The human foot is a remarkable feat of bioengineering, a complex structure designed to bear weight, absorb shock, and propel us forward with each step. Central to its function is the medial longitudinal arch, which acts as a natural spring. However, for a significant portion of the population, this arch is excessively elevated, a condition known as pes cavus, or simply, a high-arched foot . Affecting approximately 10% of the population, pes cavus is much less common than its counterpart, flat feet, but it is also far more likely to be a source of pain and disability . This condition is not merely a structural anomaly; it is often a complex manifestation of underlying neuromuscular imbalances that can significantly affect an individual’s mobility and quality of life.
Defining the Cavus Foot
Pes cavus is characterized by a hollow, raised instep that does not flatten with weight-bearing . This seemingly simple definition belies a complex deformity that can involve the forefoot, midfoot, and hindfoot in various combinations . The most common presentation is the cavovarus foot, where the high arch is accompanied by a heel that tilts inward (varus) . This configuration disrupts the foot’s normal tripod structure—where weight is evenly distributed among the heel, the first metatarsal head (ball of the foot), and the fifth metatarsal head. In a cavus foot, the first ray (the metatarsal and cuneiform bones) is often pulled into a permanently plantarflexed, or downward, position . This shifts the weight disproportionately onto the heel and the lateral border of the foot, leading to instability and pain .
Etiology: A Sign of a Deeper Problem
While some cases are idiopathic, meaning they arise without a known cause and remain stable over time, pes cavus is most frequently a sign of an underlying neurological condition . In fact, studies suggest that roughly two-thirds of patients seeking treatment for symptomatic pes cavus have an identifiable neurological abnormality . The bilateral presentation of the condition is highly suggestive of a hereditary or congenital source, whereas a sudden, unilateral deformity, particularly without a history of trauma, warrants immediate investigation for a spinal cord lesion or tumor .
The primary driver of neurological pes cavus is muscle imbalance. The most common associated disorder is Charcot-Marie-Tooth (CMT) disease, a hereditary motor and sensory neuropathy that causes progressive muscle weakness . In CMT, the anterior tibialis muscle (which dorsiflexes the ankle) and the peroneus brevis (which everts the foot) become weak. They are overpowered by their stronger antagonists: the peroneus longus, which pulls the first ray into plantarflexion, and the posterior tibialis, which pulls the hindfoot into varus . Other neuromuscular causes include cerebral palsy, Friedreich ataxia, poliomyelitis, and spinal dysraphism . Beyond neurological origins, pes cavus can also be a structural consequence of trauma, such as a malunited calcaneal fracture, or the residual effect of an untreated clubfoot .
Symptoms and Biomechanical Consequences
The symptoms of pes cavus are as varied as its causes, stemming directly from the altered biomechanics of the foot. The decreased weight-bearing surface area places immense stress on specific points, most commonly the ball of the foot, leading to metatarsalgia and the formation of painful calluses . The lateral border of the foot is also overloaded, often resulting in pain around the cuboid bone .
The varus tilt of the hindfoot makes the ankle joint chronically unstable, as it is predisposed to roll inward, leading to frequent and recurrent ankle sprains . Toe deformities are another hallmark of the condition. As the foot attempts to compensate for muscle weakness, the long extensor tendons are recruited to assist with dorsiflexion, leading to “clawing” of the toes—a hyperextension at the metatarsophalangeal joint and flexion at the interphalangeal joints . These clawed toes can rub against footwear, causing painful corns on the top of the toes. Patients often report difficulty fitting shoes, general foot fatigue, and pain with standing or walking .
Diagnosis and Evaluation
Diagnosing pes cavus begins with a comprehensive clinical examination and patient history. A physician will observe the patient’s gait, inspect the foot’s arch height, and look for callus patterns and toe deformities. The flexibility of the deformity is a key assessment. The Coleman block test is a crucial maneuver used to determine if the hindfoot varus is flexible and “forefoot-driven.” By placing the lateral side of the foot on a block, the plantarflexed first ray is allowed to drop, and if the hindfoot corrects to a neutral position, it confirms that the varus deformity is secondary to the forefoot and is not a fixed bony problem .
Further evaluation often involves advanced imaging. Weight-bearing X-rays are essential for quantifying the deformity through specific angles, such as the Meary angle and calcaneal pitch . To rule out an underlying neurological cause, a physician may order nerve conduction studies, electromyography (EMG), or even an MRI of the spine .
Treatment Strategies: From Conservative to Surgical
The primary goal of treatment for pes cavus is to achieve a plantigrade foot—one that rests flat on the ground—allowing for a stable, pain-free distribution of weight . Treatment is tailored to the individual, based on the severity of the deformity, its flexibility, and the underlying cause.
For mild to moderate, flexible deformities, non-surgical management is the first line of defense. Custom orthotic devices are the cornerstone of conservative care. Unlike simple arch supports, orthotics for pes cavus are designed to fill the arch, offload pressure points, and provide a lateral forepost or recess beneath the first ray to help balance the foot . Extra-depth shoes with a wide toe box can accommodate clawed toes and orthotics, while bracing, such as an ankle-foot orthosis (AFO), may be used to address foot drop or severe instability . Physical therapy focusing on stretching tight structures and strengthening weak muscles can also be beneficial .
When conservative measures fail to relieve pain or the deformity is rigid and progressive, surgical intervention is often necessary. The surgical approach is highly individualized, frequently combining multiple soft-tissue and bony procedures . Soft-tissue procedures include a plantar fascia release to alleviate the tight band contributing to the arch and tendon transfers, such as the Jones procedure, which transfers the extensor tendon of the great toe to the first metatarsal to correct clawing and improve dorsiflexion . Bony procedures, or osteotomies, are used to correct fixed deformities. A dorsiflexion osteotomy of the first metatarsal can correct a plantarflexed ray, while a calcaneal osteotomy can realign a varus hindfoot . In cases of severe, rigid deformity with arthritic changes, an arthrodesis (fusion) of the major joints of the hindfoot or midfoot, such as a triple arthrodesis, may be the best option to create a stable, plantigrade foot, though it is often reserved as a salvage procedure . Recent advancements, such as the use of Ilizarov external fixation for gradual correction, and 3D-printed guides for precise osteotomies, are improving outcomes for complex cases .
Pes cavus is a far more complex condition than a simple “high arch.” It is a biomechanical disruption with the potential to cause significant pain and instability throughout the foot and ankle. Crucially, it serves as a potential red flag for underlying neurological disease, making a thorough diagnostic workup essential. With a deep understanding of its pathophysiology and a range of treatment options from accommodative orthotics to sophisticated surgical reconstruction, clinicians can effectively manage this challenging condition, helping patients restore function and improve their quality of life.