Understanding the Foot Arch

The human foot contains 26 bones, 33 joints and more than 100 muscles, tendons and ligaments that work together to support body weight and allow for walking, running and balance.

The medial longitudinal arch is higher than the lateral arch and plays a key role in shock absorption and propulsion, while the lateral arch is flatter and provides stability when standing. The transverse arch runs across the foot and helps maintain shape and flexibility. These arches are supported by ligaments, tendons and the plantar aponeurosis, which provides elasticity and strength, particularly to the medial arch.

Arch disorders occur when these structures fail to function properly, resulting in a collapsed arch (flatfoot) or an excessively high arch (cavus foot). Both conditions can alter alignment, increase stress on joints and soft tissues and contribute to chronic pain if left untreated. A normal arch is essential for proper weight distribution, shock absorption and overall foot stability.

What Is Flatfoot?

Flatfoot, also known as pes planus, occurs when the arch of the foot collapses and the sole of the foot comes into near-complete contact with the ground. Flat feet may be a normal developmental stage in infants and young children or may result from tissue damage, degeneration or structural abnormalities.

The presence or absence of a visible arch is an important clinical finding when assessing flatfoot, as it helps determine foot biomechanics and guides treatment decisions. A low arch often causes the foot to roll inward excessively during walking, leading to instability and uneven force distribution. Flatfoot may be present from childhood or develop later in adulthood.

Types of Flatfeet

• Flexible flatfoot: The arch appears when not bearing weight but flattens when standing
• Rigid flatfoot: The arch is absent both when standing and sitting
• Adult-acquired flatfoot: Develops over time, often due to tendon or ligament failure

Flatfoot is common in children, and most develop arches by about age 10. Some individuals, however, remain flat-footed into adulthood.

Adult-Acquired Flatfoot and Posterior Tibial Tendon Dysfunction

One of the most common causes of adult-acquired flatfoot is posterior tibial tendon dysfunction (PTTD). The posterior tibial tendon supports the medial arch and stabilizes the foot during walking. Its broad insertion helps maintain arch integrity and prevents excessive ligament strain.

As flatfoot progresses, the spring ligament may become stretched or torn and the deltoid ligament may lose its ability to prevent excessive ankle eversion. Injury or dysfunction involving multiple bones, tendons or ligaments can contribute to worsening deformity. When the posterior tibial tendon becomes inflamed, overstretched or torn, the arch gradually collapses.

Risk factors for PTTD and progressive collapsing foot deformity include age, female sex, obesity, diabetes and hypertension. This condition is more common in women and individuals over age 40.

Common Causes of PTTD and Adult Flatfoot

• Overuse or repetitive stress
• Previous ankle or foot injury
• Age-related tendon degeneration
• Obesity or prolonged standing
• Inflammatory conditions such as rheumatoid arthritis
• Congenital or developmental factors affecting arch formation

Symptoms

• Pain and swelling along the inside of the ankle or foot
• Progressive flattening of the arch
• Difficulty standing on tiptoes
• Outward rolling of the ankle
• Increasing pain with activity

Without treatment, adult-acquired flatfoot can progress to rigid deformity, joint arthritis and difficulty walking.

Other Arch Disorders

High Arch (Cavus Foot)

Cavus foot is characterized by an abnormally high arch that places excessive pressure on the heel and ball of the foot. This condition may lead to instability, pain, frequent ankle sprains and overuse injuries. Cavus foot can be associated with underlying neurologic conditions or muscle imbalance.

High arches may increase strain on the Achilles tendon and contribute to conditions such as Achilles tendonitis, shin splints and abnormal heel strike patterns. Stretching, physical therapy and supportive footwear play important roles in managing symptoms.

Accessory Navicular Syndrome

Some individuals have an extra bone or cartilage along the inner side of the foot near the arch. When irritated, this condition can cause pain, swelling and may contribute to flatfoot deformity.

Symptoms of Flatfoot and Arch Disorders

Symptoms vary based on severity and underlying cause but commonly include:

• Foot and ankle pain, especially along the arch or inside of the ankle
• Fatigue or aching after prolonged standing or walking
• Swelling along the inner ankle
• Changes in foot shape or alignment
• Difficulty with balance or uneven shoe wear
• Pain that extends to the knees, hips or lower back

Early evaluation is important to prevent progression and long-term complications.

How Flatfoot and Arch Disorders Are Diagnosed

Diagnosis begins with a comprehensive foot and ankle examination. OrthoTexas specialists evaluate:

• Foot alignment and arch height
• Gait mechanics and weight distribution
• Range of motion and joint stability
• Areas of tenderness or swelling

Visible arch height and foot arch type are important diagnostic indicators. Imaging studies such as X-rays, ultrasound or MRI may be used to assess bone alignment, tendon integrity and joint involvement. Weight-bearing imaging is often performed with the patient standing to accurately evaluate deformities under natural load conditions.

Non-Surgical Treatment Options

Many flatfoot and arch disorders can be managed successfully with non-surgical treatment, particularly when diagnosed early. Conservative care focuses on symptom relief, functional improvement and slowing progression.

Non-surgical options may include:

• Custom orthotics to support the arch and improve alignment
• Bracing or ankle supports for tendon protection and stability
• Physical therapy to strengthen supporting muscles and improve flexibility
• Activity modification to reduce stress on the foot
• Anti-inflammatory medications when appropriate
• Supportive footwear designed to reduce arch strain

Most patients in the early stages of progressive collapsing foot deformity respond well to non-surgical care.

When Surgery May Be Recommended

Surgery may be considered for patients with persistent pain, progressive deformity or loss of function that does not improve with conservative treatment. Surgical options depend on severity and may include:

• Tendon repair or reconstruction, including tendon transfer procedures
• Osteotomy to realign bones and restore arch structure
• Joint fusion in advanced or arthritic cases

The goal of surgery is to restore alignment, improve stability, relieve pain and enhance long-term foot function.

Complications and Risks

If left untreated, flatfoot and arch disorders can lead to chronic pain, progressive deformity, ankle instability, arthritis and difficulty with daily activities. High arches can also increase the risk of stress fractures and recurrent ankle injuries due to abnormal weight distribution.

Early diagnosis and appropriate treatment help minimize complications and protect long-term foot and ankle health.

Recovery and Rehabilitation

Recovery timelines vary depending on the condition and treatment approach. Non-surgical care may require weeks to months of therapy, while surgical recovery can take several months and may include:

• Temporary immobilization
• Gradual return to weight-bearing
• Physical therapy to restore strength and mobility
• Ongoing follow-up to monitor healing

Adhering to a structured rehabilitation plan is essential for optimal outcomes.

Expert Flatfoot and Arch Disorder Care at OrthoTexas

Flatfoot and arch disorders can significantly affect mobility and quality of life if left untreated. The foot and ankle specialists at OrthoTexas provide comprehensive diagnostic expertise and a full spectrum of non-surgical and surgical treatment options tailored to each patient’s needs.