What Is Cavus Foot?

Overview

Cavus foot, sometimes called claw foot, is a condition where the foot has an elevated arch appearance. It can develop in children and adults, and it affects 10% of the general population. Non-surgical and surgical treatments can be used to achieve a normal foot position for even weight distribution. With this in mind, this article will explore the causes, symptoms, and management options for cavus foot. 

Causes of cavus foot

Cavus foot deformity is caused by an imbalance between the muscles located on the inside and outside of the foot.¹ This imbalance is mainly attributed to various neurologic disorders. These include:

Progressive disorders: 

• Charcot-Marie-Tooth (CMT) disease - A group of inherited disorders that damage the peripheral nerves. These are nerves that transmit information and signals from the central nervous system (brain and spinal cord) to the rest of the body.³ 
• Friedreich's ataxia - An inherited condition that mainly affects the nervous system and the heart
• Brain tumour - A cancerous growth that can occur anywhere in the brain
• Spinal trauma - Damage to the cells and nerves that transmit and receive signals from the brain to and from the rest of the body as a result of trauma
• Syringomyelia - Rare disorder where a syrinx (fluid-filled tube-like cyst) usually develops in the cervical spinal cord region.⁴
• Duchenne Muscular Dystrophy (DMD)- An inherited disorder that causes progressive muscle wasting and weakness.

Static disorders: 

• Cerebral palsy - A group of lifelong disorders that affects movement and coordination, causing physical disability
• Stroke - A life-threatening condition that occurs when the blood supply to the brain cuts off
• Polio - A life-threatening condition caused by the poliovirus
• Peroneal nerve injury - This occurs when the nerve roots from the spinal cord become compressed, irritated, or damaged

Other possible causes include: 

• Tarsal coalition - Abnormal connection between two or more bones at the back of the foot
• Complications post-medical care/treatment. These include:
  • Infection
  • Nerve damage
  • The deformity returning 
  • Joint stiffness or persistent pain either in the joint or ankle
  • Wound healing issues, which can lead to infection 
  • Blood clots (cramping pain) that may form in the leg, known as deep vein thrombosis (DVT) 

• Genetic abnormalities - An individual can inherit genetic traits or mutations that may affect the development of their foot muscles, bones or nerves
• Scarring after compartment syndrome - An acute or chronic condition that occurs when there’s increased pressure inside a muscle, which restricts blood circulation

Signs and symptoms of cavus foot

The signs and symptoms of the cavus foot deformity vary among individuals; however, the most common symptom is the high arch of the foot. Other symptoms include:

• Lateral foot pain - This type of pain arises on the outer side of the foot due to an increase in pressure within this area. This may lead to fifth metatarsal fractures in this specific bone.
• Metatarsalgia - Pain in the forefoot (balls) of the feet.
• Plantar keratosis - Painful thickened skin on the soles of the feet.
• Ankle instability - Especially if the heel is tilted and the peroneus brevis muscle (a muscle located in the lower leg) is weak. This can make the ankle become susceptible to rolling or twisting, increasing the likelihood of ankle sprains.
• Weakness and fatigue - Particularly in individuals with underlying neuromuscular disorders.
• Foot drop - Weakness in the muscles of the foot and ankle.

Management and treatment for cavus foot

Non surgical treatment

It is recommended to explore non-surgical treatment for both neurological and non-neurological cavus foot deformity. These include:² 

Physiotherapy: This includes exercises to improve joint flexibility, stretching, and strengthening exercises for the foot muscles. Additionally, electrotherapeutic devices such as electrical currents or ultrasound waves for pain relief are sometimes used. 

Chiropody: These professionals may remove thickened skin on the soles of the feet.

Medication: Over-the-counter (OTC) pain medication such as paracetamol (Tylenol) and nonsteroidal anti-inflammatory drugs (NSAIDs) are used to decrease inflammation and pain in the foot.

Shoe modifications: This includes using orthotic devices (artificial supports), which can be worn in the shoe to maintain extra stability of the foot’s arch, distribute pressure more evenly, and enhance overall comfort and balance while walking or standing.

Surgical treatment

Cavus foot surgery is typically considered when the deformity is severe or getting worse. 

The goals of cavus foot surgery are to:

• Correct the cavus foot deformity 
• Achieve a pain-free and functional foot
• Preserve the foot joint 
• Adjust muscle strength and balance to improve walking 
• Prevent the deformity from getting worse

Currently, there are several surgical methods available, including: 

Soft tissue balance: Adjusting the muscles and other soft tissues around the foot to improve its alignment and function. 

Bone realignment (osteotomy): Surgically cutting and repositioning a bone to improve its alignment and correct deformities.

Joint fusion (arthrodesis): Surgically joining two or more bones together to create a solid, stable joint. 

External fixation correction (Ilizarov technique): A method that uses an external frame attached to the affected limb to gradually correct cavus foot deformities.

Complex deformities often require a combination of these methods in multiple surgeries.

In cases where cavus foot is caused by neurological disorders like a stroke or brain trauma with a short duration, surgery aims to rebalance the foot muscles and address soft tissue tightness. 

These surgical procedures include: 

Osteotomies (bone cuts): This procedure involves cutting the bones to correct the high arch and adjust the alignment of the bones in the foot.

Tendon transfers: During this procedure, the tendon is detached from its original attachment point and transferred to a different location to rebalance the muscles around the foot and ankle.

Ancillary procedures: These are additional surgical procedures performed in combination with the primary surgery (listed above). These procedures include soft tissue releases, ligament repairs, and joint capsule adjustments.

Diagnosis

To diagnose cavus foot, the doctor will perform a thorough physical examination and use imaging tests. 

They start by visually inspecting the patient's back for any signs of spinal issues. Then, they check the hips and knees for deformities and assess the range of motion. The patient’s foot is then examined further. 

During the foot examination, the healthcare professional will look for specific things. They observe the patient's gait (walking and balance) to see if there is an unstable foot drop, a weak push stance, or weak dorsiflexion (movement of the top part of the foot towards the shin). 

They also check the appearance of the feet and toes, looking for asymmetry and claw-toe deformities. The range of motion in the different parts of the foot, ankle, and toes is assessed, and the flexibility of the hindfoot (near the heel) is evaluated using the Coleman block test.

Radiological evaluation, including X-rays, provides additional information about the foot's structure and alignment. Advanced imaging techniques like CT scans or MRI may be used for a more detailed analysis. Gait analysis helps understand how the cavus foot affects the body's posture during walking.

In cases where a neuromuscular disorder is suspected, an electromyogram (EMG) can be performed to assess muscle strength and detect any nerve-related issues.

FAQs

How can I prevent cavus foot?

Because cavus foot is caused by a genetic, neurological, or underlying condition, it cannot be prevented. However, with proper monitoring and treatment, cavus foot can be managed successfully. 

How common is cavus foot?

It has been estimated that cavus foot affects 10% of adults.² It is less common than flat feet.

When should I see a doctor?

If you notice a loss of sensation, the appearance of your feet changing as a result of the deformity progressing, or severe pain in your feet, it is encouraged that you contact your doctor for early intervention.

Summary

Cavus foot is a condition characterised by a high arch in the foot. It can cause pain, instability, and walking difficulties. Early medical attention is important for proper diagnosis and treatment to prevent complications.