Cavus Foot: Overview
Cavus foot is a deformity characterized by an abnormally high medial arch of the foot. It is typically classified into different types based on its cause, which can range from neuromuscular conditions to congenital, idiopathic, or traumatic processes. The condition can be progressive, and when left untreated, it may lead to further complications such as stiffness, pain, and dysfunction, severely impacting a patient’s quality of life.
Biomechanics of Cavus Foot
The deformities observed in cavus foot include the elevation of the medial arch, a varus hindfoot (inward tilting of the heel), and high-pitched midfoot. These abnormalities can affect the functioning of the foot during walking or running. The foot’s structure changes throughout the gait cycle: from the initial heel strike to the stance and swing phases. The Chopart joint’s locking and unlocking mechanism, essential for flexibility, can be disrupted in cavus foot. As a result, the foot remains rigid, reducing its shock-absorbing ability during movement.
Etiology of Cavus Foot
Cavus foot often results from muscle imbalances, where certain muscles overpower others. Neuromuscular disorders are the primary cause of cavus foot in adults. Charcot-Marie-Tooth disease (CMT), a hereditary sensory-motor neuropathy, is the most common underlying condition. Other causes include spina bifida, cerebral palsy, poliomyelitis, and trauma like peroneal nerve injuries.
Classification of Cavus Foot
The classification of cavus foot includes:
- Neuromuscular – The most common, often caused by CMT or other hereditary conditions.
- Congenital – Present from birth, such as in clubfoot.
- Acquired – Resulting from injury or disease.
- Idiopathic – No known cause, often referred to as a subtle cavus foot.
Further classification also occurs based on the location of the deformity (forefoot, hindfoot, or mixed) and its flexibility (flexible, stiff, or rigid).
Clinical Evaluation
Physical examination plays a crucial role in diagnosing cavus foot. A patient’s medical history, including family background, is taken into account, as cavus foot can be hereditary. Common symptoms include:
- Unstable gait
- Ankle pain
- Plantar painful calluses
- Claw toe deformities
- Occasional knee and hip pain
Several diagnostic tests assist in identifying the deformity:
- Peek-a-boo sign – A clinical test where the heel is visible when standing.
- Coleman Block Test – Helps differentiate between forefoot- and hindfoot-driven deformities.
- Gait analysis – Helps assess how the deformity affects overall posture.
Radiological Evaluation
Imaging is essential to assess the true nature of cavus foot deformities:
- Weight-bearing radiographs help reveal deformities by measuring angles like Meary’s angle, talocalcaneal angle, and calcaneal pitch.
- CT scans provide three-dimensional views, offering a more accurate evaluation of the deformity’s structure.
- MRI can detect tendon tears or soft tissue abnormalities associated with cavus foot.
Management of Cavus Foot
Conservative Treatment
Initial treatment often involves non-surgical interventions:
- Orthotics – Custom-made insoles to redistribute pressure.
- Activity modification – Adjusting activities to reduce strain on the foot.
- Stretching programs – Focused on the gastrocnemius and Achilles tendons to prevent further deformity.
However, conservative treatments may not suffice in the long run, especially in progressive or rigid cases.
Surgical Treatment
Surgical options are explored when conservative treatments fail, aiming to restore foot alignment and relieve symptoms. The goal is to achieve a functional, pain-free foot. Surgical procedures may include:
- Soft Tissue Release – To release contracted muscles and tendons.
- Osteotomy – A bone surgery to correct deformities, such as the first metatarsal dorsiflexion or calcaneal osteotomy.
- Arthrodesis – A fusion of joints, particularly in severe cases where other procedures fail.
Surgical plans are highly individualized based on the specific needs of the patient, the type of deformity, and its severity.
Conclusion
Cavus foot is a complex condition that can result from various causes, most notably neuromuscular disorders like CMT. Early and accurate diagnosis is critical in managing the condition effectively. While conservative treatments can help manage symptoms, surgical intervention is often necessary for severe cases, with a combination of soft-tissue and bone procedures required to correct the deformity. Advances in surgical techniques, including 3D printing for osteotomy planning, hold promise for improving outcomes in cavus foot surgery.
Dr. Mo Athar
