clinical satisfaction at thirteen years, despite high rates of adjacent-joint degeneration, osteonecrosis, and recurrent deformity58. These findings were mirrored in a forty-four-year follow-up series of young patients who were managed with triple arthrodesis in which radiographic criteria bore no correlation with clinical outcomes, with a 95% rate of patient satisfaction despite a 100% rate of adjacent-joint degeneration at the time of the latest follow-up60. While those results were seemingly auspicious, only a minority of the initially managed patients returned for the latest follow-up, which may support the use of joint-sparing procedures in pediatric feet. Alternative salvage procedures for the treatment of rigid cavovarus feet have been proposed, including navicular excision and a cuboid closing-wedge osteotomy, with satisfactory results at five years of follow-up61. Clinical results are difficult to interpret in the absence of natural history studies, which would provide baseline rates of adjacent-joint degeneration in untreated cavovarus feet that could be used as a standard for comparison.
We utilize triple arthrodesis for the treatment of rigid cavovarus feet in skeletally mature patients with lower physical demands. At the time of arthrodesis, it is imperative to correct muscle imbalance in order to prevent recurrence of deformity through the tibiotalar joint. Isolated subtalar arthrodesis can be performed in some cases when forefoot deformity is thought to be minimal. Caution is urged when surgically creating a stiff foot that may lose protective plantar sensation secondary to a progressive peripheral neuropathy.
Tendon transfers can be performed to counter the deforming forces of cavovarus, namely, imbalance favoring the peroneus longus, tibialis posterior, and extensor hallucis longus. Any such procedure should adhere to the basic principles of tendon transfers, although donor morbidity is less concerning as collapse is less likely to ensue because of the underlying osseoligamentous cavus. The full menu of available transfers is complex, and indications have been described elsewhere23,46,62,63. We recommend carefully targeting specific recipient muscle weakness with a (preferably) in-phase or (alternatively) out-of-phase transfer.
Roper and Tibrewal, in a study of ten patients with Charcot-Marie-Tooth disease, reported that tendon transfers and soft-tissue surgery alone demonstrated good results at fourteen years of clinical follow-up, without the need for any subsequent triple arthrodeses64. An overactive peroneus longus can be treated with a longus-to-brevis transfer with or without osteotomies55. Hindfoot varus or foot drop can be mitigated with a full or split tibialis posterior transfer to the dorsum of the foot23,65,66. Postoperative gait analysis after tibialis posterior transfer, particularly ankle dorsiflexion in swing, suggests the occurrence of active substitution and not merely tenodesis67.
After surgical restoration of a plantigrade foot, toe flexion may resolve if the deformities are flexible, but many forefoot transfers have been described. A relatively spared extensor hallucis longus tendon can undergo a Jones transfer to the dorsal aspect of the first metatarsal (to aid the tibialis anterior in dorsiflexion with the goal of assisting the tibialis anterior by assisting in ankle flexion)68-70 or to the peroneus brevis or lateral aspect of the foot (promoting eversion)71. Flexor hallucis transfer to the metatarsal may correct toe clawing and may be combined with either the Girdlestone-Taylor procedure or interphalangeal joint arthrodesis for the treatment of lesser toe clawing, particularly in the adult population72,73.
Lateral Ankle Instability
Recurrent lateral sprains and peroneal tendinopathy can occur in association with chronic lateral foot overload and hindfoot varus. We prefer a surgical technique in which cavovarus malalignment is treated according to hindfoot flexibility and reconstruction of the lateral ankle ligaments is performed with a modified Broström technique when necessary55,74. The surgical goals in these cases are the prevention of chronic talar tilt and tibiotalar degeneration.
The cavovarus foot develops as a result of a series of characteristic deforming forces resulting from muscle imbalance. The HMSNs are prototypical for understanding sequential progression of deformity, which generally involves forefoot equinus causing hindfoot varus. No studies on the natural history of untreated cavovarus are available, to our knowledge, and the low level of evidence for the wide array of surgical options is a treatment challenge. The dynamic nature of progressive cavovarus mandates a careful treatment approach in which hindfoot flexibility is assessed and patient-specific forefoot and hindfoot deformities are targeted with a combination of soft-tissue procedures and osseous realignment. The goals of treatment are the restoration of a plantigrade foot and balance of deforming forces. Bracing, tendon transfers, and osteotomies are preferred for skeletally immature patients. After skeletal maturity, all of the above procedures may be used, or a triple arthrodesis with careful muscle balancing can achieve a plantigrade foot and mitigate recurrence. In the older adult, triple arthrodesis can achieve realignment and relief from osteoarthritis, whereas untreated severe cavovarus may progress to lateral ankle instability. Joint-sparing procedures should be favored whenever feasible, although long-term adjacent-joint degeneration after arthrodesis does not preclude satisfactory clinical outcomes.
Source of Funding: No external sources of funding were used in the composition of this manuscript.
Investigation performed at the Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. None of the authors, or their institution(s), have had any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. Also, no author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.
- Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated